Nanomaterials

19 pages, 3243 KiB

Open AccessArticle

Theoretical Study of the Defects and Doping in Tuning the Electrocatalytic Activity of Graphene for CO₂ Reduction

by Xiao Su, Fanqi Meng, Xiang Li, Yueying Liu, Hongwei Tan and Guangju Chen

Nanomaterials 2023, 13(15), 2273; https://doi.org/10.3390/nano13152273 - 07 Aug 2023

Cited by 1 | Viewed by 1021

The application of graphene-based catalysts in the electrocatalytic CO₂ reduction reaction (ECO₂RR) for mitigating the greenhouse effect and energy shortage is a growing trend. The unique and extraordinary properties of graphene-based catalysts, such as low cost, high electrical conductivity, structural [...] Read more.

The application of graphene-based catalysts in the electrocatalytic CO₂ reduction reaction (ECO₂RR) for mitigating the greenhouse effect and energy shortage is a growing trend. The unique and extraordinary properties of graphene-based catalysts, such as low cost, high electrical conductivity, structural tunability, and environmental friendliness, have rendered them promising materials in this area. By doping heteroatoms or artificially inducing defects in graphene, its catalytic performance can be effectively improved. In this work, the mechanisms underlying the CO₂ reduction reaction on 10 graphene-based catalysts were systematically studied. N/B/O-codoped graphene with a single-atom vacancy defect showed the best performance and substantial improvement in catalytic activity compared with pristine graphene. The specific roles of the doped elements, including B, N, and O, as well as the defects, are discussed in detail. By analysing the geometric and electronic structures of the catalysts, we showed how the doped heteroatoms and defects influence the catalytic reaction process and synergistically promoted the catalytic efficiency of graphene. Full article

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12 pages, 2774 KiB

Open AccessArticle

Enhanced Lithium Storage Performance of α-MoO₃/CNTs Composite Cathode

by Dawei Sheng, Ang Gao, Xiaoxu Liu and Qiang Zhang

Nanomaterials 2023, 13(15), 2272; https://doi.org/10.3390/nano13152272 - 07 Aug 2023

Cited by 1 | Viewed by 769

Abstract

Orthorhombic molybdenum oxide (α-MoO₃), as a one-layered pseudocapacitive material, has attracted widespread attention due to its high theoretical lithium storage specific capacity (279 mAh/g) for lithium-ion batteries’ cathode. Nevertheless, low conductivity, slack reaction kinetics, and large volume change during Li⁺ [...] Read more.

Orthorhombic molybdenum oxide (α-MoO₃), as a one-layered pseudocapacitive material, has attracted widespread attention due to its high theoretical lithium storage specific capacity (279 mAh/g) for lithium-ion batteries’ cathode. Nevertheless, low conductivity, slack reaction kinetics, and large volume change during Li⁺ ions intercalation and deintercalation seriously limit the practical application of α-MoO₃. Herein, we added a small number of CNTs (1.76%) to solve these problems in a one-step hydrothermal process for preparing the α-MoO₃/CNTs composite. Because of the influence of CNTs, the α-MoO₃ nanobelt in the α-MoO₃/CNTs composite had a larger interlayer spacing, which provided more active sites and faster reaction kinetics for lithium storage. In addition, CNTs formed a three-dimensional conductive network between α-MoO₃ nanobelts, enhanced the electrical conductivity of the composite, accelerated the electron conduction, shortened the ion transport path, and alleviated the structural fragmentation caused by the volume expansion during the α-MoO₃ intercalation and deintercalation of Li⁺ ions. Therefore, the α-MoO₃/CNTs composite cathode had a significantly higher rate performance and cycle life. After 150 cycles, the pure α-MoO₃ cathode had almost no energy storage, but α-MoO₃/CNTs composite cathode still retained 93 mAh/g specific capacity. Full article

(This article belongs to the Special Issue Nanostructures for Wastewater Treatment and Energy Conversion)

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26 pages, 5625 KiB

Open AccessArticle

Methane Catalytic Combustion under Lean Conditions over Pristine and Ir-Loaded La_1−xSr_xMnO₃ Perovskites: Efficiency, Hysteresis, and Time-on-Stream and Thermal Aging Stabilities

by Catherine Drosou, Ersi Nikolaraki, Theodora Georgakopoulou, Sotiris Fanourgiakis, Vassilios T. Zaspalis and Ioannis V. Yentekakis

Nanomaterials 2023, 13(15), 2271; https://doi.org/10.3390/nano13152271 - 07 Aug 2023

Viewed by 967

Abstract

The increasing use of natural gas as an efficient, reliable, affordable, and cleaner energy source, compared with other fossil fuels, has brought the catalytic CH₄ complete oxidation reaction into the spotlight as a simple and economic way to control the amount of [...] Read more.

The increasing use of natural gas as an efficient, reliable, affordable, and cleaner energy source, compared with other fossil fuels, has brought the catalytic CH₄ complete oxidation reaction into the spotlight as a simple and economic way to control the amount of unconverted methane escaping into the atmosphere. CH₄ emissions are a major contributor to the ‘greenhouse effect’, and therefore, they need to be effectively reduced. Catalytic CH₄ oxidation is a promising method that can be used for this purpose. Detailed studies of the activity, oxidative thermal aging, and the time-on-stream (TOS) stability of pristine La_1−xSr_xMnO₃ perovskites (LS_XM; X = % substitution of La with Sr = 0, 30, 50 and 70%) and iridium-loaded Ir/La_1−xSr_xMnO₃ (Ir/LS_XM) perovskite catalysts were conducted in a temperature range of 400–970 °C to achieve complete methane oxidation under excess oxygen (lean) conditions. The effect of X on the properties of the perovskites, and thus, their catalytic performance during heating/cooling cycles, was studied using samples that were subjected to various pretreatment conditions in order to gain an in-depth understanding of the structure–activity/stability correlations. Large (up to ca. 300 °C in terms of T₅₀) inverted volcano-type differences in catalytic activity were found as a function of X, with the most active catalysts being those where X = 0%, and the least active were those where X = 50%. Inverse hysteresis phenomena (steady-state rate multiplicities) were revealed in heating/cooling cycles under reaction conditions, the occurrence of which was found to depend strongly on the employed catalyst pre-treatment (pre-reduction or pre-oxidation), while their shape and the loop amplitude were found to depend on X and the presence of Ir. All findings were consistently interpreted, which involved a two-term mechanistic model that utilized the synergy of Eley–Rideal and Mars–van Krevelen kinetics. Full article

(This article belongs to the Special Issue Advances in Nanomaterials for Energy Conversion and Environmental Catalysis)

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14 pages, 45200 KiB

Open AccessCommunication

Transport Property of Wrinkled Graphene Nanoribbon Tuned by Spin-Polarized Gate Made of Vanadium-Benzene Nanowire

by Hong Yu, Yan Shang, Yangyang Hu, Lei Pei and Guiling Zhang

Nanomaterials 2023, 13(15), 2270; https://doi.org/10.3390/nano13152270 - 07 Aug 2023

Viewed by 883

Abstract

A series of four-terminal V₇(Bz)₈-WGNR devices were established with wrinkled graphene nanoribbon (WGNR) and vanadium-benzene nanowire (V₇(Bz)₈). The spin-polarized V₇(Bz)₈ as the gate channel was placed crossing the plane, the concave (endo-positioned) [...] Read more.

