Search

Humidity is a well-known interference factor in metal oxide (MOX) gas sensors, significantly impacting their performance in various applications such as environmental monitoring and medical diagnostics. This study investigates the effects of adsorbed water on MOX conductivity using two different materials: pure tin oxide (SnO2) and a tin–titanium–niobium oxide mixture (SnTiNb)xO2 (STN). The results reveal that (SnTiNb)xO2 sensors exhibit reduced sensitivity to humidity compared to pure tin oxide, rendering them more suitable for applications where humidity presence is critical. We aimed to shed light on a still controversial debate over the mechanisms involved in the water surface interactions for the aforementioned materials also by exploring theoretical studies in the literature. Experimental analysis involves varying temperatures (100 to 800 °C) to understand the kinetics of surface reactions. Additionally, a brief high-temperature heating method is demonstrated to effectively remove adsorbed humidity from sensor surfaces. The study employs Arrhenius-like plots for graphical interpretation, providing insights into various water adsorption/desorption phenomena. Overall, this research contributes to a deeper understanding of the role of humidity in MOX gas sensor mechanisms and offers practical insights for sensor design and optimization.

Triethylamine is a common volatile organic compound (VOC) that plays an important role in areas such as organic solvents, chemical industries, dyestuffs, and leather treatments. However, exposure to triethylamine atmosphere can pose a serious threat to human health. In this study, gas-sensing semiconductor materials of LaFeO3 nano materials with different Mo-doping ratios were synthesized by the sol–gel method. The crystal structures, micro morphologies, and surface states of the prepared samples were characterized by XRD, SEM, and XPS, respectively. The gas-sensing tests showed that the Mo doping enhanced the gas-sensing performance of LaFeO3. Especially, the 4% Mo-doped LaFeO3 exhibited the highest response towards triethylamine (TEA) gas, a value approximately 11 times greater than that of pure LaFeO3. Meantime, the 4% Mo-doped LaFeO3 sensor showed a remarkably robust linear correlation between the response and the concentration (R2 = 0.99736). In addition, the selectivity, stability, response/recovery time, and moisture-proof properties were evaluated. Finally, the gas-sensing mechanism is discussed. This study provides an idea for exploring a new type of efficient and low-cost metal-doped LaFeO3 sensor to monitor the concentration of triethylamine gas for the purpose of safeguarding human health and safety.

Copper (Cu) is the most extensively used bactericide worldwide in many agricultural production systems. However, intensive application of Cu bactericide have increased the selection pressure toward Cu-tolerant pathogens, including Xanthomonas perforans, the causal agent of tomato bacterial spot. However, alternatives for Cu bactericides are limited and have many drawbacks including plant damage and inconsistent effectiveness under field conditions. Also, potential ecological risk on nontarget organisms exposed to field runoff containing Cu is high. However, due to lack of alternatives for Cu, it is still widely used in tomato and other crops around the world in both conventional and organic production systems. In this study, a Cu-tolerant X. perforans strain GEV485, which can tolerate eight tested commercial Cu bactericides, was used in all the field trials to evaluate the efficacy of MgO nanomaterial. Four field experiments were conducted to evaluate the impact of intensive application of MgO nanomaterial on tomato bacterial spot disease severity, and one field experiment was conducted to study the impact of soil accumulation of total and bioavailable Cu, Mg, Mn, and Zn. In the first two field experiments, twice-weekly applications of 200 μg/mL MgO significantly reduced disease severity by 29-38% less in comparison to a conventional Cu bactericide Kocide 3000 and 19-30% less in comparison to the water control applied at the same frequency (p = 0.05). The disease severity on MgO twice-weekly was 12-32% less than Kocide 3000 + Mancozeb treatment. Single weekly applications of MgO had 13-19% higher disease severity than twice weekly application of MgO. In the second set of two field trials, twice-weekly applications of MgO at 1000 μg/mL significantly reduced disease severity by 32-40% in comparison to water control applied at the same frequency (p = 0.05). There was no negative yield impact in any of the trials. The third field experiment demonstrated that application of MgO did not result in significant accumulation of total and bioavailable Mg, Mn, Cu, or Zn in the root-associated soil and in soil farther away from the production bed compared to the water control. However, Cu bactericide contributed to significantly higher Mn, Cu, and Zn accumulation in the soil compared to water control (p = 0.05). This study demonstrates that MgO nanomaterial could be an alternative for Cu bactericide and have potential in reducing risks associated with development of tolerant strains and for reducing Cu load in the environment.

