Nanomaterials

13 pages, 4075 KiB

Open AccessArticle

Novel MOF-Based Photocatalyst AgBr/AgCl@ZIF-8 with Enhanced Photocatalytic Degradation and Antibacterial Properties

by Ning Liu, Jie Zhang, Yanhua Wang, Qingjun Zhu, Xuan Zhang, Jizhou Duan and Baorong Hou

Nanomaterials 2022, 12(11), 1946; https://doi.org/10.3390/nano12111946 - 06 Jun 2022

Cited by 11 | Viewed by 2559

A novel visible light-driven AgBr/AgCl@ZIF-8 catalyst was synthesized by a simple and rapid method. The composition and structure of the photocatalyst were characterized by XRD, SEM, UV-DRS, and XPS. It could be observed that the 2-methylimidazole zinc salt (ZIF-8) exhibited the rhombic dodecahedron [...] Read more.

A novel visible light-driven AgBr/AgCl@ZIF-8 catalyst was synthesized by a simple and rapid method. The composition and structure of the photocatalyst were characterized by XRD, SEM, UV-DRS, and XPS. It could be observed that the 2-methylimidazole zinc salt (ZIF-8) exhibited the rhombic dodecahedron morphology with the AgCl and AgBr particles evenly distributed around it. The composite photocatalyst AgBr/AgCl@ZIF-8 showed good photocatalytic degradation and antibacterial properties. The degradation rate of RhB solution was 98%, with 60 min of irradiation of visible light, and almost all P. aeruginosaudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli) were inactivated under the irradiation of 90 min. In addition, the prepared catalyst had excellent stability and reusability. Based on the free radical capture experiment, ·O₂⁻ and h⁺ were believed to be the main active substances, and possible photocatalytic degradation and sterilization mechanisms of AgBr/AgCl@ZIF-8 were proposed. Full article

(This article belongs to the Special Issue Hybrid Nanomaterials Applied to Photocatalysis)

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20 pages, 5743 KiB

Open AccessArticle

Ternary Nanohybrid of Ni₃S₂/CoMoS₄/MnO₂ on Nickel Foam for Aqueous and Solid-State High-Performance Supercapacitors

by Sumanta Sahoo, Ganesh Dhakal, Woo Kyoung Kim and Jae-Jin Shim

Nanomaterials 2022, 12(11), 1945; https://doi.org/10.3390/nano12111945 - 06 Jun 2022

Cited by 12 | Viewed by 1931

Abstract

To overcome the issues related to supercapacitor (SC) electrodes, such as high cost, low specific capacitance (C_s), low energy density (ED), requirements for expensive binder, etc., binderless electrodes are highly desirable. Here, a new ternary nanohybrid is presented as a [...] Read more.

To overcome the issues related to supercapacitor (SC) electrodes, such as high cost, low specific capacitance (C_s), low energy density (ED), requirements for expensive binder, etc., binderless electrodes are highly desirable. Here, a new ternary nanohybrid is presented as a binder-free SC electrode based on Ni₃S₂, CoMoS₄, and MnO₂. A facile two-step hydrothermal route, followed by a short thermal annealing process, is developed to grow amorphous polyhedral structured CoMoS₄ and further wrap MnO₂ nanowires on Ni foam. This rationally designed binder-free electrode exhibited the highest C_s of 2021 F g⁻¹ (specific capacity of 883.8 C g⁻¹ or 245.5 mAh g⁻¹) at a current density of 1 A g⁻¹ in 1 M KOH electrolyte with a highly porous surface morphology. This electrode material exhibited excellent cycling stability (90% capacitance retention after 4000 cycles) due to the synergistic contribution of individual components and advanced surface properties. Furthermore, an aqueous binder-free asymmetric SC based on this ternary composite exhibited an ED of 20.7 Wh kg⁻¹, whereas a solid-state asymmetric SC achieved an ED of 13.8 Wh kg⁻¹. This nanohybrid can be considered a promising binder-free electrode for both aqueous and solid-state asymmetric SCs with these remarkable electrochemical properties. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials for Energy Storage/Conversion and Catalysis in Korea)

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23 pages, 5510 KiB

Open AccessArticle

Green Synthesis via Eucalyptus globulus L. Extract of Ag-TiO₂ Catalyst: Antimicrobial Activity Evaluation toward Water Disinfection Process

by Jacqueline Torres-Limiñana, Ana A. Feregrino-Pérez, Marina Vega-González, Luis Escobar-Alarcón, José Antonio Cervantes-Chávez and Karen Esquivel

Nanomaterials 2022, 12(11), 1944; https://doi.org/10.3390/nano12111944 - 06 Jun 2022

Cited by 9 | Viewed by 2305

Abstract

The problem of water pollution by persistent substances and microorganisms requires solutions that materials such as silver-modified titanium dioxide can provide due to their excellent photocatalytic and antimicrobial properties. However, the synthesis methods conventionally used to obtain these materials involve toxic chemical reagents [...] Read more.

The problem of water pollution by persistent substances and microorganisms requires solutions that materials such as silver-modified titanium dioxide can provide due to their excellent photocatalytic and antimicrobial properties. However, the synthesis methods conventionally used to obtain these materials involve toxic chemical reagents such as sodium borohydride (NaBH₄). The search for alternative synthesis methods that use environmentally friendly substances, such as the biosynthesis method, was evaluated. Silver-titanium dioxide (Ag-TiO₂) was synthesized by a Eucalyptus globulus L. extract as a reductive agent through sol-gel and microwave-assisted sol-gel processes. Four different solvents were tested to extract secondary metabolites to determine their roles in reducing silver nanoparticles. Titanium dioxide nanoparticles with sizes from 11 to 14 nm were obtained in the anatase phase, and no narrowing of the bandgap was observed (3.1–3.2 eV) for the Ag-TiO₂ materials compared with the pure TiO₂. Interestingly, the bacterial inhibition values were close to 100%, suggesting an effective antimicrobial mechanism related to the properties of silver. Finally, by the physicochemical characterization of the materials and their antimicrobial properties, it was possible to obtain a suitable biosynthesized Ag-TiO₂ material as a green option for water disinfection that may be compared to the conventional methods. Full article

(This article belongs to the Special Issue Green Synthesis of Nanomaterials for Environmental and Biomedical Applications)

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19 pages, 8547 KiB

Open AccessArticle

Novel Graphene Oxide/Quercetin and Graphene Oxide/Juglone Nanostructured Platforms as Effective Drug Delivery Systems with Biomedical Applications

by Alexa-Maria Croitoru, Alina Moroșan, Bianca Tihăuan, Ovidiu Oprea, Ludmila Motelică, Roxana Trușcă, Adrian Ionuț Nicoară, Roxana-Cristina Popescu, Diana Savu, Dan Eduard Mihăiescu and Anton Ficai

Nanomaterials 2022, 12(11), 1943; https://doi.org/10.3390/nano12111943 - 06 Jun 2022

Cited by 19 | Viewed by 2228

Abstract

In this paper, novel drug delivery systems (DDS) were designed based on graphene oxide (GO) as nanocarrier, loaded with two natural substances (quercetin (Qu) and juglone (Ju)) at different concentrations. The chemical structure and morphology of the synthesized GO-based materials were characterized by [...] Read more.