A series of four-terminal V₇(Bz)₈-WGNR devices were established with wrinkled graphene nanoribbon (WGNR) and vanadium-benzene nanowire (V₇(Bz)₈). The spin-polarized V₇(Bz)₈ as the gate channel was placed crossing the plane, the concave (endo-positioned) and the convex (endo-positioned) surface of WGNR with different curvatures via Van der Waals interaction. The density functional theory (DFT) and nonequilibrium Green’s function (NEGF) methods were adopted to calculate the transport properties of these devices at various bias voltages (V_S) and gate voltages (V_G), such as the conductance, spin-polarized currents, transmission spectra (TS), local density of states (LDOS), and scattering states. The results indicate that the position of V₇(Bz)₈ and the bending curvature of WGNR play important roles in tuning the transport properties of these four-terminal devices. A spin-polarized transport property is induced for these four-terminal devices by the spin-polarized nature of V₇(Bz)₈. Particularly, the down-spin channel disturbs strongly on the source-to-drain conductance of WGNR when V₇(Bz)₈ is endo-positioned crossing the WGNR. Our findings on the novel property of four-terminal V₇(Bz)₈-WGNR devices provide useful guidelines for achieving flexible graphene-based electronic nanodevices by attaching other similar multidecker metal-arene nanowires. Full article

(This article belongs to the Special Issue Current Advances in Nanoelectronics, Nanosensors and Devices)

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29 pages, 8256 KiB

Open AccessReview

Recent Progress of Photothermal Therapy Based on Conjugated Nanomaterials in Combating Microbial Infections

by Yue Zhao, Yi Wang, Xiaoyu Wang, Ruilian Qi and Huanxiang Yuan

Nanomaterials 2023, 13(15), 2269; https://doi.org/10.3390/nano13152269 - 07 Aug 2023

Cited by 4 | Viewed by 1576

Abstract

Photothermal therapy has the advantages of non-invasiveness, low toxicity, simple operation, a broad spectrum of antibacterial ability, and non-proneness to developing drug resistance, which provide it with irreplaceable superiority in fighting against microbial infection. The effect of photothermal therapy is closely related to [...] Read more.

Photothermal therapy has the advantages of non-invasiveness, low toxicity, simple operation, a broad spectrum of antibacterial ability, and non-proneness to developing drug resistance, which provide it with irreplaceable superiority in fighting against microbial infection. The effect of photothermal therapy is closely related to the choice of photothermal agent. Conjugated nanomaterials are potential candidates for photothermal agents because of their easy modification, excellent photothermal conversion efficiency, good photostability, and biodegradability. In this paper, the application of photothermal agents based on conjugated nanomaterials in photothermal antimicrobial treatment is reviewed, including conjugated small molecules, conjugated oligomers, conjugated polymers, and pseudo-conjugated polymers. At the same time, the application of conjugated nanomaterials in the combination of photothermal therapy (PTT) and photodynamic therapy (PDT) is briefly introduced. Finally, the research status, limitations, and prospects of photothermal therapy using conjugated nanomaterials as photothermal agents are discussed. Full article

(This article belongs to the Special Issue Applications of Smart Nanomaterials)

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10 pages, 4602 KiB

Open AccessCommunication

Controlled Fabrication of Hierarchically Structured MnO₂@NiCo-LDH Nanoarrays for Efficient Electrocatalytic Urea Oxidization

by Wenjun Liu, Wenbo Xu, Guofa Dong and Ming Fang

Nanomaterials 2023, 13(15), 2268; https://doi.org/10.3390/nano13152268 - 07 Aug 2023

Viewed by 909

Abstract

Urea, a prevalent component found in wastewater, shows great promise as a substrate for energy-efficient hydrogen production by electrolysis. However, the slow kinetics of the anodic urea oxidation reaction (UOR) significantly hamper the overall reaction rate. This study presents the design and controlled [...] Read more.

Urea, a prevalent component found in wastewater, shows great promise as a substrate for energy-efficient hydrogen production by electrolysis. However, the slow kinetics of the anodic urea oxidation reaction (UOR) significantly hamper the overall reaction rate. This study presents the design and controlled fabrication of hierarchically structured nanomaterials as potential catalysts for UOR. The prepared MnO₂@NiCo-LDH hybrid catalyst demonstrates remarkable improvements in reaction kinetics, benefiting from synergistic enhancements in charge transfer and efficient mass transport facilitated by its unique hierarchical architecture. Notably, the catalyst exhibits an exceptionally low onset potential of 1.228 V and requires only 1.326 V to achieve an impressive current density of 100 mA cm⁻², representing a state-of-the-art performance in UORs. These findings highlight the tremendous potential of this innovative material designing strategy to drive advancements in electrocatalytic processes. Full article

(This article belongs to the Section Energy and Catalysis)

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28 pages, 8485 KiB

Open AccessReview

Intensity-Dependent Optical Response of 2D LTMDs Suspensions: From Thermal to Electronic Nonlinearities

by Anderson S. L. Gomes, Cecília L. A. V. Campos, Cid B. de Araújo, Melissa Maldonado, Manoel L. da Silva-Neto, Ali M. Jawaid, Robert Busch and Richard A. Vaia

Nanomaterials 2023, 13(15), 2267; https://doi.org/10.3390/nano13152267 - 07 Aug 2023

Viewed by 1040

Abstract

The nonlinear optical (NLO) response of photonic materials plays an important role in the understanding of light–matter interaction as well as pointing out a diversity of photonic and optoelectronic applications. Among the recently studied materials, 2D-LTMDs (bi-dimensional layered transition metal dichalcogenides) have appeared [...] Read more.

The nonlinear optical (NLO) response of photonic materials plays an important role in the understanding of light–matter interaction as well as pointing out a diversity of photonic and optoelectronic applications. Among the recently studied materials, 2D-LTMDs (bi-dimensional layered transition metal dichalcogenides) have appeared as a beyond-graphene nanomaterial with semiconducting and metallic optical properties. In this article, we review most of our work in studies of the NLO response of a series of 2D-LTMDs nanomaterials in suspension, using six different NLO techniques, namely hyper Rayleigh scattering, Z-scan, photoacoustic Z-scan, optical Kerr gate, and spatial self-phase modulation, besides the Fourier transform nonlinear optics technique, to infer the nonlinear optical response of semiconducting MoS₂, MoSe₂, MoTe₂, WS₂, semimetallic WTe₂, ZrTe₂, and metallic NbS₂ and NbSe₂. The nonlinear optical response from a thermal to non-thermal origin was studied, and the nonlinear refraction index and nonlinear absorption coefficient, where present, were measured. Theoretical support was given to explain the origin of the nonlinear responses, which is very dependent on the spectro-temporal regime of the optical source employed in the studies. Full article

(This article belongs to the Special Issue Advances in Photonic and Plasmonic Nanomaterials—Volume II)

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12 pages, 3484 KiB

Open AccessArticle

Synergistic Effect of Y Doping and Reduction of TiO₂ on the Improvement of Photocatalytic Performance

by Xijuan Li, Hongjuan Zheng, Yulong Wang, Xia Li, Jinsong Liu, Kang Yan, Jing Wang and Kongjun Zhu

Nanomaterials 2023, 13(15), 2266; https://doi.org/10.3390/nano13152266 - 07 Aug 2023

Cited by 2 | Viewed by 968

Abstract

Pure TiO₂ and 3% Y-doped TiO₂ (3% Y-TiO₂) were prepared by a one-step hydrothermal method. Reduced TiO₂ (TiO₂-H₂) and 3% Y-TiO₂ (3% Y-TiO₂-H₂) were obtained through the thermal conversion [...] Read more.