The science of catalysis has a direct impact on the world economy and the energy environment that positively affects the environmental ecosystem of our universe. Any catalyst, before being tested in a reaction, must undergo a specific characterization protocol to simulate its behavior under reaction conditions. In this work, these steps that must be carried out are presented, both generically and with examples, to the support and to the catalyst itself before and after the reaction. The first stage consists of knowing the textural and structural properties of the support used for the preparation of the catalysts. The specific surface area and the pore volume are fundamental properties, measured by N2 adsorption at −196 °C when preparing the catalyst, dispersing the active phase, and allowing the diffusion and reaction of the reactants and products on its surface. If knowing the structure of the catalyst is important to control its behavior against a reaction, being able to analyze the catalyst used under the reaction conditions is essential to have knowledge about what has happened inside the catalytic reactor. The most common characterization techniques in heterogeneous catalysis laboratories are those described in this work. As an application example, the catalytic conversion of CO2 to CH4 has been selected and summarized in this work. In this case, the synthesis and characterization of Cu and Ni catalysts supported on two Al2O3 with different textural properties, 92 and 310 m2/g, that allow for obtaining various metallic dispersions, between 3.3 and 25.5%, is described. The catalytic behavior of these materials is evaluated from the CO2 methanation reaction, as well as their stability from the properties they present before and after the reaction.

Abstract Due to their encouraging results, nanolubricants have been revolutionary in the field of lubrication. The degree, to which the new material may improve the tribology, energy savings, and durability, is a crucial consideration for any new additive to a conventional lubricant. The results of the earlier research on carbon, metal, metal oxide, and their composites and hybrid nanolubricants as well as their effects on tribology, are summarized in this review paper. The most popular measuring methodologies, the tribology results for lubricants with an oil base, biodegradable base, and a water base, as well as the reasons that explain these tribological advancements, are all included in this study. Finally, prospects for more study in this area are emphasized.

Polyaniline (PANI)-Fe2O3/CuO and PANI -Fe2O3/ZnO hybrid materials were developed and prepared by in situ polymerization at 0°C using ammonium persulfate as oxidant. The resulting products are investigated for their structural properties by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM), and the results confirm the formation of the hybrid architecture. In addition, the electrochemical properties of the hybrid products are investigated by cyclic voltammetry (CV) and optical properties were determined using UV-Vis Diffuse Reflectance Spectrophotometer (UV-Vis DRS). Compared to PANI/ZnO or CuO, Fe2O3/CuO or ZnO exhibit significantly improved properties. Based on the obtained results, the products thus open the way for a variety of electrical and sensors applications.

Highlights A facile and generalized design strategy of polymer precursor inks was developed for direct ink writing of metal oxide into submicron 3D architectures. The Maillard reaction between polyethyleneimine and glucose endows the 3D-printed precursors with the excellent shape fidelity during high-temperature pyrolysis. As-printed 3D periodic dielectric structure with woodpile geometry shows a significant light-matter effect in mid-infrared region.

Abstract Clean water and renewable energy sources are becoming increasingly important in the current era, as well as a future challenge, and one of the potential solutions is photocatalysis. In the current study, a simple one‐step hydrothermal technique is employed to fabricate the pure and La‐doped CuO (0%, 1%, 3%, 5%, and 7%) photocatalysts. The influence of varying La concentration on structure, morphology, and optical properties is determined by scanning electron microscope (SEM), X‐ray diffraction (XRD), ultraviolet (UV)–visible spectroscopy, and photoluminescence. SEM showed that synthesized nanostructures are irregularly spherical and transform into needle‐like nanostructures on increasing La concentration. XRD revealed the monoclinic phase with a crystallite size of 15–23 nm. The UV–visible spectrum exhibited a decrease in the band gap of La‐doped CuO needle‐like nanostructures from UV to visible light. The composition and purity of synthesized nanostructures are evaluated via the energy‐dispersive X‐ray spectrum which revealed that needle‐like nanostructures are pure without any impurity traces. The synthesized nanostructures were used as a photocatalyst against methylene blue dye to examine their photocatalytic activity. The synthesized CuO‐3La photocatalyst exhibited excellent photocatalytic performance of dye degradation and hydrogen production 95.3 μmol h−1 g−1 with more than 97% cyclic stability. Therefore, the synthesized La‐doped CuO nanostructures are potential candidates for photocatalytic water splitting and hydrogen evolution.

This study presents a quasi-online method for monitoring of dissolved volatile fatty acids (VFAs) in biogas fermentation processes with a carrier gas probe by use of thermo-cyclically operated metal oxide gas sensor arrays. Each of the two sensor arrays comprises a pure SnO2 and three different SnO2/additive-composites (additives: alumina, YSZ, NASICON) but differ by SnO2 synthesis routes, namely Flame Spray Pyrolysis (FSP) and Sol-Gel (SG) technique, respectively. This allowed comparative studies of the influence of layer morphology on VFA sensing characteristics. For sensitive determination of the dissolved VFAs besides high concentrations of biogas components like CO or CH4, first a pre-treatment routine of the fermentation sample was introduced to remove those physically dissolved gases without losing VFAs. The Conductance-over-Time-Profiles (CTPs) of eight different sensing layers were measured simultaneously at exposure to the gases extracted from the fermentation sample at different pH conditions. Almost all the investigated SnO2/additive-composites show CTP-features clearly correlating with the undissociated VFA even at concentrations below 120 ppm as referenced by GC-analysis. The lower detection limit is well below inhibitory concentration for fermentation processes. As expected, most pronounced CTPs representing actual VFAs situation were measured at pH 3, well below the pKa of the VFAs. The FSP-layers highlighted clearly better sensitivity and CTP specificity of higher quality compared to SG-layers. Among the SnO2/additives, the CTP-features of the SnO2(FSP)/NASICON and SnO2(SG)/NASICON layers showed the best specificity to acetic and propionic acid. For the first time, quasi-online analysis of VFAs using metal oxide gas sensors for early warning of VFA-development in biogas fermentation processes was demonstrated.

