2024

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24 pages, 2443 KiB

Open AccessReview

An Updated Overview of Silica Aerogel-Based Nanomaterials

by Adelina-Gabriela Niculescu, Dana-Ionela Tudorache, Maria Bocioagă, Dan Eduard Mihaiescu, Tony Hadibarata and Alexandru Mihai Grumezescu

Nanomaterials 2024, 14(5), 469; https://doi.org/10.3390/nano14050469 - 04 Mar 2024

Cited by 1 | Viewed by 1392

Abstract

Silica aerogels have gained much interest due to their unique properties, such as being the lightest solid material, having small pore sizes, high porosity, and ultralow thermal conductivity. Also, the advancements in synthesis methods have enabled the creation of silica aerogel-based composites in [...] Read more.

Silica aerogels have gained much interest due to their unique properties, such as being the lightest solid material, having small pore sizes, high porosity, and ultralow thermal conductivity. Also, the advancements in synthesis methods have enabled the creation of silica aerogel-based composites in combination with different materials, for example, polymers, metals, and carbon-based structures. These new silica-based materials combine the properties of silica with the other materials to create a new and reinforced architecture with significantly valuable uses in different fields. Therefore, the importance of silica aerogels has been emphasized by presenting their properties, synthesis process, composites, and numerous applications, offering an updated background for further research in this interdisciplinary domain. Full article

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2023

Jump to: 2024, 2022

18 pages, 12477 KiB

Open AccessArticle

Microwave-Assisted Silanization of Magnetite Nanoparticles Pre-Synthesized by a 3D Microfluidic Platform

by Adelina-Gabriela Niculescu, Alina Moroșan, Alexandra Cătălina Bîrcă, Oana Gherasim, Ovidiu Cristian Oprea, Bogdan Ștefan Vasile, Bogdan Purcăreanu, Dan Eduard Mihaiescu, Marius Rădulescu and Alexandru Mihai Grumezescu

Nanomaterials 2023, 13(20), 2795; https://doi.org/10.3390/nano13202795 - 20 Oct 2023

Viewed by 1139

Abstract

Magnetite nanoparticles (Fe₃O₄ NPs) are among the most investigated nanomaterials, being recognized for their biocompatibility, versatility, and strong magnetic properties. Given that their applicability depends on their dimensions, crystal morphology, and surface chemistry, Fe₃O₄ NPs must be [...] Read more.

Magnetite nanoparticles (Fe₃O₄ NPs) are among the most investigated nanomaterials, being recognized for their biocompatibility, versatility, and strong magnetic properties. Given that their applicability depends on their dimensions, crystal morphology, and surface chemistry, Fe₃O₄ NPs must be synthesized in a controlled, simple, and reproducible manner. Since conventional methods often lack tight control over reaction parameters and produce materials with unreliable characteristics, increased scientific interest has been directed to microfluidic techniques. In this context, the present paper describes the development of an innovative 3D microfluidic platform suitable for synthesizing uniform Fe₃O₄ NPs with fine-tuned properties. On-chip co-precipitation was performed, followed by microwave-assisted silanization. The obtained nanoparticles were characterized from the compositional and microstructural perspectives by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Moreover, supplementary physicochemical investigations, such as Fourier Transform Infrared Spectroscopy (FT-IR), Kaiser Test, Ultraviolet-Visible (UV-Vis) Spectrophotometry, Dynamic Light Scattering (DLS), and Thermogravimetry and Differential Scanning Calorimetry (TG-DSC) analyses, demonstrated the successful surface modification. Considering the positive results, the presented synthesis and functionalization method represents a fast, reliable, and effective alternative for producing tailored magnetic nanoparticles. Full article

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2022

Jump to: 2024, 2023

17 pages, 4297 KiB

Open AccessArticle

Threshold Switching in Forming-Free Anodic Memristors Grown on Hf–Nb Combinatorial Thin-Film Alloys

by Ivana Zrinski, Janez Zavašnik, Jiri Duchoslav, Achim Walter Hassel and Andrei Ionut Mardare

Nanomaterials 2022, 12(22), 3944; https://doi.org/10.3390/nano12223944 - 09 Nov 2022

Cited by 4 | Viewed by 1271

Abstract

The development of novel materials with coexisting volatile threshold and non-volatile memristive switching is crucial for neuromorphic applications. Hence, the aim of this work was to investigate the memristive properties of oxides in a Hf–Nb thin-film combinatorial system deposited by sputtering on Si [...] Read more.