In this paper, novel drug delivery systems (DDS) were designed based on graphene oxide (GO) as nanocarrier, loaded with two natural substances (quercetin (Qu) and juglone (Ju)) at different concentrations. The chemical structure and morphology of the synthesized GO-based materials were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Raman spectroscopy. The antibacterial activity was evaluated against standard strains, Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 8739, and Candida albicans ATCC 10231. Results demonstrated excellent antimicrobial activity, with a 5 log reduction of E. coli and a 1 log to 3.04 log reduction of S. aureus populations. Reduction rates were above 90%. Biocompatibility tests were also performed on GO-based materials, and the results showed biocompatible behavior for both L929 fibroblast cell line and BT474 breast cancer cells at lower concentrations. The identity of Qu and Ju was demonstrated by matrix-assisted laser desorption/ionization (MALDI) analysis, showing the compounds’ mass with high accuracy. In addition, specific properties of GO made it a versatile matrix for the MALDI analysis. The results of this study indicated that GO-based platforms may be suitable for applications in many areas for the effective and beneficial use of hydrophobic compounds such as Ju and Qu. Full article

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23 pages, 2360 KiB

Open AccessArticle

Targeted Immuno-Antiretroviral to Promote Dual Protection against HIV: A Proof-of-Concept Study

by Subhra Mandal, Shawnalyn W. Sunagawa, Pavan Kumar Prathipati, Michael Belshan, Annemarie Shibata and Christopher J. Destache

Nanomaterials 2022, 12(11), 1942; https://doi.org/10.3390/nano12111942 - 06 Jun 2022

Viewed by 1978

Abstract

The C–C motif chemokine receptor-5 (CCR5) expression on the T-cell surface is the prime barrier to HIV/AIDS eradication, as it promotes both active human immunodeficiency virus (HIV)-infection and latency; however, antiretrovirals (ARVs) suppress plasma viral loads to non-detectable levels. Keeping this in mind, [...] Read more.

The C–C motif chemokine receptor-5 (CCR5) expression on the T-cell surface is the prime barrier to HIV/AIDS eradication, as it promotes both active human immunodeficiency virus (HIV)-infection and latency; however, antiretrovirals (ARVs) suppress plasma viral loads to non-detectable levels. Keeping this in mind, we strategically designed a targeted ARVs-loaded nanoformulation that targets CCR5 expressing T-cells (e.g., CD4+ cells). Conceptually, CCR5-blocking and targeted ARV delivery would be a dual protection strategy to prevent HIV infection. For targeting CCR5+ T-cells, the nanoformulation was surface conjugated with anti-CCR5 monoclonal antibodies (CCR5 mAb) and loaded with dolutegravir+tenofovir alafenamide (D+T) ARVs to block HIV replication. The result demonstrated that the targeted-ARV nanoparticle’s multimeric CCR5 binding property improved its antigen-binding affinity, prolonged receptor binding, and ARV intracellular retention. Further, nanoformulation demonstrated high binding affinity to CCR5 expressing CD4+ cells, monocytes, and other CCR5+ T-cells. Finally, the short-term pre-exposure prophylaxis study demonstrated that prolonged CCR5 blockage and ARV presence further induced a “protective immune phenotype” with a boosted T-helper (Th), temporary memory (TM), and effector (E) sub-population. The proof-of-concept study that the targeted-ARV nanoformulation dual-action mechanism could provide a multifactorial solution toward achieving HIV “functional cure.” Full article

(This article belongs to the Special Issue Understanding the Bio–Nano Interactions in Nanomedicine: Functional Nanomaterials and Beyond)

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15 pages, 4751 KiB

Open AccessArticle

Enhanced Photocatalytic Activity and Photoluminescence of ZnO Nano-Wires Coupled with Aluminum Nanostructures

by Mondher Rtimi, Nour Beydoun, Artur Movsesyan, Suzanna Akil, Sergei Kostcheev, Xavier Gassmann, Mohamed Lajnef, Radhouane Chtourou and Safi Jradi

Nanomaterials 2022, 12(11), 1941; https://doi.org/10.3390/nano12111941 - 06 Jun 2022

Viewed by 1870

Abstract

In this study, we fabricated a hybrid plasmonic/semiconductor material by combining the chemical bath deposition of zinc oxide nanowires (ZnONWs) with the physical vapor deposition of aluminum nanostructures (AlNSs) under controlled temperature and atmosphere. The morphological and the optical properties of the ZnONWs/AlNSs [...] Read more.

In this study, we fabricated a hybrid plasmonic/semiconductor material by combining the chemical bath deposition of zinc oxide nanowires (ZnONWs) with the physical vapor deposition of aluminum nanostructures (AlNSs) under controlled temperature and atmosphere. The morphological and the optical properties of the ZnONWs/AlNSs hybrid material fabricated at different temperatures (250, 350, and 450 °C) and thicknesses (5, 7, and 9 nm) of Al layers were investigated. By adjusting the deposition and annealing parameters, it was possible to tune the size distribution of the AlNSs. The resonant coupling between the plasmonic AlNSs and ZnONWs leads to an enhanced photoluminescence response. The photocatalytic activity was studied through photodegradation under UV-light irradiation of methylene blue (MB) adsorbed at the surface of ZnO. The MB photodegradation experiment reveals that the ZnONWs covered with 7 nm aluminum film and annealed at 450 °C exhibit the highest degradation efficiency. The comparison between ZnONws and ZnONws/AlNSs shows a photoluminescence enhancement factor of 1.7 and an increase in the kinetics constant of photodegradation with a factor of 4. Full article

(This article belongs to the Special Issue Synthesis of Nanowires)

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13 pages, 4326 KiB

Open AccessArticle

Dendritic Mesoporous Silica Hollow Spheres for Nano-Bioreactor Application

by Qian Zhang, Minying Wu, Yuanyuan Fang, Chao Deng, Hsin-Hui Shen, Yi Tang and Yajun Wang

Nanomaterials 2022, 12(11), 1940; https://doi.org/10.3390/nano12111940 - 06 Jun 2022

Cited by 8 | Viewed by 2854

Abstract

Mesoporous silica materials have attracted great research interest for various applications ranging from (bio)catalysis and sensing to drug delivery. It remains challenging to prepare hollow mesoporous silica nanoparticles (HMSN) with large center-radial mesopores that could provide a more efficient transport channel through the [...] Read more.

Mesoporous silica materials have attracted great research interest for various applications ranging from (bio)catalysis and sensing to drug delivery. It remains challenging to prepare hollow mesoporous silica nanoparticles (HMSN) with large center-radial mesopores that could provide a more efficient transport channel through the cell for guest molecules. Here, we propose a novel strategy for the preparation of HMSN with large dendritic mesopores to achieve higher enzyme loading capacity and more efficient bioreactors. The materials were prepared by combining barium sulfate nanoparticles (BaSO₄ NP) as a hard template and the in situ-formed 3-aminophenol/formaldehyde resin as a porogen for directing the dendritic mesopores’ formation. HMSNs with different particle sizes, shell thicknesses, and pore structures have been prepared by choosing BaSO₄ NP of various sizes and adjusting the amount of tetraethyl orthosilicate added in synthesis. The obtained HMSN-1.1 possesses a high pore volume (1.07 cm³ g⁻¹), a large average pore size (10.9 nm), and dendritic mesopores that penetrated through the shell. The advantages of HMSNs are also demonstrated for enzyme (catalase) immobilization and subsequent use of catalase-loaded HMSNs as bioreactors for catalyzing the H₂O₂ degradation reaction. The hollow and dendritic mesoporous shell features of HMSNs provide abundant tunnels for molecular transport and more accessible surfaces for molecular adsorption, showing great promise in developing efficient nanoreactors and drug delivery vehicles. Full article

(This article belongs to the Special Issue Nanoporous Materials for Catalysis, Molecule Separation and Nanodevices)

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15 pages, 4233 KiB

Open AccessArticle

Erbium-Doped GQD-Embedded Coffee-Ground-Derived Porous Biochar for Highly Efficient Asymmetric Supercapacitor

by Thi Ai Ngoc Bui, Trung Viet Huynh, Hai Linh Tran and Ruey-an Doong

Nanomaterials 2022, 12(11), 1939; https://doi.org/10.3390/nano12111939 - 06 Jun 2022

Cited by 4 | Viewed by 2108

Abstract

A nanocomposite with erbium-doped graphene quantum dots embedded in highly porous coffee-ground-derived biochar (Er-GQD/HPB) was synthesized as a promising electrode material for a highly efficient supercapacitor. The HPB showed high porosity, with a large surface area of 1295 m² g⁻¹ and [...] Read more.