To produce the free-standing electrodes, a binder-free direct growth method was employed for electrode fabrication. A NiCo2O4@Ni-MOF (metal–organic framework) composite was synthesized using a one-pot hydrothermal method. Initially, a NiCo2O4 nanowire array was cultivated on Ni foam, serving as a connecting bridge to ensure robust adherence of the Ni-MOF to the substrate. The structures of NiCo2O4 nanowire arrays exhibit the capacity for numerous redox reactions. Hybridizing MOF with transition metal oxide (TMO) nanoarchitectures can significantly alleviate the small specific surface area and aggregation tendency of TMOs. The highest energy storage capacity was obtained when the ratio of nickel to terephthalic acid (TPA) was 4:1. NiCo2O4@Ni-MOF (Ni:[Formula: see text]:1) exhibited a high storage capacitance of 1700[Formula: see text]F/g. The integration of MOF with TMO nanoarchitectonics as materials for supercapacitor electrodes can enhance porous structure and facilitate diffusion during both charging and discharging processes.

A typical study has been performed for synthesizing Ag2O and ZnO nanoparticles. In our case, aloe vera extract was used as a reducing agent for synthesizing Ag2O. This green synthesis of silver oxide used silver nitrate (AgNO3) as a precursor material. On the other hand, the direct precipitation method was used for synthesizing zinc oxide nanoparticles, in which the precursor materials used were zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and potassium hydroxide (KOH). Afterward, the characterization of these synthesized nanoparticles was done by the X-ray diffraction (XRD) method. Then, the crystal size, lattice strain, stress, and energy density of synthesized ZnO and Ag2O were determined by using XRD peak profile analysis. Among the various available models for determining these microstructural parameters, we explored the Scherrer model, the linear straight-line method of the Scherrer equation, the Monshi-Scherrer model, the Sahadat-Scherrer model, the Williamson-Hall model (including the uniform deformation model, the uniform stress deformation model, the uniform deformation energy density model), the size-strain plot method, the Halder-Wagner model, etc. By employing the crystal size values from these models, the accuracy and validity of crystals were also performed. The synthesized products were also characterized by the exploration of functional groups (by FTIR) and optical band gaps (by UV technique).

Epoxy resins have been the subject of many studies as a consequence of their extensive usage in recent years. The brittleness and low resistance to propagation and crack initiation of epoxy resins are well-recognized characteristics. Therefore, in recent years, experts have concentrated on increasing epoxy resin's fracture resistance. Adding inorganic nanoparticles like titanium dioxide (TiO2) TiO2, silica (SiO2), carbon black, alumina (Al2O3), and others to the polymer matrix is one of the most investigated techniques in polymer science. Despite having a modest nanofiller content, the resulting nanocomposites may enhance their thermal, mechanical, rheological, electrical, and optical characteristics. These nanocomposites are an alternative to metal-based materials. They have great promise as multifunctional materials in a range of applications, including optoelectronic devices, semiconductor devices, civil engineering, automotive, and aerospace. To show potential future directions and market prospects for polymer nanocomposites reinforced with TiO2 nanoparticles, current results, and trends have been examined and highlighted. In addition, the current review surveys many studies that highlighted using nanoparticles as reinforcement, their different structure, the interface, and the geometry and structure of the resulting nano-materials reinforced resin.

As technologies like the Internet, artificial intelligence, and big data evolve at a rapid pace, computer architecture is transitioning from compute-intensive to memory-intensive. However, traditional von Neumann architectures encounter bottlenecks in addressing modern computational challenges. The emulation of the behaviors of a synapse at the device level by ionic/electronic devices has shown promising potential in future neural-inspired and compact artificial intelligence systems. To address these issues, this review thoroughly investigates the recent progress in metal-oxide heterostructures for neuromorphic applications. These heterostructures not only offer low power consumption and high stability but also possess optimized electrical characteristics via interface engineering. The paper first outlines various synthesis methods for metal oxides and then summarizes the neuromorphic devices using these materials and their heterostructures. More importantly, we review the emerging multifunctional applications, including neuromorphic vision, touch, and pain systems. Finally, we summarize the future prospects of neuromorphic devices with metal-oxide heterostructures and list the current challenges while offering potential solutions. This review provides insights into the design and construction of metal-oxide devices and their applications for neuromorphic systems. [ABSTRACT FROM AUTHOR]