The development of novel materials with coexisting volatile threshold and non-volatile memristive switching is crucial for neuromorphic applications. Hence, the aim of this work was to investigate the memristive properties of oxides in a Hf–Nb thin-film combinatorial system deposited by sputtering on Si substrates. The active layer was grown anodically on each Hf–Nb alloy from the library, whereas Pt electrodes were deposited as the top electrodes. The devices grown on Hf-45 at.% Nb alloys showed improved memristive performances reaching resistive state ratios up to a few orders of magnitude and achieving multi-level switching behavior while consuming low power in comparison with memristors grown on pure metals. The coexistence of threshold and resistive switching is dependent upon the current compliance regime applied during memristive studies. Such behaviors were explained by the structure of the mixed oxides investigated by TEM and XPS. The mixed oxides, with HfO₂ crystallites embedded in quasi amorphous and stoichiometrically non-uniform Nb oxide regions, were found to be favorable for the formation of conductive filaments as a necessary step toward memristive behavior. Finally, metal–insulator–metal structures grown on the respective alloys can be considered as relevant candidates for the future fabrication of anodic high-density in-memory computing systems for neuromorphic applications. Full article

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14 pages, 10550 KiB

Open AccessEditor’s ChoiceArticle

Microfluidic Synthesis of -NH₂- and -COOH-Functionalized Magnetite Nanoparticles

by Cristina Chircov, Alexandra Cătălina Bîrcă, Bogdan Stefan Vasile, Ovidiu-Cristian Oprea, Keng-Shiang Huang and Alexandru Mihai Grumezescu

Nanomaterials 2022, 12(18), 3160; https://doi.org/10.3390/nano12183160 - 12 Sep 2022

Cited by 9 | Viewed by 1879

Abstract

Microfluidics has emerged as a promising alternative for the synthesis of nanoparticles, which ensures precise control over the synthesis parameters, high uniformity, reproducibility, and ease of integration. Therefore, the present study investigated a one-step synthesis and functionalization of magnetite nanoparticles (MNPs) using sulfanilic [...] Read more.

Microfluidics has emerged as a promising alternative for the synthesis of nanoparticles, which ensures precise control over the synthesis parameters, high uniformity, reproducibility, and ease of integration. Therefore, the present study investigated a one-step synthesis and functionalization of magnetite nanoparticles (MNPs) using sulfanilic acid (SA) and 4-sulfobenzoic acid (SBA). The flows of both the precursor and precipitating/functionalization solutions were varied in order to ensure the optimal parameters. The obtained nanoparticles were characterized through dynamic light scattering (DLS) and zeta potential, X-ray diffraction (XRD), selected area electron diffraction (SAED), transmission electron microscopy (TEM) and high-resolution TEM (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry and differential scanning calorimetry (TG-DSC), and vibrating sample magnetometry (VSM). The results demonstrated the successful synthesis of magnetite as the unique mineralogical phase, as well as the functionalization of the nanoparticles. Furthermore, the possibility to control the crystallinity, size, shape, and functionalization degree by varying the synthesis parameters was further confirmed. In this manner, this study validated the potential of the microfluidic platform to develop functionalized MNPs, which are suitable for biomedical and pharmaceutical applications. Full article

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9 pages, 1774 KiB

Open AccessCommunication

Uncovering the Role of Surface-Attached Ag Nanoparticles in Photodegradation Improvement of Rhodamine B by ZnO-Ag Nanorods

by Svetlana Em, Mussa Yedigenov, Laura Khamkhash, Shanazar Atabaev, Anara Molkenova, Stavros G. Poulopoulos and Timur Sh. Atabaev

Nanomaterials 2022, 12(16), 2882; https://doi.org/10.3390/nano12162882 - 22 Aug 2022

Cited by 6 | Viewed by 1524

Abstract

ZnO nanorods decorated with metal nanoparticles have sparked considerable interest in recent years thanks to their suitability for a wide range of applications, such as photocatalysis, photovoltaics, antibacterial activity, and sensing devices. In this study, we prepared and investigated the improved solar-light-assisted photocatalytic [...] Read more.