A nanocomposite with erbium-doped graphene quantum dots embedded in highly porous coffee-ground-derived biochar (Er-GQD/HPB) was synthesized as a promising electrode material for a highly efficient supercapacitor. The HPB showed high porosity, with a large surface area of 1295 m² g⁻¹ and an average pore size of 2.8 nm. The 2–8-nanometer Er-GQD nanoparticles were uniformly decorated on the HPB, subsequently increasing its specific surface area and thermal stability. Furthermore, the intimate contact between the Er-GQDs and HPB significantly reduced the charge-transfer resistance and diffusion path, leading to the rapid migration of ions/electrons in the mesoporous channels of the HPB. By adding Er-GQDs, the specific capacitance was dramatically increased from 337 F g⁻¹ for the pure HPB to 699 F g⁻¹ for the Er-GQD/HPB at 1 A g⁻¹. The Ragone plot of the Er-GQD/HPB exhibited an ultrahigh energy density of 94.5 Wh kg⁻¹ and a power density of 1.3 kW kg⁻¹ at 1 A g⁻¹. Furthermore, the Er-GQD/HPB electrode displayed excellent cycling stability, and 81% of the initial capacitance remained after 5000 cycles. Our results provide further insights into a promising supercapacitance material that offers the benefits of both fast ion transport from highly porous carbons and electrocatalytic improvement due to the embedment of Er-doped GQDs to enhance energy density relative to conventional materials. Full article

(This article belongs to the Special Issue Low-Dimensional Carbon-Based Nanomaterials for Photoelectrochemical Environmental and Energy Applications)

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11 pages, 2751 KiB

Open AccessEditor’s ChoiceArticle

Circular Optical Phased Arrays with Radial Nano-Antennas

by Qiankun Liu, Daniel Benedikovic, Tom Smy, Ahmad Atieh, Pavel Cheben and Winnie N. Ye

Nanomaterials 2022, 12(11), 1938; https://doi.org/10.3390/nano12111938 - 06 Jun 2022

Cited by 8 | Viewed by 2603

Abstract

On-chip optical phased arrays (OPAs) are the enabling technology for diverse applications, ranging from optical interconnects to metrology and light detection and ranging (LIDAR). To meet the required performance demands, OPAs need to achieve a narrow beam width and wide-angle steering, along with [...] Read more.

On-chip optical phased arrays (OPAs) are the enabling technology for diverse applications, ranging from optical interconnects to metrology and light detection and ranging (LIDAR). To meet the required performance demands, OPAs need to achieve a narrow beam width and wide-angle steering, along with efficient sidelobe suppression. A typical OPA configuration consists of either one-dimensional (1D) linear or two-dimensional (2D) rectangular arrays. However, the presence of grating sidelobes from these array configurations in the far-field pattern limits the aliasing-free beam steering, when the antenna element spacing is larger than half of a wavelength. In this work, we provide numerical analysis for 2D circular OPAs with radially arranged nano-antennas. The circular array geometry is shown to effectively suppress the grating lobes, expand the range for beam steering and obtain narrower beamwidths, while increasing element spacing to about 10 μm. To allow for high coupling efficiency, we propose the use of a central circular grating coupler to feed the designed circular OPA. Leveraging radially positioned nano-antennas and an efficient central grating coupler, our design can yield an aliasing-free azimuthal field of view (FOV) of 360°, while the elevation angle FOV is limited by the far-field beamwidth of the nano-antenna element and its array arrangement. With a main-to-sidelobe contrast ratio of 10 dB, a 110-element OPA offers an elevation FOV of 5° and an angular beamwidth of 1.14°, while an 870-element array provides an elevation FOV up to 20° with an angular beamwidth of 0.35°. Our analysis suggests that the performance of the circular OPAs can be further improved by integrating more elements, achieving larger aliasing-free FOV and narrower beamwidths. Our proposed design paves a new way for the development of on-chip OPAs with large 2D beam steering and high resolutions in communications and LIDAR systems. Full article

(This article belongs to the Special Issue Nanophotonics and Integrated Optics Devices)

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16 pages, 3214 KiB

Open AccessArticle

Promising Colloidal Rhenium Disulfide Nanosheets: Preparation and Applications for In Vivo Breast Cancer Therapy

by Yiwan Song, Yufeng Yuan, Xiao Peng, Zheng Peng, Hao Liu, Yingxin Zhou, Xiaoying Zhang, Feifan Zhou, Jun Song and Junle Qu

Nanomaterials 2022, 12(11), 1937; https://doi.org/10.3390/nano12111937 - 06 Jun 2022

Cited by 2 | Viewed by 2083

Abstract

Photothermal therapy (PTT) has become an important therapeutic strategy in the treatment of cancer. However, exploring novel photothermal nanomaterials with satisfactory biocompatibility, high photothermal conversion efficiency, and efficient theranostic outcomes, remains a major challenge for satisfying clinical application. In this study, poly-ethylene glycol [...] Read more.

Photothermal therapy (PTT) has become an important therapeutic strategy in the treatment of cancer. However, exploring novel photothermal nanomaterials with satisfactory biocompatibility, high photothermal conversion efficiency, and efficient theranostic outcomes, remains a major challenge for satisfying clinical application. In this study, poly-ethylene glycol modified rhenium disulfide (PEG-ReS₂) nanosheets are constructed by a simple-liquid phase exfoliation method. The PEG-ReS₂ nanosheets were demonstrated to have good solubility, good biocompatibility, low toxicity, and strong capability of accumulating near-infrared (NIR) photons. Under 808 nm laser irradiation, the PEG-ReS₂ nanosheets were found to have an excellent photothermal conversion efficiency (PTCE) of 42%. Moreover, the PEG-ReS₂ nanosheets were demonstrated to be ideal photothermal transduction agents (PTAs), which promoted rapid cancer cell death in vitro and efficiently ablated tumors in vivo. Interestingly, the potential utility of up-regulation or down-regulation of miRNAs was proposed to evaluate the therapeutic outcomes of PEG-ReS₂ nanosheets. The expression levels of a set of miRNAs in tumor-bearing mice were restored to normal levels after PTT therapy with PEG-ReS₂ nanosheets. Both down-regulation miRNAs (miR-125a-5p, miR-34a-5p, miR-132-3p, and miR-148b-3p) and up-regulation miRNAs (miR-133a-3p, miR-200c-5p, miR-9-3p, and miR-150-3p) were suggested to be important clinical biomarkers for evaluating therapeutic outcomes of breast cancer-related PTT. This work highlights the great significance of PEG-ReS₂ nanosheets as therapeutic nanoagents for cancer therapy. Full article

(This article belongs to the Special Issue Optical Nanotechnology for Biomedical Application)

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27 pages, 6017 KiB

Open AccessFeature PaperReview

Carbon-Coatings Improve Performance of Li-Ion Battery

by Ziling Chen, Qian Zhang and Qijie Liang

Nanomaterials 2022, 12(11), 1936; https://doi.org/10.3390/nano12111936 - 06 Jun 2022

Cited by 17 | Viewed by 5107

Abstract

The development of lithium-ion batteries largely relies on the cathode and anode materials. In particular, the optimization of cathode materials plays an extremely important role in improving the performance of lithium-ion batteries, such as specific capacity or cycling stability. Carbon coating modifying the [...] Read more.