In here, cobalt-zinc bimetallic oxides@polypyrrole (PPy) composites with core–shell structure are prepared, and the prepared Co 3 O 4 /ZnCo 2 O 4 @PPy (CZCP) has a wide absorption of 5.58 GHz, while ZnCo 2 O 4 /ZnO@PPy (ZCZP) has a strong reflection loss of −71.2 dB. [Display omitted] • By changing the ratio of Co2+ and Zn2+ of the MOF precursors, the various cobalt-zinc bimetallic oxides are fabricated. • Cobalt-zinc bimetallic oxides@polypyrrole (PPy) composites with core–shell structure are prepared through in situ polymerization method. • When the loading is 50 wt%, the EAB of Co 3 O 4 /ZnCo 2 O 4 @PPy is 5.58 GHz (12.42–18 GHz) at 1.53 mm, and the RL min of ZnCo 2 O 4 /ZnO@PPy is −71.2 dB at 13.04 GHz and 1.84 mm. Composite materials that combine magnetic and dielectric losses offer a potential solution to enhance impedance match and significantly improve microwave absorption. In this study, Co 3 O 4 /ZnCo 2 O 4 and ZnCo 2 O 4 /ZnO with varying metal oxide compositions are successfully synthesized, which are achieved by modifying the ratios of Co2+ and Zn2+ ions in the CoZn bimetallic metal–organic framework (MOF) precursor, followed by a high-temperature oxidative calcination process. Subsequently, a layer of polypyrrole (PPy) is coated onto the composite surfaces, resulting in the formation of core–shell structures known as Co 3 O 4 /ZnCo 2 O 4 @PPy (CZCP) and ZnCo 2 O 4 /ZnO@PPy (ZCZP) composites. The proposed method allows for rapid adjustments to the metal oxide composition within the inner shell, enabling the creation of composites with varying degrees of magnetic losses. The inclusion of PPy in the outer shell serves to enhance the bonding strength of the entire composite structure while contributing to conductive and dielectric losses. In specific experimental conditions, when the loading is set at 50 wt%, the CZCP composite exhibits an effective absorption bandwidth (EAB) of 5.58 GHz (12.42 GHz-18 GHz) at a thickness of 1.53 mm. Meanwhile, the ZCZP composite demonstrates an impressive minimum reflection loss (RL min) of −71.2 dB at 13.04 GHz, with a thickness of 1.84 mm. This study offers a synthesis strategy for designing absorbent composites that possess light weight and excellent absorptive properties, thereby contributing to the advancement of electromagnetic wave absorbing materials. [ABSTRACT FROM AUTHOR]

Nanoparticles (NPs) find widespread applications in detectors, catalysis, optoelectronics, and medical devices, owing to their high surface-to-volume ratio and zero-dimensional confinement. However, addressing environmental concerns is crucial during the creation of novel nanostructured materials. Herein, ZnO NPs of different sizes were prepared via the pulsed laser ablation in liquid (PLAL) method at energies of 70, 90, and 130 mJ. The morphology and structural properties of the synthesized NPs were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry, and transmission electron microscopy. zeta-sizer and zeta-potential were used to ensure the physical stability of NPs. UV-Vis spectrophotometry measurement showed a blue shift in the band gaps with an increase in the pulsed laser energy leading to a decrease in the size of the NPs. Fourier-transform infrared spectroscopy technique confirmed the formation of ZnO NPs. [ABSTRACT FROM AUTHOR]

In this study, the performance of dye-sensitized photovoltaic cells and electron charge recombination properties of p-n heterojunction diodes were enhanced by incorporating TiO2 into pristine ZnO nanoparticles. The ZnO nanomaterials were prepared using a green mediated technique, and the TiO2 deposition over ZnO nanoparticles was achieved through the sol–gel method. Structural analysis confirmed that the ZnO nanoparticles exhibited a hexagonal wurtzite structure, while the TiO2 nanoparticles displayed a hexagonal structure. Morphological analysis revealed that the ZnO particles had a spherical shape, whereas TiO2 particles formed clusters. The nanomaterials were further investigated to assess their functional, linear optical, and magnetic properties. For the p-n heterojunction analysis, n-type pure ZnO and ZnO/TiO2 nanomaterials were coated onto a p-type silicon substrate. The results demonstrated that the incorporation of TiO2 nanomaterials improved the coercivity and magnetization of the device. Moreover, the power conversion efficiency of the dye-sensitized solar cells significantly increased for the ZnO/TiO2 photoanode, indicating a reduced charge recombination. The TiO2 incorporated ZnO exhibited a higher efficiency (7.85%) compared to pristine ZnO (7.47%). [ABSTRACT FROM AUTHOR]