ZnO nanorods decorated with metal nanoparticles have sparked considerable interest in recent years thanks to their suitability for a wide range of applications, such as photocatalysis, photovoltaics, antibacterial activity, and sensing devices. In this study, we prepared and investigated the improved solar-light-assisted photocatalytic activity of ZnO nanorods (NRs) decorated with Ag nanoparticles (NPs) using a conventional rhodamine B (RB) dye as a model water pollutant. We showed that the presence of Ag NPs on the surface of ZnO NRs significantly increases the degradation rate of RB dye (~0.2432 min⁻¹) when compared to bare ZnO NRs (~0.0431 min⁻¹). The improved photocatalytic activity of ZnO-Ag was further experimentally tested using radical scavengers. The obtained results reveal that ˙OH and ˙O₂⁻ radicals are main active species involved in the RB dye photodegradation by ZnO-Ag NRs. It was concluded that efficient charge separation plays a major role in photocatalytic activity improvement. Full article

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15 pages, 4015 KiB

Open AccessArticle

Remarkable Recycling Process of ZnO Quantum Dots for Photodegradation of Reactive Yellow Dye and Solar Photocatalytic Treatment Process of Industrial Wastewater

by Walied Mohamed, Hala Abd El-Gawad, Hala Handal, Hoda Galal, Hanan Mousa, Badr El-Sayed, Saleh Mekkey, Ibrahem Ibrahem and Ammar Labib

Nanomaterials 2022, 12(15), 2642; https://doi.org/10.3390/nano12152642 - 31 Jul 2022

Cited by 4 | Viewed by 1651

Abstract

The mineralization of five industrial sunlight-exposed wastewater samples was investigated, and the recycling process of ZnO quantum dots (ZQDs) for five reusable times was estimated under the approved Egyptian Environmental Law COD (Chemical Oxygen Demand), which has to be less than 1000 ppm. [...] Read more.

The mineralization of five industrial sunlight-exposed wastewater samples was investigated, and the recycling process of ZnO quantum dots (ZQDs) for five reusable times was estimated under the approved Egyptian Environmental Law COD (Chemical Oxygen Demand), which has to be less than 1000 ppm. An improved sol-gel process at a low calcination temperature that ranged between 350 and 450 °C was employed to synthesize ZnO quantum dots (ZQDs). The purity, high crystallinity, and structure of the prepared catalysts were determined by TEM and XRD analysis. The energy bandgap, the crystal size values, and the surface area for Z1 and Z2 were determined based on the TEMs, DRSs, and EBTs, which were equal to 6.9 nm, 3.49 eV, and 160.95 m²/g for Z1 and 8.3 nm, 3.44 eV, and 122.15 m²/g for Z2. The investigation of the prepared samples was carried out by studying the photocatalytic activity and photoluminescence, and it was found that the degradation rate of reactive yellow dye as an industrial pollutant of the Z1 sample was significantly higher than other samples, by 20%. The data collection has shown that photocatalytic efficiency decreases with an increase in the crystallite size of ZQDs. Full article

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11 pages, 2790 KiB

Open AccessArticle

High-Density and Monodisperse Electrochemical Gold Nanoparticle Synthesis Utilizing the Properties of Boron-Doped Diamond Electrodes

by Kenshin Takemura, Wataru Iwasaki, Nobutomo Morita and Shinya Ohmagari

Nanomaterials 2022, 12(10), 1741; https://doi.org/10.3390/nano12101741 - 19 May 2022

Cited by 6 | Viewed by 1609

Abstract

Owing to its simplicity and sensitivity, electrochemical analysis is of high significance in the detection of pollutants and highly toxic substances in the environment. In electrochemical analysis, the sensitivity of the sensor and reliability of the obtained signal are especially dependent on the [...] Read more.