The development of lithium-ion batteries largely relies on the cathode and anode materials. In particular, the optimization of cathode materials plays an extremely important role in improving the performance of lithium-ion batteries, such as specific capacity or cycling stability. Carbon coating modifying the surface of cathode materials is regarded as an effective strategy that meets the demand of Lithium-ion battery cathodes. This work mainly reviews the modification mechanism and method of carbon coating, and summarizes the recent progress of carbon coating on some typical cathode materials (LiFePO₄, LiMn₂O₄, LiCoO₂, NCA (LiNiCoAlO₂) and NCM (LiNiMnCoO₂)). In addition, the limitations of the carbon coating on the cathode are also introduced. Suggestions on improving the effectiveness of carbon coating for future study are also presented. Full article

(This article belongs to the Special Issue Advanced Nanomaterials and Nanotechnology for Green Energy Harvesting, Storage, and Application)

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1 pages, 164 KiB

Open AccessCorrection

Correction: Khan et al. High Mobility Graphene on EVA/PET. Nanomaterials 2022, 12, 331

by Munis Khan, Kornelia Indykiewicz, Pui Lam Tam and August Yurgens

Nanomaterials 2022, 12(11), 1935; https://doi.org/10.3390/nano12111935 - 06 Jun 2022

Viewed by 1086

Abstract

The authors wish to make following corrections in this paper [...] Full article

8 pages, 2540 KiB

Open AccessArticle

Field Electron Emission from Crumpled CVD Graphene Patterns Printed via Laser-Induced Forward Transfer

by Maxim Komlenok, Nikolay Kurochitsky, Pavel Pivovarov, Maxim Rybin and Elena Obraztsova

Nanomaterials 2022, 12(11), 1934; https://doi.org/10.3390/nano12111934 - 06 Jun 2022

Cited by 6 | Viewed by 1808

Abstract

A new approach to the fabrication of graphene field emitters on a variety of substrates at room temperature and in an ambient environment is demonstrated. The required shape and orientation of the graphene flakes along the field are created by the blister-based laser-induced [...] Read more.

A new approach to the fabrication of graphene field emitters on a variety of substrates at room temperature and in an ambient environment is demonstrated. The required shape and orientation of the graphene flakes along the field are created by the blister-based laser-induced forward transfer of CVD high-quality single-layer graphene. The proposed technique allows the formation of emitting crumpled graphene patterns without losing the quality of the initially synthesized graphene, as shown by Raman spectroscopy. The electron field emission properties of crumpled graphene imprints 1 × 1 mm² in size were studied. The transferred graphene flakes demonstrated good adhesion and emission characteristics. Full article

(This article belongs to the Special Issue Laser Synthesis and Processing of Nanostructured Materials)

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27 pages, 6639 KiB

Open AccessReview

Silver Nanowires in Stretchable Resistive Strain Sensors

by Srinivasan Raman and Ravi Sankar Arunagirinathan

Nanomaterials 2022, 12(11), 1932; https://doi.org/10.3390/nano12111932 - 06 Jun 2022

Cited by 10 | Viewed by 4364

Abstract

Silver nanowires (AgNWs), having excellent electrical conductivity, transparency, and flexibility in polymer composites, are reliable options for developing various sensors. As transparent conductive electrodes (TCEs), AgNWs are applied in optoelectronics, organic electronics, energy devices, and flexible electronics. In recent times, research groups across [...] Read more.

Silver nanowires (AgNWs), having excellent electrical conductivity, transparency, and flexibility in polymer composites, are reliable options for developing various sensors. As transparent conductive electrodes (TCEs), AgNWs are applied in optoelectronics, organic electronics, energy devices, and flexible electronics. In recent times, research groups across the globe have been concentrating on developing flexible and stretchable strain sensors with a specific focus on material combinations, fabrication methods, and performance characteristics. Such sensors are gaining attention in human motion monitoring, wearable electronics, advanced healthcare, human-machine interfaces, soft robotics, etc. AgNWs, as a conducting network, enhance the sensing characteristics of stretchable strain-sensing polymer composites. This review article presents the recent developments in resistive stretchable strain sensors with AgNWs as a single or additional filler material in substrates such as polydimethylsiloxane (PDMS), thermoplastic polyurethane (TPU), polyurethane (PU), and other substrates. The focus is on the material combinations, fabrication methods, working principles, specific applications, and performance metrics such as sensitivity, stretchability, durability, transparency, hysteresis, linearity, and additional features, including self-healing multifunctional capabilities. Full article

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13 pages, 3914 KiB

Open AccessArticle

Green Synthesis of Lead Sulphide Nanoparticles for High-Efficiency Perovskite Solar Cell Applications

by Mohammad Aminul Islam, Dilip Kumar Sarkar, Md. Shahinuzzaman, Yasmin Abdul Wahab, Mayeen Uddin Khandaker, Nissren Tamam, Abdelmoneim Sulieman, Nowshad Amin and Md. Akhtaruzzaman

Nanomaterials 2022, 12(11), 1933; https://doi.org/10.3390/nano12111933 - 05 Jun 2022

Cited by 14 | Viewed by 2556

Abstract

In this study, lead sulfide (PbS) nanoparticles were synthesized by the chemical precipitation method using Aloe Vera extract with PbCl₂ and Thiourea (H₂N-CS-NH₂). The synthesized nanoparticles have been investigated using x-ray diffraction (XRD), UV-Vis, energy-dispersive x-ray spectroscopy (EDX), [...] Read more.

In this study, lead sulfide (PbS) nanoparticles were synthesized by the chemical precipitation method using Aloe Vera extract with PbCl₂ and Thiourea (H₂N-CS-NH₂). The synthesized nanoparticles have been investigated using x-ray diffraction (XRD), UV-Vis, energy-dispersive x-ray spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD and TEM results confirm that the films are in the cubic phase. The crystallite size, lattice constant, micro-strain, dislocation density, optical bandgap, etc. have been determined using XRD and UV-Vis for investigating the quality of prepared nanoparticles. The possible application of these synthesized nanoparticles in the solar cells was investigated by fabricating the thin films on an FTO-coated and bare glass substrate. The properties of nanoparticles were found to be nearly retained in the film state as well. The experimentally found properties of thin films have been implemented for perovskite solar cell simulation and current-voltage and capacitance-voltage characteristics have been investigated. The simulation results showed that PbS nanoparticles could be a potential hole transport layer for high-efficiency perovskite solar cell applications. Full article

(This article belongs to the Special Issue Stable Perovskite Materials: From Synthesis to Optoelectronic Devices)

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11 pages, 2726 KiB

Open AccessArticle

Tunable Carrier Transfer of Polymeric Carbon Nitride with Charge-Conducting CoV₂O₆∙2H₂O for Photocatalytic O₂ Evolution

by Shaohong Zang, Xiaorong Cai, Mengshan Chen, Dehong Teng, Fei Jing, Zhe Leng, Yingtang Zhou and Feng Lin

Nanomaterials 2022, 12(11), 1931; https://doi.org/10.3390/nano12111931 - 05 Jun 2022

Cited by 5 | Viewed by 1842

Abstract

Photocatalytic water splitting is one of the promising approaches to solving environmental problems and energy crises. However, the sluggish 4e⁻ transfer kinetics in water oxidation half-reaction restricts the 2e⁻ reduction efficiency in photocatalytic water splitting. Herein, cobalt vanadate-decorated polymeric carbon nitride [...] Read more.