Green synthesis of metal oxide nanoparticles has gained prominence in recent years, resulting from the absence of toxic chemicals, low energy requirement, and eco-friendliness. This paper reports the green synthesis of zinc oxide nanoparticles (ZnO-NPs) using plant extract as a reducing agent. The ZnO-NPs were synthesized using Corchorus olitorius leaf extract and zinc acetate dihydrate, Zn (CH3COO)2.2H2O as precursor. The synthesized ZnO-NPs were characterized by the application of UV–Vis spectroscopy, Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX) and Fourier Transform Infrared Spectroscopy (FTIR). UV-vis indicated the reduction of zinc acetate dihydrate into ZnO-NPs by the leave extract. XRD and TEM revealed that the average size of the synthesized ZnO-NPs was 22 nm. The XRD pattern showed the hexagonal wurtzite crystalline nature of the synthesized ZnO-NPs. The elemental composition obtained from EDX showed that the synthesized ZnO-NPs are primarily composed of three elements: Zn (75.20 %), O (20.48.7%), and C (4.32). Examination of stretching and bonding in the ZnO-NPs using FT-IR revealed the presence of Zn-O bonding at 430.37–403.93 cm-1. [ABSTRACT FROM AUTHOR]

The hybrid electrode material of transition metal oxide/carbon has good potential for the remarkable performance of supercapacitors. Here pine sawdust derived carbons were prepared with highly dispersed Mn, Mn–Fe or Mn–Ni oxides and hierarchical porous structure by CO2 gasification. Effects of the CO2 gasification conditions (including the gasification temperature, gasification reaction time and the metal loading amount) were investigated on the surface metal species, pore structures and morphology of the hybrid materials. The as-prepared hybrid materials show the total metal content less than 6.5 wt% but display good electrochemical performance, along with the specific capacitance up to 369.5–750.6 F g−1 at 0.5 A g−1 in the three-electrode system. Those doped with Mn–Fe or Mn–Ni binary metal composite can be a better candidate than that doped with the unary metal. The assembled asymmetric supercapacitor presents a high energy density of 13.9 Wh kg−1 at 375.9 W kg−1 in a potential window of 0–1.5 V. Besides, excellent cycling performance can be achieved with the capacitance retention rate of 92.8% after 5000 charge-discharge cycles at 5 A g−1. The synergism of the introduced metal oxides and carbon skeleton with the hierarchical porous structure enables the hybrid materials to provide the desirable specific capacitance, outstanding rate capability and cycling performance. [ABSTRACT FROM AUTHOR]

This study investigated the structural, morphological, and photoluminescent properties of ZnO nanopowders doped with Mo and V, which were synthesized using pulsed laser reactive technology. The nanoparticles' structure, shape, and size were determined using electron microscopy and X-ray diffractometry. The photoluminescence properties of the Mo- and V-doped ZnO nanopowders in different gas environments were studied, revealing that changes in the gas environment led to significant alterations in the intensity and deformation of the photoluminescence spectra. All samples exhibited strong emission bands in the UV range and a broad, non-elemental emission band in the visible region ranging from 410 to 600 nm. Decomposing the photoluminescence spectra into elementary bands revealed peaks at 430 and 520 nm. Chromaticity diagrams of the photoluminescence light emitted by the nanopowders were obtained, and it was found that the color coordinates varied depending on the gas environment, which could be useful in gas sensors. [ABSTRACT FROM AUTHOR]

LiCoO2 (LCO) powders were protonated and their catalytic activity on the thermal decomposition of ammonium perchlorate (AP) was tested using differential scanning calorimetry and thermogravimetric analysis. Powders were characterized using SEM, XRD, and BET surface area analysis to quantify the morphology and structure. The thermal analysis showed that protonated powders enhanced the catalytic activity in AP decomposition over commercial and unmodified LiCoO2, Fe2O3 and Co3O4 catalyst powders. The activation energies were investigated using the model-free Kissinger method, and the possible mechanisms governing the catalytic activity are discussed. The activation energies of AP thermal decomposition were decreased significantly by the use of these protonated catalysts. For neat AP, commercial LCO, and protonated LCO the activation energy for LTD and HTD were: 104 ± 5 kJ/mol and 143 ± 4 kJ/mol, 89 ± 4 kJ/mol and 92 ± 14 kJ/mol, and 76 ± 6 kJ/mol and 98 ± 7 kJ/mol respectively. We believe the hydrogen and vacancies in the protonated lattice act as reaction sites for the decomposition of AP. [ABSTRACT FROM AUTHOR]

The Tauc plot is a method originally developed to derive the optical gap of amorphous semiconductors such as amorphous germanium or silicon. By measuring the absorption coefficient α(hν) and plotting (αhv)12$(\alpha {hv})^{\frac{1}{2}}$ versus photon energy hν, a value for the optical gap (Tauc gap) is determined. In this way non‐direct optical transitions between approximately parabolic bands can be examined. In the last decades, a modification of this method for (poly‐) crystalline semiconductors has become popular to study direct and indirect interband transitions. For this purpose, (ahν)n (n = 12$\frac{1}{2}$, 2) is plotted against hν to determine a value of the electronic bandgap. Due to the ease of performing UV–vis measurements, this method has nowadays become a standard to analyze various (poly‐) crystalline solids, regardless of their different electronic structure. Although this leads partially to widely varying values of the respective bandgap of nominally identical materials, there is still no study that critically questions which peculiarities in the electronic structure prevent a use of the Tauc plot for (poly‐) crystalline solids and to which material classes this applies. This study aims to close this gap by discussing the Tauc plot and its limiting factors for exemplary (poly‐) crystalline solids with different electronic structures. [ABSTRACT FROM AUTHOR]