Owing to its simplicity and sensitivity, electrochemical analysis is of high significance in the detection of pollutants and highly toxic substances in the environment. In electrochemical analysis, the sensitivity of the sensor and reliability of the obtained signal are especially dependent on the electrode characteristics. Electrodes with a high density of nanomaterials, which exhibit excellent activity, are useful as sensor substrates for pollutant detection. However, the effective placement of high-density nanomaterials requires a high degree of control over the particle size, particle shape, and distance between the particles on the substrate. In this study, we exploited the properties of boron-doped diamond (BDD) electrodes, which have a wide potential window, and succeeded in coating a highly dense layer of gold nanoparticles (AuNPs) at high potential. The AuNP-modified BDD (AuNP-BDD) electrodes comprising less than 100 nm AuNPs at a density of 125 particles/µm were electrochemically synthesized over a short period of 30–60 s. The AuNP-BDD electrodes were applied for detecting arsenic, which is one of the most abundant elements, and exhibited a limit of detection of 0.473 ppb in solution. Full article

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13 pages, 3186 KiB

Open AccessArticle

Application of Response Surface Methodology for Optimization of Nanosized Zinc Oxide Synthesis Conditions by Electrospinning Technique

by Aizhan Rakhmanova, Sandugash Kalybekkyzy, Baktiyar Soltabayev, Aiman Bissenbay, Nazym Kassenova, Zhumabay Bakenov and Almagul Mentbayeva

Nanomaterials 2022, 12(10), 1733; https://doi.org/10.3390/nano12101733 - 18 May 2022

Cited by 5 | Viewed by 2012

Abstract

Zinc oxide (ZnO) is a well-known semiconductor material due to its excellent electrical, mechanical, and unique optical properties. ZnO nanoparticles are widely used for the industrial-scale manufacture of microelectronic and optoelectronic devices, including metal oxide semiconductor (MOS) gas sensors, light-emitting diodes, transistors, capacitors, [...] Read more.

Zinc oxide (ZnO) is a well-known semiconductor material due to its excellent electrical, mechanical, and unique optical properties. ZnO nanoparticles are widely used for the industrial-scale manufacture of microelectronic and optoelectronic devices, including metal oxide semiconductor (MOS) gas sensors, light-emitting diodes, transistors, capacitors, and solar cells. This study proposes optimization of synthesis parameters of nanosized ZnO by the electrospinning technique. A Box–Behnken design (BB) has been applied using response surface methodology (RSM) to optimize the selected electrospinning and sintering conditions. The effects of the applied voltage, tip-to-collector distance, and annealing temperature on the size of ZnO particles were successfully investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images confirm the formation of polyvinylpyrrolidone-zinc acetate (PVP-ZnAc) fibers and nanostructured ZnO after annealing. X-ray diffraction (XRD) patterns indicate a pure phase of the hexagonal structure of ZnO with high crystallinity. Minimal-sized ZnO nanoparticles were synthesized at a constant applied potential of 16 kV, with a distance between collector and nozzle of 12 cm, flow rate of 1 mL/h, and calcination temperature of 600 °C. The results suggest that nanosized ZnO with precise control of size and morphology can be fabricated by varying electrospinning conditions, precursor solution concentration, and sintering temperature. Full article

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21 pages, 3047 KiB

Open AccessReview

Overview of the Influence of Silver, Gold, and Titanium Nanoparticles on the Physical Properties of PEDOT:PSS-Coated Cotton Fabrics

by Fahad Alhashmi Alamer and Rawan F. Beyari

Nanomaterials 2022, 12(9), 1609; https://doi.org/10.3390/nano12091609 - 09 May 2022

Cited by 18 | Viewed by 2713

Abstract

Metallic nanoparticles have been of interest to scientists, and they are now widely used in biomedical and engineering applications. The importance, categorization, and characterization of silver nanoparticles, gold nanoparticles, and titanium nanoparticles have been discussed. Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) is the most practical and [...] Read more.

Metallic nanoparticles have been of interest to scientists, and they are now widely used in biomedical and engineering applications. The importance, categorization, and characterization of silver nanoparticles, gold nanoparticles, and titanium nanoparticles have been discussed. Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) is the most practical and reliable conductive polymer used in the manufacturing of conductive textiles. The effects of metallic nanoparticles on the performance of PEDOT:PSS thin films are discussed. The results indicated that the properties of PEDOT:PSS significantly depended on the synthesis technique, doping, post-treatment, and composite material. Further, electronic textiles known as smart textiles have recently gained popularity, and they offer a wide range of applications. This review provides an overview of the effects of nanoparticles on the physical properties of PEDOT:PSS-coated cotton fabrics. Full article