Photocatalytic water splitting is one of the promising approaches to solving environmental problems and energy crises. However, the sluggish 4e⁻ transfer kinetics in water oxidation half-reaction restricts the 2e⁻ reduction efficiency in photocatalytic water splitting. Herein, cobalt vanadate-decorated polymeric carbon nitride (named CoVO/PCN) was constructed to mediate the carrier kinetic process in a photocatalytic water oxidation reaction (WOR). The photocatalysts were well-characterized by various physicochemical techniques such as XRD, FT-IR, TEM, and XPS. Under UV and visible light irradiation, the O₂ evolution rate of optimized 3 wt% CoVO/PCN reached 467 and 200 μmol h⁻¹ g⁻¹, which were about 6.5 and 5.9 times higher than that of PCN, respectively. Electrochemical tests and PL results reveal that the recombination of photogenerated carriers on PCN is effectively suppressed and the kinetics of WOR is significantly enhanced after CoVO introduction. This work highlights key features of the tuning carrier kinetics of PCN using charge-conducting materials, which should be the basis for the further development of photocatalytic O₂ reactions. Full article

(This article belongs to the Special Issue Application of Nanomaterials in Photodegradation)

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31 pages, 13873 KiB

Open AccessEditor’s ChoiceArticle

One A₃B Porphyrin Structure—Three Successful Applications

by Ion Fratilescu, Anca Lascu, Bogdan Ovidiu Taranu, Camelia Epuran, Mihaela Birdeanu, Ana-Maria Macsim, Eugenia Tanasa, Eugeniu Vasile and Eugenia Fagadar-Cosma

Nanomaterials 2022, 12(11), 1930; https://doi.org/10.3390/nano12111930 - 05 Jun 2022

Cited by 7 | Viewed by 2662

Abstract

Porphyrins are versatile structures capable of acting in multiple ways. A mixed substituted A₃B porphyrin, 5-(3-hydroxy-phenyl)-10,15,20-tris-(3-methoxy-phenyl)-porphyrin and its Pt(II) complex, were synthesised and fully characterised by ¹H- and ¹³C-NMR, TLC, UV-Vis, FT-IR, fluorescence, AFM, TEM and SEM with EDX [...] Read more.

Porphyrins are versatile structures capable of acting in multiple ways. A mixed substituted A₃B porphyrin, 5-(3-hydroxy-phenyl)-10,15,20-tris-(3-methoxy-phenyl)-porphyrin and its Pt(II) complex, were synthesised and fully characterised by ¹H- and ¹³C-NMR, TLC, UV-Vis, FT-IR, fluorescence, AFM, TEM and SEM with EDX microscopy, both in organic solvents and in acidic mediums. The pure compounds were used, firstly, as sensitive materials for sensitive and selective optical and fluorescence detection of hydroquinone with the best results in the range 0.039–6.71 µM and a detection limit of 0.013 µM and, secondly, as corrosion inhibitors for carbon–steel (OL) in an acid medium giving a best performance of 88% in the case of coverings with Pt-porphyrin. Finally, the electrocatalytic activity for the hydrogen and oxygen evolution reactions (HER and OER) of the free-base and Pt-metalated A₃B porphyrins was evaluated in strong alkaline and acidic electrolyte solutions. The best results were obtained for the electrode modified with the metalated porphyrin, drop-casted on a graphite substrate from an N,N-dimethylformamide solution. In the strong acidic medium, the electrode displayed an HER overpotential of 108 mV, at i = −10 mA/cm² and a Tafel slope value of 205 mV/dec. Full article

(This article belongs to the Special Issue Multifunctional Nanomaterials and Hybrid Structures for Sensors, Actuators and Smart Technologies)

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20 pages, 4115 KiB

Open AccessReview

Strain-Modulated Magnetism in MoS₂

by Hongtao Ren and Gang Xiang

Nanomaterials 2022, 12(11), 1929; https://doi.org/10.3390/nano12111929 - 04 Jun 2022

Cited by 10 | Viewed by 3283

Abstract

Since the experiments found that two-dimensional (2D) materials such as single-layer MoS₂ can withstand up to 20% strain, strain-modulated magnetism has gradually become an emerging research field. However, applying strain alone is difficult to modulate the magnetism of single-layer pristine MoS₂ [...] Read more.

Since the experiments found that two-dimensional (2D) materials such as single-layer MoS₂ can withstand up to 20% strain, strain-modulated magnetism has gradually become an emerging research field. However, applying strain alone is difficult to modulate the magnetism of single-layer pristine MoS₂, but applying strain combined with other tuning techniques such as introducing defects makes it easier to produce and alter the magnetism in MoS₂. Here, we summarize the recent progress of strain-dependent magnetism in MoS₂. First, we review the progress in theoretical study. Then, we compare the experimental methods of applying strain and their effects on magnetism. Specifically, we emphasize the roles played by web buckles, which induce biaxial tensile strain conveniently. Despite some progress, the study of strain-dependent MoS₂ magnetism is still in its infancy, and a few potential directions for future research are discussed at the end. Overall, a broad and in-depth understanding of strain-tunable magnetism is very necessary, which will further drive the development of spintronics, straintronics, and flexible electronics. Full article

(This article belongs to the Special Issue Review Papers in 2D and Carbon Nanomaterials)

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18 pages, 5443 KiB

Open AccessArticle

Investigation of Heater Structures for Thermal Conductivity Measurements of SiO₂ and Al₂O₃ Thin Films Using the 3-Omega Method

by Fabian Kühnel, Christoph Metzke, Jonas Weber, Josef Schätz, Georg S. Duesberg and Günther Benstetter

Nanomaterials 2022, 12(11), 1928; https://doi.org/10.3390/nano12111928 - 04 Jun 2022

Cited by 1 | Viewed by 2162

Abstract

A well-known method for measuring thermal conductivity is the 3-Omega (3ω) method. A prerequisite for it is the deposition of a metal heater on top of the sample surface. The known design rules for the heater geometry, however, are not yet [...] Read more.

A well-known method for measuring thermal conductivity is the 3-Omega (3ω) method. A prerequisite for it is the deposition of a metal heater on top of the sample surface. The known design rules for the heater geometry, however, are not yet sufficient. In this work, heaters with different lengths and widths within the known restrictions were investigated. The measurements were carried out on SiO₂ thin films with different film thicknesses as a reference. There was a significant difference between theoretical deposited heater width and real heater width, which could lead to errors of up to 50% for the determined thermal conductivity. Heaters with lengths between 11 and 13 mm and widths of 6.5 µm or more proved to deliver the most trustworthy results. To verify the performance of these newfound heaters, additional investigations on Al₂O₃ thin films were carried out, proving our conclusions to be correct and delivering thermal conductivity values of 0.81 Wm⁻¹ K⁻¹ and 0.93 Wm⁻¹ K⁻¹ for unannealed and annealed samples, respectively. Furthermore, the effect of annealing on Al₂O₃ was studied, revealing a significant shrinking in film thickness of approximately 11% and an increase in thermal conductivity of 15%. The presented results on well-defined geometries will help to produce optimized heater structures for the 3ω method. Full article

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20 pages, 12833 KiB

Open AccessArticle

Utilization of Carbon-Based Nanomaterials and Plate-Fin Networks in a Cold PCM Container with Application in Air Conditioning of Buildings

by Farhad Afsharpanah, Goshtasp Cheraghian, Farzam Akbarzadeh Hamedani, Elham Shokri and Seyed Soheil Mousavi Ajarostaghi

Nanomaterials 2022, 12(11), 1927; https://doi.org/10.3390/nano12111927 - 04 Jun 2022

Cited by 26 | Viewed by 2072

Abstract

Cold energy storage devices are widely used for coping with the mismatch between thermal energy production and demand. These devices can store cold thermal energy and return it when required. Besides the countless advantages of these devices, their freezing rate is sluggish, therefore [...] Read more.