With the increasing attention to health, especially the impact of COVID-19 in recent years, the research and application of antimicrobial materials have gradually become a research hotspot. Adding antimicrobial agents to various materials is the most common, simple, and effective processing method. The activity of antimicrobial agent has a great influence on the effect and use of antimicrobial material. The photocatalytic metal oxides have the advantages of high antimicrobial performance and long-term activity. In this paper, the antimicrobial mechanisms, types, and applications of photocatalytic metal oxides were described, focusing on the research status and existing problems of photocatalytic metal oxides and doped metal oxides commonly used as inorganic antimicrobials. The future application prospect and research directions of photocatalytic metal oxide antimicrobials were proposed. [ABSTRACT FROM AUTHOR]

In this study, hybrid polymer nanocomposites were produced by combining epoxy (EP) with varying amounts of zirconia (ZrO 2) and yttria (Y2O 3) nanoparticles (NPs), reinforced with multi-walled carbon nanotube (MWCNT) and glass fiber (GF). The objective of this study is to develop and examine the performance of EP nanocomposites through hybridization; for this purpose, hardness and impact tests were conducted in accordance with American Society for Testing and Materials (ASTM) standards. Different sets were produced to investigate the effect of used fillers, including EP/ZrO2, EP/Y2O3, EP/MWCNT, EP/GF, EP/ZrO2/Y2O3, EP/MWCNT/ZrO2/Y2O3, and EP/MWCNT/GF/ZrO2/Y2O3. All findings were compared with the net EP sample. The results showed that the EP nanocomposite samples with low NPs content exhibit much higher mechanical performance than net EP. Furthermore, the additions of MWCNT and GF separately at 0.1 and 0.06 wt.% have increased the impact strength, respectively, to 165.2% and 338.8%, compared with pure EP. As a result, the presence of MWCNTs and GF in the EP-based nanocomposite matrix could make the product both stronger and tougher. [ABSTRACT FROM AUTHOR]

In this research, a nano-inorganic composite of CuO/NiO is prepared by co-precipitation method as an efficient recyclable nanocatalyst for the regioselective synthesis of 1,4-disubstituted-1,2,3-triazoles in water. The catalyst was characterized by several techniques such as the field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), x-ray fluorescence, inductively coupled plasma atomic emission spectroscopy (ICP-OES), and brunauer-emmett-teller (BET) surface area analysis. The regioselective synthesis of 1,4-disubstituted-1,2,3-triazoles was carried out from reaction of various benzyl halides or alkyl halides with phenyl acetylene and sodium azide in water under reflux condition in high yields. The CuO/NiO nanocatalyst can be simply recovered and reused 6 runs without a significant slight in activity. [ABSTRACT FROM AUTHOR]

Cement-based materials with thermoelectric effect can realize the conversion of waste heat in building environment, which is of great significance in energy conversion and utilization, and has become a research hotspot in recent years. In this study, three kinds of metal oxides were added into the phase change modified expanded graphite cement-based composites to investigate the impact of metal oxide content on the thermoelectric characteristics of cement composites. The findings shown that the thermoelectric properties of cement-based materials can be enhanced by the addition of metal oxides. The power factor increased to 3.15 μW·m−1·K−2, 3.60 μW·m−1·K−2, and 2.53 μW·m−1·K−2 after mixing ZnO, CuO, and TiO2. This is because the incorporation of metal oxides introduced a large number of interfaces into the cement, increased carrier scattering, strengthened the Seebeck coefficient of cement, and improved the power factor. This work presented a novel strategy to improving the thermoelectric properties of cement-based materials. [ABSTRACT FROM AUTHOR]

Sodium-modified litho-vanadium glasses containing non-magnetic Aluminium ions of composition 50Li2CO3 - (30-X) Na2 CO3-20V2O5 -xAl2O3 (30 = x = 5) (LNVA) glasses were prepared by melt quenching technique. The density of the glass samples was measured and found to increase with the Aluminium content of the glass matrix. The measured values of refractive index and polaron radius of the glass network show opposite behaviour with an increase of Aluminium content. Through band gap energy and refractive index, Oxide ion polarizability and electronic polarizability were determined by using the Lorentz-Lorenz equation. The value of Oxide ion polarizability and electronic polarizability is found to be decreased with decreasing band gap energy and increasing refractive index. The value of optical basicity was measured using electronic polarizability and is found to be decreased with decreasing inter-nuclear distance. The band gap energy values of the glass network were found to decrease from 3.241 to 2.134 eV. The metallisation criterion of the glass material was calculated and found to decrease with Aluminium content. [ABSTRACT FROM AUTHOR]