Pure TiO₂ and 3% Y-doped TiO₂ (3% Y-TiO₂) were prepared by a one-step hydrothermal method. Reduced TiO₂ (TiO₂-H₂) and 3% Y-TiO₂ (3% Y-TiO₂-H₂) were obtained through the thermal conversion treatment of Ar-H₂ atmosphere at 500 °C for 3 h. By systematically comparing the crystalline phase, structure, morphological features, and photocatalytic properties of 3% Y-TiO₂-H₂ with pure TiO₂, 3% Y-TiO₂, and TiO₂-H₂, the synergistic effect of Y doping and reduction of TiO₂ was obtained. All samples show the single anatase phase, and no diffraction peak shift is observed. Compared with single-doped TiO₂ and single-reduced TiO₂, 3% Y-TiO₂-H₂ exhibits the best photocatalytic performance for the degradation of RhB, which can be totally degraded in 20 min. The improvement of photocatalytic performance was attributed to the synergistic effect of Y doping and reduction treatment. Y doping broadened the range of light absorption and reduced the charge recombination rates, and the reduction treatment caused TiO₂ to be enveloped by disordered shells. The remarkable feature of reduced TiO₂ by H₂ is its disordered shell filled with a limited amount of oxygen vacancies (O_Vs) or Ti³⁺, which significantly reduces the E_g of TiO₂ and remarkably increases the absorption of visible light. The synergistic effect of Y doping, Ti³⁺ species, and O_Vs play an important role in the improvement of photocatalytic performances. The discovery of this work provides a new perspective for the improvement of other photocatalysts by combining doping and reduction to modify traditional photocatalytic materials and further improve their performance. Full article

(This article belongs to the Section Energy and Catalysis)

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12 pages, 3655 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Nanobubble Water Containing Cordyceps Extract and Withaferin A on Free Fatty Acid-Induced Lipid Accumulation in HepG2 Cells

by Hanlin Han, Yixin Sun, Weixu Zhang, Zhenya Zhang and Tian Yuan

Nanomaterials 2023, 13(15), 2265; https://doi.org/10.3390/nano13152265 - 07 Aug 2023

Viewed by 1044

Abstract

Cordyceps extract and withaferin A (Wi-A) are natural compounds that have therapeutic effects on non-alcoholic fatty liver disease (NAFLD). However, their efficacy is limited and a long treatment duration is usually required. To enhance their efficiency, the synergistic effects of nanobubble water (NBW) [...] Read more.

Cordyceps extract and withaferin A (Wi-A) are natural compounds that have therapeutic effects on non-alcoholic fatty liver disease (NAFLD). However, their efficacy is limited and a long treatment duration is usually required. To enhance their efficiency, the synergistic effects of nanobubble water (NBW) derived from nitrogen, hydrogen, and oxygen gases were investigated. Results showed that the physical properties of all three NBWs, including nanobubble density (10⁸ particles/mL) and zeta potential (below −22 mV), were stable during 48 h of storage. Hydrogen and nitrogen NBWs did not reduce, but instead promoted, free fatty acid-induced lipid accumulation in HepG2 cells. In contrast, oxygen NBW synergistically enhanced the effects of cordyceps extract and Wi-A. The lipid content decreased by 29% and 33% in the oxygen NBW + cordyceps extract and oxygen NBW + Wi-A groups, respectively, compared to reductions of 22% and 16% by aqueous extracts without NB. This study found that NBW may enhance the lipid-reducing effects of natural compounds, such as cordyceps extract and withaferin A, in hepatic cells. Further studies in animal experiments are needed to determine whether NBW has a potential application in NAFLD. Full article

(This article belongs to the Special Issue Micro/Nanobubbles for Biomedical Applications)

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12 pages, 5959 KiB

Open AccessArticle

Study on Oxygen Evolution Reaction of Ir Nanodendrites Supported on Antimony Tin Oxide

by Yu-Chun Chiang, Zhi-Hui Pu and Ziyi Wang

Nanomaterials 2023, 13(15), 2264; https://doi.org/10.3390/nano13152264 - 07 Aug 2023

Cited by 1 | Viewed by 1101

Abstract

In this study, the iridium nanodendrites (Ir NDs) and antimony tin oxide (ATO)-supported Ir NDs (Ir ND/ATO) were prepared by a surfactant-mediated method to investigate the effect of ATO support and evaluate the electrocatalytic activity for the oxygen evolution reaction (OER). The nano-branched [...] Read more.

In this study, the iridium nanodendrites (Ir NDs) and antimony tin oxide (ATO)-supported Ir NDs (Ir ND/ATO) were prepared by a surfactant-mediated method to investigate the effect of ATO support and evaluate the electrocatalytic activity for the oxygen evolution reaction (OER). The nano-branched Ir ND structures were successfully prepared alone or supported on ATO. The Ir NDs exhibited major diffraction peaks of the fcc Ir metal, though the Ir NDs consisted of metallic Ir as well as Ir oxides. Among the Ir ND samples, Ir ND2 showed the highest mass-based OER catalytic activity (116 mA/mg at 1.8 V), while it suffered from high degradation in activity after a long-term test. On the other hand, Ir ND2/ATO had OER activity of 798 mA/mg, and this activity remained >99% after 100 cycles of LSV and the charge transfer resistance increased by less than 3 ohm. The enhanced durability of the OER mass activities of Ir ND2/ATO catalysts over Ir NDs and Ir black could be attributed to the small crystallite size of Ir and the increase in the ratio of Ir (III) to Ir (IV), improving the interactions between the Ir NDs and the ATO support. Full article

(This article belongs to the Special Issue Nanomaterials for Chemical Engineering (Volume II))

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16 pages, 5384 KiB

Open AccessArticle

Temperature-Dependent Optical Properties of Oxidized Graphenes

by Talia Tene, Paola G. Vinueza-Naranjo, Yesenia Cevallos, Fabian Arias Arias, Matteo La Pietra, Andrea Scarcello, Yolenny Cruz Salazar, Melvin Arias Polanco, Salvatore Straface, Cristian Vacacela Gomez, Lorenzo S. Caputi and Stefano Bellucci

Nanomaterials 2023, 13(15), 2263; https://doi.org/10.3390/nano13152263 - 07 Aug 2023

Cited by 1 | Viewed by 929

Abstract

In this study, we investigate how changing important synthesis-related parameters can affect and control the optical characteristics of graphene oxide (GO) and reduced graphene oxide (rGO). These parameters include drying time and reduction time at two different temperatures. We obtain an understanding of [...] Read more.