Cold energy storage devices are widely used for coping with the mismatch between thermal energy production and demand. These devices can store cold thermal energy and return it when required. Besides the countless advantages of these devices, their freezing rate is sluggish, therefore researchers are continuously searching for techniques to improve their operating speed. This paper tries to address this problem by simultaneously combining a network of plate fins and various types of carbon-based nanomaterials (NMs) in a series of complex computational fluid dynamics (CFD) simulations that are validated by published experimental results. Horizontal, vertical, and the combination of these two plate-fin arrangements are tested and compared to the base model. Subsequently, several carbon-based NMs, including SWCNT, MWCNT, and graphene-oxide NMs are utilized to further improve the process. The influence of these fin networks, nanoparticle types, and their volume- and mass-based concentrations within the PCM container are studied and discussed. According to the results, carbon-based NMs exhibit superior performance compared to metal-oxide NMs, so that at identical NM volume and mass fractions, MWCNT particles present a 2.77% and 17.72% faster freezing rate than the CuO particles. The combination of plate-fin network and MWCNT particles is a promising technique that can expedite the ice formation rate by up to 70.14%. Full article

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13 pages, 2990 KiB

Open AccessArticle

Ratiometric Upconversion Temperature Sensor Based on Cellulose Fibers Modified with Yttrium Fluoride Nanoparticles

by Małgorzata Skwierczyńska, Natalia Stopikowska, Piotr Kulpiński, Magdalena Kłonowska, Stefan Lis and Marcin Runowski

Nanomaterials 2022, 12(11), 1926; https://doi.org/10.3390/nano12111926 - 04 Jun 2022

Cited by 4 | Viewed by 2063

Abstract

In this study, an optical thermometer based on regenerated cellulose fibers modified with YF₃: 20% Yb³⁺, 2% Er³⁺ nanoparticles was developed. The presented sensor was fabricated by introducing YF₃ nanoparticles into cellulose fibers during their formation by [...] Read more.

In this study, an optical thermometer based on regenerated cellulose fibers modified with YF₃: 20% Yb³⁺, 2% Er³⁺ nanoparticles was developed. The presented sensor was fabricated by introducing YF₃ nanoparticles into cellulose fibers during their formation by the so-called Lyocell process using N-methylmorpholine N-oxide as a direct solvent of cellulose. Under near-infrared excitation, the applied nanoparticles exhibited thermosensitive upconversion emission, which originated from the thermally coupled levels of Er³⁺ ions. The combination of cellulose fibers with upconversion nanoparticles resulted in a flexible thermometer that is resistant to environmental and electromagnetic interferences and allows precise and repeatable temperature measurements in the range of 298–362 K. The obtained fibers were used to produce a fabric that was successfully applied to determine human skin temperature, demonstrating its application potential in the field of wearable health monitoring devices and providing a promising alternative to thermometers based on conductive materials that are sensitive to electromagnetic fields. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

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14 pages, 6363 KiB

Open AccessArticle

Nanohollow Titanium Oxide Structures on Ti/FTO Glass Formed by Step-Bias Anodic Oxidation for Photoelectrochemical Enhancement

by Chi-Hsien Huang, Yu-Jen Lu, Yong-Chen Pan, Hui-Ling Liu, Jia-Yuan Chang, Jhao-Liang Sie, Dorota G. Pijanowska and Chia-Ming Yang

Nanomaterials 2022, 12(11), 1925; https://doi.org/10.3390/nano12111925 - 04 Jun 2022

Cited by 2 | Viewed by 1622

Abstract

In this study, a new anodic oxidation with a step-bias increment is proposed to evaluate oxidized titanium (Ti) nanostructures on transparent fluorine-doped tin oxide (FTO) on glass. The optimal Ti thickness was determined to be 130 nm. Compared to the use of a [...] Read more.

In this study, a new anodic oxidation with a step-bias increment is proposed to evaluate oxidized titanium (Ti) nanostructures on transparent fluorine-doped tin oxide (FTO) on glass. The optimal Ti thickness was determined to be 130 nm. Compared to the use of a conventional constant bias of 25 V, a bias ranging from 5 V to 20 V with a step size of 5 V for 3 min per period can be used to prepare a titanium oxide (TiO_x) layer with nanohollows that shows a large increase in current of 142% under UV illumination provided by a 365 nm LED at a power of 83 mW. Based on AFM and SEM, the TiO_x grains formed in the step-bias anodic oxidation were found to lead to nanohollow generation. Results obtained from EDS mapping, HR-TEM and XPS all verified the TiO_x composition and supported nanohollow formation. The nanohollows formed in a thin TiO_x layer can lead to a high surface roughness and photon absorbance for photocurrent generation. With this step-bias anodic oxidation methodology, TiO_x with nanohollows can be obtained easily without any extra cost for realizing a high current under photoelectrochemical measurements that shows potential for electrochemical-based sensing applications. Full article

(This article belongs to the Special Issue Nanotechnologies and Nanomaterials: Selected Papers from CCMR)

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9 pages, 686 KiB

Open AccessArticle

Control over the Surface Properties of Zinc Oxide Powders via Combining Mechanical, Electron Beam, and Thermal Processing

by Igor A. Pronin, Igor A. Averin, Andrey A. Karmanov, Nadezhda D. Yakushova, Alexey S. Komolov, Eleonora F. Lazneva, Maxim M. Sychev, Vyacheslav A. Moshnikov and Ghenadii Korotcenkov

Nanomaterials 2022, 12(11), 1924; https://doi.org/10.3390/nano12111924 - 04 Jun 2022

Cited by 3 | Viewed by 1827

Abstract

The surface properties of zinc oxide powders prepared using mechanical activation, electron beam irradiation, and vacuum annealing, as well using combinations of these types of treatments, were studied using X-ray photoelectron spectroscopy. The structure of the obtained materials was studied by an X-ray [...] Read more.

The surface properties of zinc oxide powders prepared using mechanical activation, electron beam irradiation, and vacuum annealing, as well using combinations of these types of treatments, were studied using X-ray photoelectron spectroscopy. The structure of the obtained materials was studied by an X-ray diffraction technique and by scanning electron microscopy. We found that over five hours of grinding in an attritor, the size of nanocrystals decreases from 37 to 21 nm, and microdeformations increase from 0.3% to 0.6%. It was also found that a five-hour grinding treatment promoted formation of vacancies in the zinc sublattice at the surface and diffusion of Zn²⁺ cations into the bulk of the material. Irradiation of commercial zinc oxide powders with an electron beam with an energy of 0.9 MeV and a dose of 1 MGy induced breaking of Zn–O bonds, diffusion of interstitial zinc ions into the bulk, and oxygen atom escape from regular positions into the gas phase. A combined treatment of five hours of grinding and electron beam irradiation promoted accumulation of interstitial zinc ions at the surface of the material. Annealing of both initial and mechanically activated ZnO powders at temperatures up to 400 °C did not lead to a significant change in the properties of the samples. Upon exceeding the 400 °C annealing temperature the X-ray photoelectron spectra show almost identical atomic composition of the two types of materials, which is related to diffusion of interstitial zinc ions from the bulk of the material to the surface. Full article