We synthesized zinc oxide nanoparticles (ZnO NPs) by meticulously controlling both temperature and reaction times, allowing us to fine-tune their crystalline properties, morphology, and particle dimensions. This analysis confirmed the existence of a mixture of rod and sphere shapes (ZnO-I), including rod-shaped NPs with an average size of 14.8 nm × 5.2 nm and spherical NPs with an average diameter of 5.27 nm. We subsequently incorporated these synthesized ZnO NPs into organic light-emitting diode (OLED) devices for red, green, and blue colors, utilizing them as the electron injection layer through a solution-based process. The green OLED device using ZnO-I exhibited a promising current efficiency of 4.02 cd/A and an external quantum efficiency of 1.47%. [ABSTRACT FROM AUTHOR]

Separation of thorium, uranium, and rare earth elements (REEs) requires selective materials with high capacity, good thermal, chemical and radiation resistance. For this aim, Zr, Si and Ti oxide nanoparticles (NPs) have been prepared using metal alkoxide precursors via hydrothermal method. Polyacrylonitrile (PAN) was used as a supporting material to obtain nanocomposite (NC) beads for the potential use in industrial scale applications. The surface characteristics and morphological properties of nano metal oxide powders and composites were determined. Metal uptake and separation studies of thorium and REEs were carried out from sulfuric acid leach solution of Beylikova ore. [ABSTRACT FROM AUTHOR]

Herein, the structure, thermal stability, optical, magnetic characteristics, and adsorption performance towards methylene blue (MB) of Sn 1- x Zn 2 x Cr 2 O 5 nanocomposites (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1), prepared by the hydrothermal method, were investigated. The crystal structures, elemental chemical compositions and surface morphology were conducted using XRD, TEM, EDX, and SEM techniques. The structural parameters significantly depend on the elemental composition. For example, a tetragonal SnO 2 phase was formed at x = 0, and 0.2, while a spinel-structured ZnCr 2 O 4 was formed at x ≥ 0.4 beside the orthorhombic CrO 3 phases. The mass magnetic susceptibility and magnetization of the Sn 1- x Zn 2 x Cr 2 O 5 nanocomposites displayed a weak room temperature ferromagnetism behavior. The maximum surface area (100.89 m2/g), evaluated via the Brunauer-Emmett-Teller method, was achieved for Sn 0.6 Zn 0.8 Cr 2 O 5 nanocomposite. The optical band gap and Urbach energy show opposite trends and are slightly influenced by Zn content. Moreover, the impact of the Zn2+ ratio on the structure, optical, thermal stability, and magnetic characteristics was correlated. The adsorption performance of the Sn 1- x Zn 2 x Cr 2 O 5 nanocomposite (0 ≤ x ≤ 0.6) revealed an excellent removal efficiency (max ∼87.64%) towards MB dye with apparent rate kinetic constant of 44.9 × 10–2 min–1. [ABSTRACT FROM AUTHOR]

The incineration of agricultural waste (agro-waste) as a fuel or solid fuel results in landfilled ash that in most cases results in an environmental problem in its disposal. We highlighted an excellent overview for the utilization of different types of agricultural waste, such as rice husk and straw, sugarcane bagasse, bamboo leaves, banana peel, onion peel, and other agricultural waste employed for the fabrication of low-cost, environmentally friendly, and high potential range nanomaterials. In this review, we summarized the synthesis process and applications of metal oxide nanomaterials such as ZnO and SiO2, which are promising value-added material for various purposes, using agricultural waste as raw material. We have also discussed different applications, toxic effects as well as management of agricultural waste by the "3R" strategy of the agricultural waste management system. We conclude this review by suggesting future applications of agricultural waste as well as providing protective measures against global pollution. [ABSTRACT FROM AUTHOR]

Welding fumes contain harmful metals and gas by-products associated with development of lung dysfunction, asthma, bronchitis, and lung cancer. Two prominent welding fume particulate metal components are nanosized iron (Fe) and manganese (Mn) which might induce oxidative stress and inflammation resulting in pulmonary injury. Welding fume toxicity may be dependent upon metal nanoparticle (NP) components. To examine toxicity of welding fume NP components, a system was constructed for controlled and continuous NP generation from commercial welding and customized electrodes with varying proportions of Fe and Mn. Aerosols generated consisted of nanosized particles and were compositionally consistent with each electrode. Human alveolar lung A459 epithelial cells were exposed to freshly generated metal NP mixtures at a target concentration of 100 µg/m3 for 6 hr and then harvested for assessment of cytotoxicity, generation of reactive oxygen species (ROS), and alterations in the expression of genes and proteins involved in metal regulation, inflammatory responses, and oxidative stress. Aerosol exposures decreased cell viability and induced increased ROS production. Assessment of gene expression demonstrated variable up-regulation in cellular mechanisms related to metal transport and storage, inflammation, and oxidative stress based upon aerosol composition. Specifically, interleukin-8 (IL-8) demonstrated the most robust changes in both transcriptional and protein levels after exposure. Interleukin-8 has been determined to serve as a primary cytokine mediating inflammatory responses induced by welding fume exposures in alveolar epithelial cells. Overall, this study demonstrated variations in cellular responses to metal NP mixtures suggesting compositional variations in NP content within welding fumes may influence inhalation toxicity. [ABSTRACT FROM AUTHOR]