In this study, we investigate how changing important synthesis-related parameters can affect and control the optical characteristics of graphene oxide (GO) and reduced graphene oxide (rGO). These parameters include drying time and reduction time at two different temperatures. We obtain an understanding of their impact on optical transitions, optical bandgap, absorption coefficient, and absorbance spectrum width by analyzing these factors. Accordingly, GO has an optical bandgap of about 4 eV, which is decreased by the reduction process to 1.9 eV. Both GO and rGO display greater absorption in the visible spectrum, which improves photon capture and boosts efficiency in energy conversion applications. Additionally, our results show that GO and rGO have higher absorption coefficients than those previously reported for dispersions of exfoliated graphene. Defects in GO and rGO, as well as the presence of functional oxygen groups, are the main contributors to this increased absorption. Several measurements are carried out, including spectroscopic and morphological studies, to further support our findings. Full article

(This article belongs to the Special Issue Functional Graphene-Based Nanodevices)

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14 pages, 4012 KiB

Open AccessArticle

One-Pot Mechanochemical Synthesis of Carbons with High Microporosity and Ordered Mesopores for CO₂ Uptake at Ambient Conditions

by Rabindra Dubadi and Mietek Jaroniec

Nanomaterials 2023, 13(15), 2262; https://doi.org/10.3390/nano13152262 - 07 Aug 2023

Cited by 4 | Viewed by 1315

Abstract

Mechanochemical synthesis of ordered mesoporous carbons with tunable mesopores and well-developed irregular microporosity is investigated. This synthesis was carried out by the self-assembly of ecofriendly chemicals such as tannin and glyoxal used as carbon precursors, and triblock copolymer as a soft templating agent. [...] Read more.

Mechanochemical synthesis of ordered mesoporous carbons with tunable mesopores and well-developed irregular microporosity is investigated. This synthesis was carried out by the self-assembly of ecofriendly chemicals such as tannin and glyoxal used as carbon precursors, and triblock copolymer as a soft templating agent. The structural properties of the resulting carbons were tailored by using different block copolymers (Pluronic F127, and P123) as soft templates. The various weight ratios of tannin and block copolymer were employed to tune the textural properties of these carbons. The tannin: Pluronic F127 ratios (1:0.75, 1:1, 1:1.1) gave the ordered mesoporous carbons among a wide variety of the samples studied. The ordered mesoporosity was not observed in the case of Pluronic P123 templated mesoporous carbons. The CO₂-activated carbon samples obtained for both Pluronic templates showed a high specific surface area (close to 900 m²/g), large pore volume (about 0.6–0.7 cm³g⁻¹), narrow pore size distribution, and high CO₂ uptake of about 3.0 mmol g⁻¹ at 1 bar pressure and ambient temperature. Full article

(This article belongs to the Special Issue Nanomaterials toward CO₂ Reduction and Conversion)

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13 pages, 5943 KiB

Open AccessArticle

In Situ Growth of CdZnS Nanoparticles@Ti₃C₂T_x MXene Nanosheet Heterojunctions for Boosted Visible-Light-Driven Photocatalytic Hydrogen Evolution

by Zelin Li, Yang Zhao, Qinglin Deng, Xuhui Zhu, Yipeng Tan, Ziwen Feng, Hao Ji, Shan Zhang and Lingmin Yao

Nanomaterials 2023, 13(15), 2261; https://doi.org/10.3390/nano13152261 - 06 Aug 2023

Viewed by 1387

Abstract

Using natural light energy to convert water into hydrogen is of great significance to solving energy shortages and environmental pollution. Due to the rapid recombination of photogenerated carriers after separation, the efficiency of photocatalytic hydrogen production using photocatalysts is usually very low. Here, [...] Read more.

Using natural light energy to convert water into hydrogen is of great significance to solving energy shortages and environmental pollution. Due to the rapid recombination of photogenerated carriers after separation, the efficiency of photocatalytic hydrogen production using photocatalysts is usually very low. Here, efficient CdZnS nanoparticles@Ti₃C₂T_x MXene nanosheet heterojunction photocatalysts have been successfully prepared by a facile in situ growth strategy. Since the CdZnS nanoparticles uniformly covered the Ti₃C₂T_x Mxene nanosheets, the agglomeration phenomenon of CdZnS nanoparticles could be effectively inhibited, accompanied by increased Schottky barrier sites and an enhanced migration rate of photogenerated carriers. The utilization efficiency of light energy can be improved by inhibiting the recombination of photogenerated electron-hole pairs. As a result, under the visible-light-driven photocatalytic experiments, this composite achieved a high hydrogen evolution rate of 47.1 mmol h⁻¹ g⁻¹, which is much higher than pristine CdZnS and Mxene. The boosted photocatalytic performances can be attributed to the formed heterojunction of CdZnS nanoparticles and Ti₃C₂T_x MXene nanosheets, as well as the weakened agglomeration effects. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Photocatalysis)

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17 pages, 2206 KiB

Open AccessArticle

Plant Photocatalysts: Photoinduced Oxidation and Reduction Abilities of Plant Leaf Ashes under Solar Light

by Xiaoqian Ma, Jiao He, Yu Liu, Xiaoli Bai, Junyang Leng, Yi Zhao, Daomei Chen and Jiaqiang Wang

Nanomaterials 2023, 13(15), 2260; https://doi.org/10.3390/nano13152260 - 06 Aug 2023

Cited by 2 | Viewed by 1396

Abstract

Plant leaf ashes were obtained via the high temperature calcination of the leaves of various plants, such as sugarcane, couchgrass, bracteata, garlic sprout, and the yellowish leek. Although the photosynthesis systems in plant leaves cannot exist after calcination, minerals in these ashes were [...] Read more.

Plant leaf ashes were obtained via the high temperature calcination of the leaves of various plants, such as sugarcane, couchgrass, bracteata, garlic sprout, and the yellowish leek. Although the photosynthesis systems in plant leaves cannot exist after calcination, minerals in these ashes were found to exhibit photochemical activities. The samples showed solar light photocatalytic oxidation activities sufficient to degrade methylene blue dye. They were also shown to possess intrinsic dehydrogenase-like activities in reducing the colorless electron acceptor 2,3,5-triphenyltetrazolium chloride to a red formazan precipitate under solar light irradiation. The possible reasons behind these two unreported phenomena were also investigated. These ashes were characterized using a combination of physicochemical techniques. Moreover, our findings exemplify how the soluble and insoluble minerals in plant leaf ashes can be synergistically designed to yield next-generation photocatalysts. It may also lead to advances in artificial photosynthesis and photocatalytic dehydrogenase. Full article

(This article belongs to the Special Issue Nanomaterials for Catalytic Pollutant Destruction)

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11 pages, 4641 KiB

Open AccessArticle

Boosting the Self-Trapped Exciton Emission in Cs₄SnBr₆ Zero-Dimensional Perovskite via Rapid Heat Treatment

by Haixia Wu, Zhenxu Lin, Jie Song, Yi Zhang, Yanqing Guo, Wenxing Zhang and Rui Huang

Nanomaterials 2023, 13(15), 2259; https://doi.org/10.3390/nano13152259 - 06 Aug 2023

Cited by 2 | Viewed by 1122

Abstract

Zero-dimensional (0D) tin halide perovskites feature extraordinary properties, such as broadband emission, high photoluminescence quantum yield, and self-absorption-free characteristics. The innovation of synthesis approaches for high-quality 0D tin halide perovskites has facilitated the flourishing development of perovskite-based optoelectronic devices in recent years. However, [...] Read more.