(This article belongs to the Special Issue Advances in Microscopy and Spectroscopy Techniques Applied to Nanomaterials)

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4 pages, 194 KiB

Open AccessEditorial

Special Issue “Nanomaterials for Biomedical and Biotechnological Applications”

by Angelo Ferraro

Nanomaterials 2022, 12(11), 1923; https://doi.org/10.3390/nano12111923 - 04 Jun 2022

Viewed by 1089

Abstract

In the last few decades, biomedical and biotechnological researchers have turned their interest to nanocomposite materials [...] Full article

(This article belongs to the Special Issue Nanomaterials for Biomedical and Biotechnological Applications)

24 pages, 3088 KiB

Open AccessEditor’s ChoiceReview

Reactive Oxygen Species Formed by Metal and Metal Oxide Nanoparticles in Physiological Media—A Review of Reactions of Importance to Nanotoxicity and Proposal for Categorization

by Amanda Kessler, Jonas Hedberg, Eva Blomberg and Inger Odnevall

Nanomaterials 2022, 12(11), 1922; https://doi.org/10.3390/nano12111922 - 04 Jun 2022

Cited by 55 | Viewed by 4099

Abstract

Diffusely dispersed metal and metal oxide nanoparticles (NPs) can adversely affect living organisms through various mechanisms and exposure routes. One mechanism behind their toxic potency is their ability to generate reactive oxygen species (ROS) directly or indirectly to an extent that depends on [...] Read more.

Diffusely dispersed metal and metal oxide nanoparticles (NPs) can adversely affect living organisms through various mechanisms and exposure routes. One mechanism behind their toxic potency is their ability to generate reactive oxygen species (ROS) directly or indirectly to an extent that depends on the dose, metal speciation, and exposure route. This review provides an overview of the mechanisms of ROS formation associated with metal and metal oxide NPs and proposes a possible way forward for their future categorization. Metal and metal oxide NPs can form ROS via processes related to corrosion, photochemistry, and surface defects, as well as via Fenton, Fenton-like, and Haber–Weiss reactions. Regular ligands such as biomolecules can interact with metallic NP surfaces and influence their properties and thus their capabilities of generating ROS by changing characteristics such as surface charge, surface composition, dissolution behavior, and colloidal stability. Interactions between metallic NPs and cells and their organelles can indirectly induce ROS formation via different biological responses. H₂O₂ can also be generated by a cell due to inflammation, induced by interactions with metallic NPs or released metal species that can initiate Fenton(-like) and Haber–Weiss reactions forming various radicals. This review discusses these different pathways and, in addition, nano-specific aspects such as shifts in the band gaps of metal oxides and how these shifts at biologically relevant energies (similar to activation energies of biological reactions) can be linked to ROS production and indicate which radical species forms. The influences of kinetic aspects, interactions with biomolecules, solution chemistry (e.g., Cl⁻ and pH), and NP characteristics (e.g., size and surface defects) on ROS mechanisms and formation are discussed. Categorization via four tiers is suggested as a way forward to group metal and metal oxide NPs based on the ROS reaction pathways that they may undergo, an approach that does not include kinetics or environmental variations. The criteria for the four tiers are based on the ability of the metallic NPs to induce Fenton(-like) and Haber–Weiss reactions, corrode, and interact with biomolecules and their surface catalytic properties. The importance of considering kinetic data to improve the proposed categorization is highlighted. Full article

(This article belongs to the Special Issue Advances in Nano-Bio Interactions: Nanosafety and Nanotoxicology)

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20 pages, 4860 KiB

Open AccessArticle

Synthesis of Iron, Zinc, and Manganese Nanofertilizers, Using Andean Blueberry Extract, and Their Effect in the Growth of Cabbage and Lupin Plants

by Erika Murgueitio-Herrera, César E. Falconí, Luis Cumbal, Josselyn Gómez, Karina Yanchatipán, Alejandro Tapia, Kevin Martínez, Izar Sinde-Gonzalez and Theofilos Toulkeridis

Nanomaterials 2022, 12(11), 1921; https://doi.org/10.3390/nano12111921 - 04 Jun 2022

Cited by 15 | Viewed by 3064

Abstract

The predominant aim of the current study was to synthesize the nanofertilizer nanoparticles ZnO_MnO-NPs and FeO_ZnO-NPs using Andean blueberry extract and determine the effect of NPs in the growth promotion of cabbage (Brassica oleracea var. capitata) and Andean lupin (Lupinus [...] Read more.

The predominant aim of the current study was to synthesize the nanofertilizer nanoparticles ZnO_MnO-NPs and FeO_ZnO-NPs using Andean blueberry extract and determine the effect of NPs in the growth promotion of cabbage (Brassica oleracea var. capitata) and Andean lupin (Lupinus mutabilis sweet) crops. The nanoparticles were analyzed by visible spectrophotometry, size distribution (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Solutions of nanoparticle concentrations were applied to cabbage, with solutions of 270 and 540 ppm of ZnO_MnO-NPs and 270 and 540 ppm of FeO_ZnO-NPs applied to Andean lupin. Zinc was used in both plants to take advantage of its beneficial properties for plant growth. Foliar NPs sprays were applied at the phenological stage of vegetative growth of the cabbage or Andean lupin plants grown under greenhouse conditions. The diameter of the NPs was 9.5 nm for ZnO, 7.8 nm for FeO, and 10.5 nm for MnO, which facilitate the adsorption of NPs by the stomata of plants. In Andean lupin, treatment with 270 ppm of iron and zinc indicated increases of 6% in height, 19% in root size, 3.5% in chlorophyll content index, and 300% in leaf area, while treatment with 540 ppm of iron and zinc yielded no apparent increases in any variable. In cabbage, the ZnO_MnO-NPs indicate, at a concentration of 270 ppm, increases of 10.3% in root size, 55.1% in dry biomass, 7.1% in chlorophyll content, and 25.6% in leaf area. Cabbage plants treated at a concentration of 540 ppm produced increases of 1.3% in root size and 1.8% in chlorophyll content, compared to the control, which was sprayed with distilled water. Therefore, the spray application of nanofertilizers at 270 ppm indicated an important improvement in both plants’ growth. Full article

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17 pages, 4694 KiB

Open AccessArticle

Electrolytes with Micelle-Assisted Formation of Directional Ion Transport Channels for Aqueous Rechargeable Batteries with Impressive Performance

by Yanmin Lu, Fengxiang Zhang, Xifeng Lu, Haihui Jiang, Wei Hu, Libin Liu and Ligang Gai

Nanomaterials 2022, 12(11), 1920; https://doi.org/10.3390/nano12111920 - 04 Jun 2022

Cited by 3 | Viewed by 2169

Abstract

Low-cost and ecofriendly electrolytes with suppressed water reactivity and raised ionic conductivity are desirable for aqueous rechargeable batteries because it is a dilemma to decrease the water reactivity and increase the ionic conductivity at the same time. In this paper, Li₂SO [...] Read more.

