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CuO, MnO and CuMnO nanomaterials have been prepared using the chemical precipitation method. The structure of the nanomaterials has been confirmed using XRD analysis. Metal oxide vibrations have been identified and assigned to the vibrational band. The morphology of the prepared nanomaterials has been investigated in the SEM images. The optical band of the materials has been calculated using Tauc’s relation from the UV-Vis spectrum. The photocatalytic nature of the prepared nanomaterials has been studied against Congo red and Malachite green dyes. [ABSTRACT FROM AUTHOR]

This study investigates the concentration-dependent speciation and stability of Keggin-type [PVWVI12O40]3–(PW12) and Wells-Dawson type [α-PV2WVI18O62]6–(P2W18) polyoxotungstates across the pH range from two to eight and buffer systems including acetic acid-sodium acetate, citric acid-sodium citrate, sodium phosphate, Tris-HCl and HEPES. Utilizing 31P Nuclear Magnetic Resonance spectroscopy for detailed analysis, we quantified the stability and hydrolysis patterns of PW12 and P2W18 in various buffer solutions at concentrations of 3, and 15 mM, and compared with previously published data for 10 mM solutions. Our research shows that higher concentrations of PW12 and P2W18 in solutions improve their stability in neutral to moderately alkaline environments (pH seven and above), making them less prone to hydrolysis. This pronounced effect underscores the crucial role of concentration in optimizing the behavior of polyoxometalates under varying pH levels, revealing a strong link between concentration and stability across various buffers and highlighting how ionic strength, buffer composition, and pH crucially interact to influence POM stability. Research on how ionic strength affects the speciation of 3 mM solutions shows that the stability of P2W18 decreases as the pH approaches neutrality and as ionic strength increases, indicating heightened hydrolysis and reduced stability. For the inherently less stable PW12, the findings indicate a shift in hydrolysis pathways—different concentrations of the hydrolysis products, a change likely driven by the increased ionic strength. These findings emphatically underscore the critical importance of meticulously selecting the right buffer and concentration to fully unlock the potential of polyoxometalates such as PW12 and P2W18. Strategic choices are essential for leveraging these compounds as pivotal elements in groundbreaking applications, poised to revolutionize scientific and technological landscapes.

CuO, MnO and CuMnO nanomaterials have been prepared using chemical precipitation method. Structure of the nanomaterials have been confirmed using XRD analysis. Metal oxide vibration have been identified and assigned to the vibrational band. Morophology of the prepared nanomaterials have been investigated in the SEM images. Optical band of the materials have been calculated using Tauc’s relation from the UV-Vis spectrum. Photocatalytic nature of the prepared nanomaterials has been studied against Congo red and Malachite green dyes.

The commencement of the cold-chain from the milk production points in smallholder and unorganized dairying in developing nations is still an unmet need. In the present study, an attempt was made to develop nanofluid based phase change materials (n-PCMs), using A12O3, CuO and TiO2 nanoparticles (at 0.00%, 0,50% and 1.00%) for efficient storage of thermal energy and its subsequent utilization in rapid chilling of milk. Thermal conductivity of the n-PCMs was enhanced up to 29.49% as compared to the base fluid (water) and exhibited the supercooling reduction by 53.74%. Slight reductions in the specific and latent heats were observed (maximum at 1.00% level of nanoparticles) in the range of 0.10-0.25 and 0.4-0.8 k#kg, respectively. The n-PCMs capsuled inside a spherical module exhibited energy storage and milk chilling rate augmentations up to 31.97% and 39.11%, respectively. Temperature mapping of n-PCMs along the central vertical points (viz., upper, middle and lower) inside the spherical capsule exhibited the distinct trends during the pre and post phase-transition regimes, which were primarily driven by the buoyancy and natural convections. The study demonstrated the feasibility of developing the energy efficient passive chillers for rapid chilling of milk under the field conditions. [ABSTRACT FROM AUTHOR]

Taktic, an Amitraz-based insecticide, is commonly used in sub-Saharan Africa to treat cattle for ticks. Due to misuse in rural dipping pools, some ticks are showing resistance to Taktic. This work presents a low-cost e-nose with commercial sensors to monitor Taktic levels in dipping pool water. The device shows distinctly different measurements for the odours of air, distilled water, farm water, and four levels of Taktic insecticide in farm water. A naive Bayes algorithm with a Gaussian distribution is trained on the data and a validation set achieves a 96.5% accuracy. This work also compares two sol-gel ZnO nanoparticle solutions with an off-the-shelf ZnO nanoparticle ink for use as active material in chemiresistive gas sensors to be employed in an e-nose array. The ZnO solutions are screen-printed onto gold electrodes, auto-sintered with a built in heater, and used with UV illumination to operate as low-power, room temperature gas sensors. All of the screen-printed ZnO sensors show distinct changes in resistance when exposed to Taktic vapours under room temperature and humidity conditions. The custom room temperature ZnO gas sensors fabricated via facile and low-cost processes are suitable for future integration in a point-of-need microsystem for the detection of Taktic in water. [ABSTRACT FROM AUTHOR]