Zero-dimensional (0D) tin halide perovskites feature extraordinary properties, such as broadband emission, high photoluminescence quantum yield, and self-absorption-free characteristics. The innovation of synthesis approaches for high-quality 0D tin halide perovskites has facilitated the flourishing development of perovskite-based optoelectronic devices in recent years. However, discovering an effective strategy to further enhance their emission efficiency remains a considerable challenge. Herein, we report a unique strategy employing rapid heat treatment to attain efficient self-trapped exciton (STE) emission in Cs₄SnBr₆ zero-dimensional perovskite. Compared to the pristine Cs₄SnBr₆, rapid thermal treatment (RTT) at 200 °C for a duration of 120 s results in an augmented STE emission with the photoluminescence (PL) quantum yield rising from an initial 50.1% to a substantial 64.7%. Temperature-dependent PL spectra analysis, Raman spectra, and PL decay traces reveal that the PL improvement is attributed to the appropriate electron–phonon coupling as well as the increased binding energies of STEs induced by the RTT. Our findings open up a new avenue for efficient luminescent 0D tin-halide perovskites toward the development of efficient optoelectronic devices based on 0D perovskites. Full article

(This article belongs to the Special Issue Luminescent Nanomaterials: Functional Design, Advantages, and Applications)

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18 pages, 4311 KiB

Open AccessArticle

Biobased Electronics: Tunable Dielectric and Piezoelectric Cellulose Nanocrystal—Protein Films

by Daniel Voignac, Shylee Belsey, Elisabeth Wermter, Yossi Paltiel and Oded Shoseyov

Nanomaterials 2023, 13(15), 2258; https://doi.org/10.3390/nano13152258 - 06 Aug 2023

Viewed by 1585

Abstract

Cellulose has been a go-to material for its dielectric properties from the onset of capacitor development. The demand for an energy storage solution continues to grow, but the supply remains limited and relies too often on fossil and mined materials. This work proposes [...] Read more.

Cellulose has been a go-to material for its dielectric properties from the onset of capacitor development. The demand for an energy storage solution continues to grow, but the supply remains limited and relies too often on fossil and mined materials. This work proposes a fully sustainable and green method with which to produce dielectric thin films made of renewable and degradable materials. Cellulose nanocrystals (CNC) made an excellent matrix for the dispersion of proteins and the fabrication of robust transparent thin films with enhanced dielectric permittivity. A range of proteins sources, additives and concentrations allowed for us to control the dielectric permittivity from ε_r = 4 to 50. The proteins screened came from animal and plant sources. The films were formed from drying a water suspension of the CNC and proteins through evaporation-induced self-assembly. This yielded nano-layered structures with very high specific surface areas, ideal for energy storage devices. The resulting films were characterized with respect to the electrical, mechanical, piezoelectric, and optical properties to be compared. Electrically conductive (σ = 1.53 × 10³ S/m) CNC films were prepared with carbon nanotubes (CNT). The fabricated films were used to make flexible, sustainable, and degradable capacitors by layering protein-based films between CNC–CNT composite films. Full article

(This article belongs to the Special Issue Advanced Nanocellulose-Based Materials: Production, Properties and Applications II)

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12 pages, 5450 KiB

Open AccessArticle

Antimony Selenide Solar Cells Fabricated by Hybrid Reactive Magnetron Sputtering

by Daniel Brito, Pedro Anacleto, Ana Pérez-Rodríguez, José Fonseca, Pedro Santos, Marina Alves, Alessandro Cavalli, Deepanjan Sharma, Marcel S. Claro, Nicoleta Nicoara and Sascha Sadewasser

Nanomaterials 2023, 13(15), 2257; https://doi.org/10.3390/nano13152257 - 05 Aug 2023

Cited by 2 | Viewed by 1198

Abstract

The fabrication of Sb₂Se₃ thin-film solar cells deposited by a pulsed hybrid reactive magnetron sputtering (PHRMS) was proposed and examined for different growth conditions. The influence of growth temperature and Se pulse period were studied in terms of morphology, crystal [...] Read more.

The fabrication of Sb₂Se₃ thin-film solar cells deposited by a pulsed hybrid reactive magnetron sputtering (PHRMS) was proposed and examined for different growth conditions. The influence of growth temperature and Se pulse period were studied in terms of morphology, crystal structure, and composition. The Sb₂Se₃ growth showed to be dependent on the growth temperature, with a larger crystal size for growth at 270 °C. By controlling the Se pulse period, the crystal structure and crystal size could be modified as a function of the supplied Se amount. The solar cell performance for Sb₂Se₃ absorbers deposited at various temperatures, Se pulse periods and thicknesses were assessed through current-voltage characteristics. A power conversion efficiency (PCE) of 3.7% was achieved for a Sb₂Se₃ solar cell with 900 nm thickness, Sb₂Se₃ deposited at 270 °C and Se pulses with 0.1 s duration and period of 0.5 s. Finally, annealing the complete solar cell at 100 °C led to a further improvement of the V_oc, leading to a PCE of 3.8%, slightly higher than the best reported Sb₂Se₃ solar cell prepared by sputtering without post-selenization. Full article

(This article belongs to the Topic Thin-Film Photovoltaics: Constituents and Devices)

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15 pages, 2379 KiB

Open AccessArticle

Laser-Ablative Synthesis of Silicon–Iron Composite Nanoparticles for Theranostic Applications

by Alexander A. Bubnov, Vladimir S. Belov, Yulia V. Kargina, Gleb V. Tikhonowski, Anton A. Popov, Alexander Yu. Kharin, Mikhail V. Shestakov, Alexander M. Perepukhov, Alexander V. Syuy, Valentyn S. Volkov, Vladimir V. Khovaylo, Sergey M. Klimentov, Andrei V. Kabashin and Victor Yu. Timoshenko

Nanomaterials 2023, 13(15), 2256; https://doi.org/10.3390/nano13152256 - 05 Aug 2023

Cited by 2 | Viewed by 1396

Abstract

The combination of photothermal and magnetic functionalities in one biocompatible nanoformulation forms an attractive basis for developing multifunctional agents for biomedical theranostics. Here, we report the fabrication of silicon–iron (Si-Fe) composite nanoparticles (NPs) for theranostic applications by using a method of femtosecond laser [...] Read more.

The combination of photothermal and magnetic functionalities in one biocompatible nanoformulation forms an attractive basis for developing multifunctional agents for biomedical theranostics. Here, we report the fabrication of silicon–iron (Si-Fe) composite nanoparticles (NPs) for theranostic applications by using a method of femtosecond laser ablation in acetone from a mixed target combining silicon and iron. The NPs were then transferred to water for subsequent biological use. From structural analyses, it was shown that the formed Si-Fe NPs have a spherical shape and sizes ranging from 5 to 150 nm, with the presence of two characteristic maxima around 20 nm and 90 nm in the size distribution. They are mostly composed of silicon with the presence of a significant iron silicide content and iron oxide inclusions. Our studies also show that the NPs exhibit magnetic properties due to the presence of iron ions in their composition, which makes the formation of contrast in magnetic resonance imaging (MRI) possible, as it is verified by magnetic resonance relaxometry at the proton resonance frequency. In addition, the Si-Fe NPs are characterized by strong optical absorption in the window of relative transparency of bio-tissue (650–950 nm). Benefiting from such absorption, the Si-Fe NPs provide strong photoheating in their aqueous suspensions under continuous wave laser excitation at 808 nm. The NP-induced photoheating is described by a photothermal conversion efficiency of 33–42%, which is approximately 3.0–3.3 times larger than that for pure laser-synthesized Si NPs, and it is explained by the presence of iron silicide in the NP composition. Combining the strong photothermal effect and MRI functionality, the synthesized Si-Fe NPs promise a major advancement of modalities for cancer theranostics, including MRI-guided photothermal therapy and surgery. Full article

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

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15 pages, 4953 KiB

Open AccessArticle

Investigation of Structural, Morphological, and Optical Properties of Novel Electrospun Mg-Doped TiO₂ Nanofibers as an Electron Transport Material for Perovskite Solar Cells

by Kubra Erdogar, Ozgun Yucel and Muhammed Enes Oruc

Nanomaterials 2023, 13(15), 2255; https://doi.org/10.3390/nano13152255 - 05 Aug 2023

Cited by 1 | Viewed by 1022

Abstract

Perovskite solar cells (PSCs) are quickly becoming efficient solar cells due to the effective physicochemical properties of the absorber layer. This layer should ideally be placed between a stable hole transport material (HTM) layer and a conductive electron transport material (ETM) layer. These [...] Read more.