Low-cost and ecofriendly electrolytes with suppressed water reactivity and raised ionic conductivity are desirable for aqueous rechargeable batteries because it is a dilemma to decrease the water reactivity and increase the ionic conductivity at the same time. In this paper, Li₂SO₄–Na₂SO₄–sodium dodecyl sulfate (LN-SDS)-based aqueous electrolytes are designed, where: (i) Na⁺ ions dissociated from SDS increase the charge carrier concentration, (ii) DS⁻/SO₄²⁻ anions and Li⁺/Na⁺ cations are capable of trapping water molecules through hydrogen bonding and/or hydration, resulting in a lowered melting point, (iii) Li⁺ ions reduce the Krafft temperature of LN-SDS, (iv) Na⁺ and SO₄²⁻ ions increase the low-temperature electrolyte ionic conductivity, and (v) SDS micelle clusters are orderly aggregated to form directional ion transport channels, enabling the formation of quasi-continuous ion flows without (r.t.) and with (≤0 °C) applying voltage. The screened LN-SDS is featured with suppressed water reactivity and high ionic conductivity at temperatures ranging from room temperature to −15 °C. Additionally, NaTi₂(PO₄)₃‖LiMn₂O₄ batteries operating with LN-SDS manifest impressive electrochemical performance at both room temperature and −15 °C, especially the cycling stability and low-temperature performance. Full article

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13 pages, 3032 KiB

Open AccessArticle

Sonochemical-Assisted Biogenic Synthesis of Theophrasite β-Ni(OH)₂ Nanocluster Using Chia Seeds Extract: Characterization and Anticancer Activity

by Hanaa A. Hassanin and Amel Taha

Nanomaterials 2022, 12(11), 1919; https://doi.org/10.3390/nano12111919 - 03 Jun 2022

Cited by 4 | Viewed by 2093

Abstract

Theophrasite β-Ni(OH)₂ nanocluster were fabricated via the sonochemical-assisted biogenic method using chia seeds extract as a reducing and stabilizing agent. The optical and morphological feature of the synthesized nanocluster was characterized using UV-Vis, FTIR, FE-SEM-EDS, HR-TEM, DLS, XPS, and XRD analysis. According [...] Read more.

Theophrasite β-Ni(OH)₂ nanocluster were fabricated via the sonochemical-assisted biogenic method using chia seeds extract as a reducing and stabilizing agent. The optical and morphological feature of the synthesized nanocluster was characterized using UV-Vis, FTIR, FE-SEM-EDS, HR-TEM, DLS, XPS, and XRD analysis. According to FE-SEM and HR-TEM images of the synthesized materials, β-Ni(OH)₂ nanocluster illustrates the hexagonal particle shape with an average size of 5.8 nm, while the EDS results confirm the high purity of the synthesized nanocluster. Moreover, the XRD pattern of the synthesized materials shows typical peaks that match the reference pattern of the Theophrasite form of β-Ni(OH)₂ with a hexagonal crystal system. The XPS analysis illustrates that the prepared samples exhibit both Ni²⁺ and Ni³⁺ with the predominance of Ni²⁺ species. Additionally the in-vitro cytotoxic activity of β-Ni(OH)₂ nanocluster is tested against the MCF7 cell lines (breast cancer cells). The MTT assay results proved that the synthesized β-Ni(OH)₂ nanocluster has potent cytotoxic activity against breast cancer cell lines (IC₅₀: 62.7 μg/mL). Full article

(This article belongs to the Topic Synthesis and Applications of Nanostructured Metals and Metal Oxides)

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14 pages, 3879 KiB

Open AccessCommunication

Enhanced Photocatalytic Hydrogen Production Activity by Constructing a Robust Organic-Inorganic Hybrid Material Based Fulvalene and TiO₂

by Mengyuan Wang, Shizhuo Su, Xin Zhong, Derui Kong, Bo Li, Yujie Song, Chunman Jia and Yifan Chen

Nanomaterials 2022, 12(11), 1918; https://doi.org/10.3390/nano12111918 - 03 Jun 2022

Cited by 5 | Viewed by 1828

Abstract

A novel redox-active organic-inorganic hybrid material (denoted as H₄TTFTB-TiO₂) based on tetrathiafulvalene derivatives and titanium dioxide with a micro/mesoporous nanomaterial structure has been synthesized via a facile sol-gel method. In this study, tetrathiafulvalene-3,4,5,6-tetrakis(4-benzoic acid) (H₄TTFTB) is an [...] Read more.

A novel redox-active organic-inorganic hybrid material (denoted as H₄TTFTB-TiO₂) based on tetrathiafulvalene derivatives and titanium dioxide with a micro/mesoporous nanomaterial structure has been synthesized via a facile sol-gel method. In this study, tetrathiafulvalene-3,4,5,6-tetrakis(4-benzoic acid) (H₄TTFTB) is an ideal electron-rich organic material and has been introduced into TiO₂ for promoting photocatalytic H₂ production under visible light irradiation. Notably, the optimized composites demonstrate remarkably enhanced photocatalytic H₂ evolution performance with a maximum H₂ evolution rate of 1452 μmol g⁻¹ h⁻¹, which is much higher than the prototypical counterparts, the common dye-sensitized sample (denoted as H₄TTFTB-5.0/TiO₂) (390.8 μmol g⁻¹ h⁻¹) and pure TiO₂ (18.87 μmol g⁻¹ h⁻¹). Moreover, the composites perform with excellent stability even after being used for seven time cycles. A series of characterizations of the morphological structure, the photoelectric physics performance and the photocatalytic activity of the hybrid reveal that the donor-acceptor structural H₄TTFTB and TiO₂ have been combined robustly by covalent titanium ester during the synthesis process, which improves the stability of the hybrid nanomaterials, extends visible-light adsorption range and stimulates the separation of photogenerated charges. This work provides new insight for regulating precisely the structure of the fulvalene-based composite at the molecule level and enhances our in-depth fundamental understanding of the photocatalytic mechanism. Full article

(This article belongs to the Special Issue Colloidal Semiconductor Nanostructures for Light-Harvesting and Beyond)

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19 pages, 8347 KiB

Open AccessArticle

Optimization of Sulfonated Polycatechol:PEDOT Energy Storage Performance by the Morphology Control

by Anatoliy A. Vereshchagin, Vasiliy V. Potapenkov, Petr S. Vlasov, Daniil A. Lukyanov and Oleg V. Levin

Nanomaterials 2022, 12(11), 1917; https://doi.org/10.3390/nano12111917 - 03 Jun 2022

Cited by 2 | Viewed by 1552

Abstract

Anionic catechol-containing polymers represent a promising class of functional dopants for the capacity improvement of conductive polymers. For example, sulfonated poly(vinylcatechol) SPVC with outstanding theoretical capacity was used as a dopant for poly(ethylenedixythiophene) (PEDOT) conductive polymer, increasing its energy storage performance. However, such [...] Read more.

Anionic catechol-containing polymers represent a promising class of functional dopants for the capacity improvement of conductive polymers. For example, sulfonated poly(vinylcatechol) SPVC with outstanding theoretical capacity was used as a dopant for poly(ethylenedixythiophene) (PEDOT) conductive polymer, increasing its energy storage performance. However, such materials suffer from insufficient utilization of the theoretical capacity of SPVC originating from non-optimal morphology. In the present study, we performed systematic optimization of the composition and morphology of the PEDOT:SPVC material as a function of the deposition parameters to overcome this problem. As a result, a capacity of 95 mAh·g⁻¹ was achieved in a thin film demonstrating considerable electrochemical stability: 75% capacity retention after 100 cycles and 57% after 1000 cycles. Since the capacity was found to suffer from thickness limitation, a nanocomposite of PEDOT:SPVC and single-walled carbon nanotubes with high PEDOT:SPVC loading was fabricated, yielding the capacitance 178 F·g⁻¹ or 89 F·cm⁻². The capacity values exceed non-optimized film twofold for thin film and 1.33 times for nanocomposite with carbon nanotubes. The obtained results demonstrate the importance of fine-tuning of the composition and morphology of the PEDOT:SPVC materials to ensure optimal interactions between the redox/anionic and conductive components. Full article

(This article belongs to the Special Issue Functional Nanostructured Materials—from Synthesis to Applications)

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