In this work, the structural, vibrational, morphological, and colloidal properties of commercial 15.1 nm TiO2 nanoparticles (NPs) and nanowires (NWs, 5.6 thickness, 74.6 nm length) were studied with the purpose of determining their ecotoxicological properties. This was achieved by evaluating acute ecotoxicity experiments carried out in the environmental bioindicator Daphnia magna, where their 24-h lethal concentration (LC50) and morphological changes were evaluated using a TiO2 suspension (pH = 7) with point of zero charge at 6.5 for TiO2 NPs (hydrodynamic diameter of 130 nm) and 5.3 for TiO2 NWs (hydrodynamic diameter of 118 nm). Their LC50 values were 157 and 166 mg L−1 for TiO2 NWs and TiO2 NPs, respectively. The reproduction rate of D. magna after fifteen days of exposure to TiO2 nanomorphologies was delayed (0 pups for TiO2 NWs and 45 neonates for TiO2 NPs) in comparison with the negative control (104 pups). From the morphological experiments, we may conclude that the harmful effects of TiO2 NWs are more severe than those of 100% anatase TiO2 NPs, likely associated with brookite (36.5 wt. %) and protonic trititanate (63.5 wt. %) presented in TiO2 NWs according to Rietveld quantitative phase analysis. Specifically, significant change in the heart morphological parameter was observed. In addition, the structural and morphological properties of TiO2 nanomorphologies were investigated using X-ray diffraction and electron microscopy techniques to confirm the physicochemical properties after the ecotoxicological experiments. The results reveal that no alteration in the chemical structure, size (16.5 nm for TiO2 NPs and 6.6 thickness and 79.2 nm length for NWs), and composition occurred. Hence, both TiO2 samples can be stored and reused for future environmental purposes, e.g., water nanoremediation. [ABSTRACT FROM AUTHOR]

We propose a cost-effective computational approach for predicting the phase boundary of oxide solid solutions, i.e., melting point, by identifying the point where the free energies of the solid and liquid phases are equivalent. To evaluate the melting point, we computed the temperature-dependent free energies of both phases using the thermodynamic integration (TI) method. This was combined with the reverse-scaling technique, employing the Einstein model for the solid and the scaled Uhlenbeck–Ford model for the liquid as the reference systems. The change in free energy between the real and reference states in the present TI method was calculated as the ensemble average of the configurations sampled from molecular dynamics (MD) simulations using neural network potentials (NNPs) trained on first-principles density functional theory (DFT) data. Initially, we benchmarked copper (Cu) as a typical metal. Tungsten (W) and magnesium oxide (MgO) were then tested as typical high melting-point metals and oxides, respectively, achieving good agreement with both ab initio MD (AIMD) results and experimental data. We then applied our established approach to a BaO–CaO oxide solid solution, observing that the computed phase boundary aligns well with Calphad predictions from previous studies. The integration of NNPs into phase boundary prediction is essential for reducing computational costs while ensuring accuracy, compared with AIMD-based approaches. • Neural network-based potentials are proposed for cost-effective and high-accuracy prediction tools of phase diagrams. • The above concepts are validated for solid–liquid phase boundaries of metal-oxides with high melting points. • Accuracies of phase boundaries calculated by molecular dynamics using neural network potentials are comparable to those of the Calphad method. [ABSTRACT FROM AUTHOR]

Heterojunction-based gas sensors are very attractive as they substantially improve the sensing characteristics due to the effective potential barrier present at the interface. Taking the advantages of two excellent semiconducting gas sensing materials i.e., SnO 2 and ZnO, herein, we have constructed ZnO/SnO 2 heterojunction by the combination of vacuum evaporation and r.f. sputtering or atomic layer deposition techniques. The ZnO/SnO 2 heterostructure with optimized thickness of ZnO (∼10 nm) shows a 6-fold enhancement in sensing response compared to bare SnO 2 films against CO gas. The sensing responses of 81 and 85 % have been obtained for ZnO/SnO 2 heterostructures with ZnO deposited by sputtering and atomic layer deposition (ALD) methods, respectively, against 91 ppm of CO gas with an estimated limit of detection of 1.67 and 0.37 ppm. The ALD ZnO/SnO 2 sample displays an extremely fast response time of 5 s. The heterostructure sensors are also highly selective towards CO gas in the presence of other interfering toxic agents. The enhanced sensing characteristics of ZnO/SnO 2 are assigned to the formation of n-n heterojunction as depicted by X-ray photoelectron spectroscopic band alignment study and the strong CO adsorption on ZnO surface as derived from density functional theory calculations. [ABSTRACT FROM AUTHOR]