Perovskite solar cells (PSCs) are quickly becoming efficient solar cells due to the effective physicochemical properties of the absorber layer. This layer should ideally be placed between a stable hole transport material (HTM) layer and a conductive electron transport material (ETM) layer. These outer layers play a critical role in the current densities and cell voltages of solar cells. In this work, we successfully fabricated Mg-doped TiO₂ nanofibers as ETM layers via electrospinning. This study systematically investigates the morphological and optical features of Mg-doped nanofibers as mesoporous ETM layers. The existence of the Mg element in the lattice was confirmed by XRD and XPS. These optical characterizations indicated that Mg doping widened the energy band gap and shifted the edge of the conduction band minimum upward, which enhanced the open circuit voltage (V_oc) and short current density (J_sc). The electron-hole recombination rate was lowered, and separation efficiency increased with Mg doping. The results have demonstrated the possibility of improving the efficiency of PSCs with the use of Mg-doped nanofibers as an ETM layer. Full article

(This article belongs to the Section Solar Energy and Solar Cells)

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11 pages, 5529 KiB

Open AccessArticle

Tailing Optical Pulling Force on a Metal–Dielectric Hybrid Dimer with Electromagnetic Coupling

by Xiao-Ming Zhang, Jin-Jing Yu, Hai-Ping Wu, Xia Zhou, Tian-Yue Zhang and Jian-Ping Liu

Nanomaterials 2023, 13(15), 2254; https://doi.org/10.3390/nano13152254 - 05 Aug 2023

Viewed by 907

Abstract

In this work, we demonstrate that optical pulling forces (OPFs) can be induced by a hybrid dimer consisting of a Si nanoparticle (NP) and a coated nanoparticle with a gain core and Au shell under normal plane wave illumination. Analytical theory reveals that [...] Read more.

In this work, we demonstrate that optical pulling forces (OPFs) can be induced by a hybrid dimer consisting of a Si nanoparticle (NP) and a coated nanoparticle with a gain core and Au shell under normal plane wave illumination. Analytical theory reveals that the underlying physical mechanism relies on interactions between the electric dipole (ED) modes excited in the NPs. As compared with the individual NP, it is found that the magnitude of optical force can be enlarged by almost three orders for the Si NP and one order for the coated gain NP in the coupled dimer. In addition, we find that the OPFs exerted on the NPs are heavily dependent on the gain level of the core materials, the incident polarization angle and the sizes of the NPs. More interestingly, we find that the OPF can also be exerted on a trimer system consisting of two identical Si NPs and a coated NP arranged in a line. The related results could be used to propose a versatile platform for manipulating NPs. Full article

(This article belongs to the Section Theory and Simulation of Nanostructures)

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10 pages, 2484 KiB

Open AccessArticle

Enhancing Light Extraction Efficiency in OLED Using Scattering Structure-Embedded DMD-Based Transparent Composite Electrodes

by Geun-Su Choi, Eun-Jeong Bae, Byeong-Kwon Ju and Young-Wook Park

Nanomaterials 2023, 13(15), 2253; https://doi.org/10.3390/nano13152253 - 05 Aug 2023

Cited by 1 | Viewed by 1460

Abstract

This study investigates the application of scattering structures to the metal layer in a DMD (Dielectric/Metal/Dielectric) configuration through plasma treatment. The purpose is to enhance the light extraction efficiency of organic light-emitting diodes (OLEDs). Different plasma conditions were explored to create scattering structures [...] Read more.

This study investigates the application of scattering structures to the metal layer in a DMD (Dielectric/Metal/Dielectric) configuration through plasma treatment. The purpose is to enhance the light extraction efficiency of organic light-emitting diodes (OLEDs). Different plasma conditions were explored to create scattering structures on the metal layer. The fabricated devices were characterized for their electrical and optical properties. The results demonstrate that the introduction of scattering structures through plasma treatment effectively improves the light extraction efficiency of OLEDs. Specifically, using O₂-plasma treatment on the metal layer resulted in significant enhancements in the total transmittance, haze, and figure of merit. These findings suggest that incorporating scattering structures within the DMD configuration can effectively promote light extraction in OLEDs, leading to enhanced overall performance and light efficiency. Full article

(This article belongs to the Special Issue Multifunctional Materials and Applications: Basic Nanomaterials, Catalysis, Composite, Electronic and Biomaterials)

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13 pages, 3597 KiB

Open AccessArticle

Enhanced Thermochromic Performance of VO₂ Nanoparticles by Quenching Process

by Senwei Wu, Longxiao Zhou, Bin Li, Shouqin Tian and Xiujian Zhao

Nanomaterials 2023, 13(15), 2252; https://doi.org/10.3390/nano13152252 - 04 Aug 2023

Cited by 1 | Viewed by 914

Abstract

Vanadium dioxide (VO₂) has been a promising energy-saving material due to its reversible metal-insulator transition (MIT) performance. However, the application of VO₂ films has been seriously restricted due to the intrinsic low solar-energy modulation ability (ΔT_sol) and [...] Read more.

Vanadium dioxide (VO₂) has been a promising energy-saving material due to its reversible metal-insulator transition (MIT) performance. However, the application of VO₂ films has been seriously restricted due to the intrinsic low solar-energy modulation ability (ΔT_sol) and low luminous transmittance (T_lum) of VO₂. In order to solve the problems, the surface structure of VO₂ particles was regulated by the quenching process and the VO₂ dispersed films were fabricated by spin coating. Characterizations showed that the VO₂ particles quenched in deionized water or ethanolreserved VO₂(M) phase structure and they were accompanied by surface lattice distortion compared to the pristine VO₂. Such distortion structure contributed to less aggregation and highly individual dispersion of the quenched particles in nanocomposite films. The corresponding film of VO₂ quenched in water exhibited much higher ΔT_sol with an increment of 42.5% from 8.8% of the original VO₂ film, because of the significant localized surface plasmon resonance (LSPR) effect. The film fabricated from the VO₂ quenched in ethanol presented enhanced thermochromic properties with 15.2% of ΔT_sol and 62.5% of T_lum. It was found that the excellent T_lum resulted from the highly uniform dispersion state of the quenched VO₂ nanoparticles. In summary, the study provided a facile way to fabricate well-dispersed VO₂ nanocomposite films and to facilitate the industrialization development of VO₂ thermochromic films in the smart window field. Full article

(This article belongs to the Special Issue Nanocomposite Design for Energy-Related Applications)

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13 pages, 2702 KiB

Open AccessArticle

Chiral Mechanical Effect of the Tightly Focused Chiral Vector Vortex Fields Interacting with Particles

by Qiang Zhang, Zhirong Liu and Ziqiang Cheng

Nanomaterials 2023, 13(15), 2251; https://doi.org/10.3390/nano13152251 - 04 Aug 2023

Viewed by 846

Abstract

The coupling of the spin-orbit angular momentum of photons in a focused spatial region can enhance the localized optical field’s chirality. In this paper, a scheme for producing a superchiral optical field in a 4

π

microscopic system is presented by tightly focusing [...] Read more.