Herein, we report a simple non-enzymatic electrochemical sensor for the detection of serotonin (5-HT) in blood serum using ZnO oxide nanoparticles-copper metal-organic framework (MOF) composite on 3D porous nickel foam, namely, ZnO-Cu MOF/NF. The x-ray diffraction analysis reveals the crystalline nature of synthesized Cu MOF and Wurtzite structure of ZnO nanoparticles, whereas SEM characterization confirms the high surface area of the composite nanostructures. Differential pulse voltammetry analysis under optimal conditions yields a wide linear detection range of 1 ng ml−1 to 1 mg ml−1 to 5-HT concentrations and a LOD (signal to noise ratio = 3.3) of 0.49 ng ml−1, which is well below the lowest physiological concentration of 5-HT. The sensitivity of the fabricated sensor is found to be 0.0606 mA ng−1 ml−1.cm2, and it exhibited remarkable selectivity towards serotonin in the presence of various interferants, including dopamine and AA, which coexist in the real biological matrix. Further, successful determination of 5-HT is achieved in the simulated blood serum sample with a good recovery percentage from ∼102.5% to ∼99.25%. The synergistic combination of the excellent electrocatalytic properties and surface area of the constituent nanomaterials proves the overall efficacy of this novel platform and shows immense potential to be used in developing versatile electrochemical sensors. [ABSTRACT FROM AUTHOR]

In the last several decades, metal oxide thin films have attracted significant attention for the development of various existing and emerging technological applications, including pH sensors. The mandate for consistent and precise pH sensing techniques has been increasing across various fields, including environmental monitoring, biotechnology, food and agricultural industries, and medical diagnostics. Metal oxide thin films grown using physical vapor deposition (PVD) with precise control over film thickness, composition, and morphology are beneficial for pH sensing applications such as enhancing pH sensitivity and stability, quicker response, repeatability, and compatibility with miniaturization. Various PVD techniques, including sputtering, evaporation, and ion beam deposition, used to fabricate thin films for tailoring materials' properties for the advanced design and development of high-performing pH sensors, have been explored worldwide by many research groups. In addition, various thin film materials have also been investigated, including metal oxides, nitrides, and nanostructured films, to make very robust pH sensing electrodes with higher pH sensing performance. The development of novel materials and structures has enabled higher sensitivity, improved selectivity, and enhanced durability in harsh pH environments. The last decade has witnessed significant advancements in PVD thin films for pH sensing applications. The combination of precise film deposition techniques, novel materials, and surface functionalization strategies has led to improved pH sensing performance, making PVD thin films a promising choice for future pH sensing technologies. [ABSTRACT FROM AUTHOR]

The ternary composite MgO@ZnO@BC was synthesized and characterized for the adsorption of Cu2+, Pb2+ heavy metal ions from wastewater. The results show that the addition of the MgO@ZnO@BC composite results in higher adsorption properties for Cu2+ and Pb2+, with a molar ratio of 5% 0.1 g, and maximum adsorption capacity (50.63 mg/g for Cu2+ and 61.46 mg/g for Pb2+). The Langmuir adsorption isotherm of the adsorption complex and the kinetics of adsorption are secondary kinetics. The adsorption of Cu2+ and Pb2+ was mainly chemisorption, accompanied by physical adsorption. This adsorption method fully conforms to the concepts of clean production and efficient waste utilization, providing a reference for the removal of heavy metal ions from wastewater and waste recycling using ternary composite materials. [ABSTRACT FROM AUTHOR]

Electrochemical reduction processes of oxides in molten salt have been proposed as the carbon-free technologies in order to achieve carbon neutrality. The anodic behavior of La1−xSrxFeO3−δ as an O2 evolution anode in LiCl–KCl at 723 K was investigated. The results suggested that at 723 K, the electrical conductivity of La1−xSrxFeO3−δ tended to increase with the Sr doping. The anodic reactions of the La1−xSrxFeO3−δ electrodes were characterized by electrochemical measurements in LiCl–KCl + Li2O at 723 K. Based on the cyclic voltammograms of the La0.7Sr0.3FeO3−δ electrode, O2 evolution has proceeded between 2.7 and 3.6 V. The potential of the La0.7Sr0.3FeO3−δ electrode during galvanostatic electrolysis has conducted at 39 mA cm−2 for 15 h has remained stable at 2.8 V, indicating that the stable evolution of O2 gas was monitored. The corrosion rate was estimated to have the low value of 8.6 × 10−4 g cm−2 h−1. Electrode surface data obtained after electrolysis indicated that the La0.7Sr0.3FeO3−δ electrode exhibited excellent chemical and physical stability in LiCl–KCl at 723 K. This indicates that the La0.7Sr0.3FeO3−δ electrode is promising candidate material as inert anodes for oxide decomposition. As an application of the La0.7Sr0.3FeO3−δ electrode, the electrolytic reduction of CO2 was also successfully achieved. [ABSTRACT FROM AUTHOR]