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21 pages, 6390 KiB

Open AccessArticle

Effect of Co-Doping on Cu/CaO Catalysts for Selective Furfural Hydrogenation into Furfuryl Alcohol

by Munsuree Kalong, Sakhon Ratchahat, Pongtanawat Khemthong, Suttichai Assabumrungrat and Atthapon Srifa

Nanomaterials 2022, 12(9), 1578; https://doi.org/10.3390/nano12091578 - 06 May 2022

Cited by 7 | Viewed by 2070

Abstract

Cu/CaO catalysts with fine-tuned Co-doping for excellent catalytic performance of furfural (FAL) hydrogenation to furfuryl alcohol (FOL) were synthesized by a facile wetness impregnation method. The optimal Co_1.40Cu₁/CaO catalyst, with a Co to Cu mole ratio of 1.40:1, exhibited [...] Read more.

Cu/CaO catalysts with fine-tuned Co-doping for excellent catalytic performance of furfural (FAL) hydrogenation to furfuryl alcohol (FOL) were synthesized by a facile wetness impregnation method. The optimal Co_1.40Cu₁/CaO catalyst, with a Co to Cu mole ratio of 1.40:1, exhibited a 100% FAL conversion with a FOL yield of 98.9% at 100 °C and 20 bar H₂ pressure after 4 h. As gained from catalyst characterizations, Co addition could facilitate the reducibility of the CoCu system. Metallic Cu, Co-Cu alloys, and oxide species with CaO, acting as the major active components for the reaction, were formed after reduction at 500 °C. Additionally, this combination of Co and Cu elements could result in an improvement of catalyst textures when compared with the bare CaO. Smaller catalyst particles were formed after the addition of Co into Cu species. It was found that the addition of Co to Cu on the CaO support could fine-tune the appropriate acidic and basic sites to boost the FOL yield and selectivity with suppression of undesired products. These observations could confirm that the high efficiency and selectivity are mainly attributed to the synergistic effect between the catalytically active Co-Cu species and the CaO basic sites. Additionally, the FAL conversion and FOL yield insignificantly changed throughout the third consecutive run, confirming a high stability of the developed Co_1.40Cu₁/CaO catalyst. Full article

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20 pages, 5758 KiB

Open AccessArticle

The Photocatalytic Performance of Nd₂O₃ Doped CuO Nanoparticles with Enhanced Methylene Blue Degradation: Synthesis, Characterization and Comparative Study

by Fatma El-Sayed, Mai S. A. Hussien, Mervat I. Mohammed, Vanga Ganesh, Thekrayat H. AlAbdulaal, Heba Y. Zahran, Ibrahim S. Yahia, Hosam H. Hegazy, Mohamed Sh. Abdel-wahab, Mohd. Shkir, Santiyagu Valarasu and Medhat A. Ibrahim

Nanomaterials 2022, 12(7), 1060; https://doi.org/10.3390/nano12071060 - 24 Mar 2022

Cited by 7 | Viewed by 2348

Abstract

The growth of the textile industry results in a massive accumulation of dyes on water. This enormous rise in pigments is the primary source of water pollution, affecting the aquatic lives and our ecosystem balance. This study aims to notify the fabrication of [...] Read more.

The growth of the textile industry results in a massive accumulation of dyes on water. This enormous rise in pigments is the primary source of water pollution, affecting the aquatic lives and our ecosystem balance. This study aims to notify the fabrication of neodymium incorporated copper oxide (Nd₂O₃ doped CuO) nanoparticles by combustion method for effective degradation of dye, methylene blue (MB). X-ray diffraction (XRD), Field emission Scanning electron microscopy (FESEM), Zeta potential have been applied for characterization. Photocatalyst validity has been evaluated for methylene blue degradation (MB). Test conditions such as time of contact, H₂O₂, pH, and photo-Fenton have been modified to identify optimal degradation conditions. Noticeably, 7.5% Nd₂O₃ doped CuO nanoparticle demonstrated the highest photocatalytic efficiency, up to 90.8% in 80 min, with a 0.0227 min⁻¹ degradation rate. However, the photocatalytic efficiency at pH 10 becomes 99% with a rate constant of 0.082 min⁻¹. Cyclic experiments showed the Nd₂O₃ doped CuO nanoparticle’s stability over repeated use. Scavenge hydroxyl radical species responsible for degradation using 7.5% Nd₂O₃ doped CuO nanoparticles have been investigated under visible irradiation. Full article

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