The coupling of the spin-orbit angular momentum of photons in a focused spatial region can enhance the localized optical field’s chirality. In this paper, a scheme for producing a superchiral optical field in a 4

π

microscopic system is presented by tightly focusing two counter-propagating spiral wavefronts. We calculate the optical forces and torques exerted on a chiral dipole by the chiral light field and reveal the chiral forces by combining the light field and dipoles. Results indicate that, in addition to the general optical force, particles’ motion would be affected by a chiral force that is directly related to the particle chirality. This chiral mechanical effect experienced by the electromagnetic dipoles excited on a chiral particle could be characterized by the behaviors of chirality density and flux, which are, respectively, associated with the reactive and dissipative components of the chiral forces. This work facilitates the advancement of optical separation and manipulation techniques for chiral particles. Full article

(This article belongs to the Special Issue Advances in Optical Nanomanipulation)

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20 pages, 2629 KiB

Open AccessArticle

Lipidic Formulations Inspired by COVID Vaccines as Smart Coatings to Enhance Nanoparticle-Based Cancer Therapy

by Marzia Conte, Marco Carofiglio, Giada Rosso and Valentina Cauda

Nanomaterials 2023, 13(15), 2250; https://doi.org/10.3390/nano13152250 - 03 Aug 2023

Cited by 2 | Viewed by 1496

Abstract

Recent advances in nanomedicine have led to the introduction and subsequent establishment of nanoparticles in cancer treatment and diagnosis. Nonetheless, their application is still hindered by a series of challenges related to their biocompatibility and biodistribution. In this paper, we take inspiration from [...] Read more.

Recent advances in nanomedicine have led to the introduction and subsequent establishment of nanoparticles in cancer treatment and diagnosis. Nonetheless, their application is still hindered by a series of challenges related to their biocompatibility and biodistribution. In this paper, we take inspiration from the recently produced and widely spread COVID vaccines, based on the combinational use of ionizable solid lipid nanoparticles, cholesterol, PEGylated lipids, and neutral lipids able to incorporate mRNA fragments. Here, we focus on the implementation of a lipidic formulation meant to be used as a smart coating of solid-state nanoparticles. The composition of this formulation is finely tuned to ensure efficient and stable shielding of the cargo. The resulting shell is a highly customized tool that enables the possibility of further functionalizations with targeting agents, peptides, antibodies, and fluorescent moieties for future in vitro and in vivo tests and validations. Finally, as a proof of concept, zinc oxide nanoparticles doped with iron and successively coated with this lipidic formulation are tested in a pancreatic cancer cell line, BxPC-3. The results show an astonishing increase in cell viability with respect to the same uncoated nanoparticles. The preliminary results presented here pave the way towards many different therapeutic approaches based on the massive presence of highly biostable and well-tolerated nanoparticles in tumor tissues, such as sonodynamic therapy, photodynamic therapy, hyperthermia, and diagnosis by means of magnetic resonance imaging. Full article

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11 pages, 1777 KiB

Open AccessArticle

An Aqueous Process for Preparing Flexible Transparent Electrodes Using Non-Oxidized Graphene/Single-Walled Carbon Nanotube Hybrid Solution

by Min Jae Oh, Gi-Cheol Son, Minkook Kim, Junyoung Jeon, Yong Hyun Kim and Myungwoo Son

Nanomaterials 2023, 13(15), 2249; https://doi.org/10.3390/nano13152249 - 03 Aug 2023

Cited by 1 | Viewed by 791

Abstract

In this study, we prepared flexible and transparent hybrid electrodes based on an aqueous solution of non-oxidized graphene and single-walled carbon nanotubes. We used a simple halogen intercalation method to obtain high-quality graphene flakes without a redox process and prepared hybrid films using [...] Read more.

In this study, we prepared flexible and transparent hybrid electrodes based on an aqueous solution of non-oxidized graphene and single-walled carbon nanotubes. We used a simple halogen intercalation method to obtain high-quality graphene flakes without a redox process and prepared hybrid films using aqueous solutions of graphene, single-walled carbon nanotubes, and sodium dodecyl sulfate surfactant. The hybrid films showed excellent electrode properties, such as an optical transmittance of ≥90%, a sheet resistance of ~3.5 kΩ/sq., a flexibility of up to ε = 3.6% ((R) = 1.4 mm), and a high mechanical stability, even after 10³ bending cycles at ε = 2.0% ((R) = 2.5 mm). Using the hybrid electrodes, thin-film transistors (TFTs) were fabricated, which exhibited an electron mobility of ~6.7 cm² V⁻¹ s⁻¹, a current on-off ratio of ~1.04 × 10⁷, and a subthreshold voltage of ~0.122 V/decade. These electrical properties are comparable with those of TFTs fabricated using Al electrodes. This suggests the possibility of customizing flexible transparent electrodes within a carbon nanomaterial system. Full article

(This article belongs to the Special Issue Carbon Nanomaterials for Electrochemical Applications)

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13 pages, 4577 KiB

Open AccessArticle

Effect of Atmospheric Temperature on Epoxy Coating Reinforced with Carbon Nanotubes for De-Icing on Road Systems

by Seung-Jun Lee, Yu-Jin Jung, Chunhee Cho and Sung-Hwan Jang

Nanomaterials 2023, 13(15), 2248; https://doi.org/10.3390/nano13152248 - 03 Aug 2023

Viewed by 1063

Abstract

Traffic accidents caused by road icing are a serious global problem, and conventional de-icing methods like spraying chemicals have several limitations, including excessive manpower management, road damage, and environmental pollution. In this study, the carbon nanotubes reinforced de-icing coating for the road system [...] Read more.

Traffic accidents caused by road icing are a serious global problem, and conventional de-icing methods like spraying chemicals have several limitations, including excessive manpower management, road damage, and environmental pollution. In this study, the carbon nanotubes reinforced de-icing coating for the road system with a self-heating function was developed as part of the development of a new system to prevent accidents caused by road icing. The electrical characteristics of the fabricated coating were analyzed, and the carbon nanotube coating heating performance experiment was conducted to measure the temperature increments by applying a voltage to the coating at a sub-zero temperature using an environmental chamber. In addition, the coating was installed on the road pavement and the applicability was investigated through a heating test in winter. As a result of the experiment, the coating made with the higher carbon nanotube concentration presented higher heating owing to its higher electrical conductivity. In addition, the coating showed sufficient heating performance, although the maximum temperature by Joule heating decreased for the entire coating at sub-zero temperatures. Finally, field tests demonstrated the potential of electrically conductive coatings for de-icing applications. Full article

(This article belongs to the Special Issue Carbon Nanotubes and Nanosheets for Sustainable Solutions)

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14 pages, 6040 KiB

Open AccessArticle

Liquid-Phase Partial Hydrogenation of Phenylacetylene at Ambient Conditions Catalyzed by Pd-Fe-O Nanoparticles Supported on Silica

by Anastasiya A. Shesterkina, Olga A. Kirichenko, Olga P. Tkachenko, Alexander L. Kustov and Leonid M. Kustov

Nanomaterials 2023, 13(15), 2247; https://doi.org/10.3390/nano13152247 - 03 Aug 2023

Cited by 1 | Viewed by 910

Abstract

Catalysts with no hazardous or toxic components are required for the selective hydrogenation of acetylenic bonds in the synthesis of pharmaceuticals, vitamins, nutraceuticals, and fragrances. The present work demonstrates that a high selectivity to alkene can be reached over a Pd-Fe-O/SiO₂ system [...] Read more.

Catalysts with no hazardous or toxic components are required for the selective hydrogenation of acetylenic bonds in the synthesis of pharmaceuticals, vitamins, nutraceuticals, and fragrances. The present work demonstrates that a high selectivity to alkene can be reached over a Pd-Fe-O/SiO₂ system prepared by the co-impregnation of a silica support with a solution of the metal precursors (NH₄)₃[Fe(C₂O₄)₃] and [Pd(NH₃)₄]Cl₂ followed by thermal treatment in hydrogen or in air at 400 °C. A DRIFT spectroscopic study of CO adsorption revealed large shifts in the position of the Pdⁿ⁺-CO bands for this system, indicating the strong effect of Feⁿ⁺ on the Pd electronic state, resulting in a decreased rate of double C=C bond hydrogenation and an increased selectivity of alkyne hydrogenation to alkene. The prepared catalysts consisted of mono- and bimetallic nanoparticles on an SiO₂ carrier and exhibited a selectivity as high as that of the commonly used Lindlar catalyst (which contains such hazardous components as lead and barium), while the activity of the Fe-Pd-O/SiO₂ catalyst was an order of magnitude higher. The hydrogenation of a triple bond over the proposed Pd-Fe catalyst opens the way to selective hydrogenation over nontoxic catalysts with a high yield and productivity. Taking into account a simple procedure of catalyst preparation, this direction provides a rationale for the large-scale implementation of these catalysts. Full article

(This article belongs to the Special Issue Morphological Design and Synthesis of Nanoparticles)

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3 pages, 189 KiB

Open AccessEditorial

Advanced Photocatalytic Nanomaterials for Energy Conversion and Environmental Remediation

by Junying Zhang, Yong Chen and Jungang Hou

Nanomaterials 2023, 13(15), 2246; https://doi.org/10.3390/nano13152246 - 03 Aug 2023

Viewed by 654

Abstract

With the rapid development of the economy and society, the problem of energy shortage and environmental pollution is receiving more and more attention [...] Full article

(This article belongs to the Special Issue Advanced Photocatalytic Nanomaterials for Energy Conversion and Environmental Remediation)

23 pages, 9450 KiB

Open AccessArticle

Reductive Treatment of Pt Supported on Ti_0.8Sn_0.2O₂-C Composite: A Route for Modulating the Sn–Pt Interactions

by Cristina Silva, Khirdakhanim Salmanzade, Irina Borbáth, Erzsébet Dódony, Dániel Olasz, György Sáfrán, Andrei Kuncser, Erzsébet Pászti-Gere, András Tompos and Zoltán Pászti

Nanomaterials 2023, 13(15), 2245; https://doi.org/10.3390/nano13152245 - 03 Aug 2023

Viewed by 1031

Abstract

The composites of transition metal-doped titania and carbon have emerged as promising supports for Pt electrocatalysts in PEM fuel cells. In these multifunctional supports, the oxide component stabilizes the Pt particles, while the dopant provides a co-catalytic function. Among other elements, Sn is [...] Read more.

The composites of transition metal-doped titania and carbon have emerged as promising supports for Pt electrocatalysts in PEM fuel cells. In these multifunctional supports, the oxide component stabilizes the Pt particles, while the dopant provides a co-catalytic function. Among other elements, Sn is a valuable additive. Stong metal-support interaction (SMSI), i.e., the migration of a partially reduced oxide species from the support to the surface of Pt during reductive treatment is a general feature of TiO₂-supported Pt catalysts. In order to explore the influence of SMSI on the stability and performance of Pt/Ti_0.8Sn_0.2O₂-C catalysts, the structural and catalytic properties of the as prepared samples measured using XRD, TEM, XPS and electrochemical investigations were compared to those obtained from catalysts reduced in hydrogen at elevated temperatures. According to the observations, the uniform oxide coverage of the carbon backbone facilitated the formation of Pt–oxide–C triple junctions at a high density. The electrocatalytic behavior of the as prepared catalysts was determined by the atomic closeness of Sn to Pt, while even a low temperature reductive treatment resulted in Sn–Pt alloying. The segregation of tin oxide on the surface of the alloy particles, a characteristic material transport process in Sn–Pt alloys after oxygen exposure, contributed to a better stability of the reduced catalysts. Full article

(This article belongs to the Special Issue Nanomaterials Applied to Fuel Cells and Catalysts)

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12 pages, 2711 KiB

Open AccessArticle

Ce-Doped Three-Dimensional Ni/Fe LDH Composite as a Sulfur Host for Lithium–Sulfur Batteries

by Huiying Wei, Qicheng Li, Bo Jin and Hui Liu

Nanomaterials 2023, 13(15), 2244; https://doi.org/10.3390/nano13152244 - 03 Aug 2023

Cited by 2 | Viewed by 1245

Abstract

Lithium–sulfur batteries (LSBs) have become the most promising choice in the new generation of energy storage/conversion equipment due to their high theoretical capacity of 1675 mAh g⁻¹ and theoretical energy density of 2600 Wh kg⁻¹. Nevertheless, the continuous shuttling of [...] Read more.

Lithium–sulfur batteries (LSBs) have become the most promising choice in the new generation of energy storage/conversion equipment due to their high theoretical capacity of 1675 mAh g⁻¹ and theoretical energy density of 2600 Wh kg⁻¹. Nevertheless, the continuous shuttling of lithium polysulfides (LiPSs) restricts the commercial application of LSBs. The appearance of layered double hydroxides (LDH) plays a certain role in the anchoring of LiPSs, but its unsatisfactory electronic conductivity and poor active sites hinder its realization as a sulfur host for high-performance LSBs. In this paper, metal organic framework-derived and Ce ion-doped LDH (Ce-Ni/Fe LDH) with a hollow capsule configuration is designed rationally. The hollow structure of Ce-Ni/Fe LDH contains a sufficient amount of sulfur. Fe, Ni, and Ce metal ions effectively trap LiPSs; speed up the conversion of LiPSs; and firmly anchor LiPSs, thus effectively inhibiting the shuttle of LiPSs. The electrochemical testing results demonstrate that a lithium–sulfur battery with capsule-type S@Ce-Ni/Fe LDH delivers the initial discharge capacities of 1207 mAh g⁻¹ at 0.1 C and 1056 mAh g⁻¹ at 0.2 C, respectively. Even at 1 C, a lithium–sulfur battery with S@Ce-Ni/Fe LDH can also cycle 1000 times. This work provides new ideas to enhance the electrochemical properties of LSBs by constructing a hollow capsule configuration. Full article

(This article belongs to the Special Issue Recent Progress in Nanoelectrode Materials for Batteries and Supercapacitors)

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