Aliovalent-doped metal oxide nanocrystals exhibiting localized surface plasmons (LSPRs) are applied in systems that require reflection/scattering/absorption in infrared and optical transparency in visible. Indium tin oxide (ITO) is currently leading the field, but indium resources are known to be very restricted. Antimony-doped tin oxide (ATO) is a cheap candidate to substitute the ITO, but it exhibits less advantageous electronic properties and limited control of the LSPRs. To date, LSPR tuning in ATO NCs has been achieved electrochemically and by aliovalent doping, with a significant decrease in doping efficiency with an increasing doping level. Here, we synthesize plasmonic ATO nanocrystals (NCs) via a solvothermal route and demonstrate ligand exchange to tune the LSPR energies. Attachment of ligands acting as Lewis acids and bases results in LSPR peak shifts with a doping efficiency overcoming those by aliovalent doping. Thus, this strategy is of potential interest for plasmon implementations, which are of potential interest for infrared upconversion, smart glazing, heat absorbers, or thermal barriers. [ABSTRACT FROM AUTHOR]

In the domain of gas sensing, metal oxide nanostructures have been demonstrated to have very attractive properties due to their large surface-over-volume ratio, combined with the possibility to use multiple materials and multi-functional properties. Here, we review the basic physical principles underlying the transducer function of metal oxide nanostructures, from single nanostructures to nanostructure networks. These principles have been adapted to describe the response of more complex nanostructures, such as heterostructures, combining two different metal oxide materials, or a metal with a metal oxide, in order to further enhance the sensitivity and selectivity of such devices. We finally present the activation of nanostructures by light exposure as a promising alternative to the standard method based on high temperature activation, which is earning increasing consensus in the perspective of low-power Internet of Things applications.

The growth in industrialization ultimately enhances the toxic discharges of wastewater containing hazardous dyes from various industrial units as a consequence severe ecological and public health issue exhibit a major challenge to conventional system to decontaminate water. Depending upon experimental constrains various physicochemical and biological treatment process have been made possible to remove pollutant of interest according to their functional abilities. In spite of all the treatment techniques, Adsorption process is considered one of the most excellent option due to the cost-effectiveness, ease of operation, high removal efficiency and regeneration of adsorbents. Over the decades, metal oxides and their composites-based absorbents showed tremendous efficiency in wastewater decontamination by dyes. The ample surface-active sites, tunable surface chemistry, ease to synthesize and functionalization, high accessible surface area, economic viability, and good recyclability make the metal oxide-based nanomaterials potential adsorbents for fast and effective removal of a wide range of heavy metal and metalloid ions. The presence of toxic dye molecules in water system poses a serious threat to aquatic ecosystem. This paper comprehensively reviews the source of contamination, possible health hazards, and adsorption technique by metal oxides to eliminate dyes from wastewater. Also, an environmentally friendly and self-sustainable treatment method should be explored to address this problem for emerging contaminants.

Taktic, an Amitraz-based insecticide, is commonly used in sub-Saharan Africa to treat cattle for ticks. Due to misuse in rural dipping pools, some ticks are showing resistance to Taktic. This work presents a low-cost e-nose with commercial sensors to monitor Taktic levels in dipping pool water. The device shows distinctly different measurements for the odours of air, distilled water, farm water, and four levels of Taktic insecticide in farm water. A naive Bayes algorithm with a Gaussian distribution is trained on the data and a validation set achieves a 96.5% accuracy. This work also compares two sol-gel ZnO nanoparticle solutions with an off-the-shelf ZnO nanoparticle ink for use as active material in chemiresistive gas sensors to be employed in an e-nose array. The ZnO solutions are screen-printed onto gold electrodes, auto-sintered with a built in heater, and used with UV illumination to operate as low-power, room temperature gas sensors. All of the screen-printed ZnO sensors show distinct changes in resistance when exposed to Taktic vapours under room temperature and humidity conditions. The custom room temperature ZnO gas sensors fabricated via facile and low-cost processes are suitable for future integration in a point-of-need microsystem for the detection of Taktic in water.

We present a multifunctional structural coloration strategy for solar cell glass covers based on all-dielectric nanoscatterer arrays. Titanium dioxide (TiO2) nanostructures are designed to efficiently scatter in the visible and absorb in the UV region, making them suitable candidates as UV absorptive color coatings. Results from finite difference time domain (FDTD) simulations on a square lattice of TiO2 nanocylinders show that a rich palette in the reflected colors can be obtained by varying the period of the lattice. The reflected colors are narrow-banded, with a typical FWHM ~11–17 nm, leading to a minimal penalty on the amount of transmitted light. This narrow band reflectance is attributed to the interaction of Mie resonances between individual scatterers with their neighbors in the lattice. The color appearance, with viewing angles of ~45°, is maintained for incidence angles up to ~70°. With TiO2 being transparent for a major part of silicon solar cells spectral response (400–1100 nm), a loss of ~4.5–9.2% in the short-circuit current has been estimated in the specified wavelength range, primarily due to the loss of photons in the reflected light. Furthermore, due to the inherent UV-absorption properties of TiO2, the proposed color-cover designs reduce the transmittance of UV radiation (320–400 nm) by up to ~63.70%, potentially preventing the degradation of the encapsulation materials and thus increasing the lifetime expectancy of a solar panel. [ABSTRACT FROM AUTHOR]

In this work, the structural, vibrational, morphological, and colloidal properties of commercial 15.1 nm TiO2 nanoparticles (NPs) and nanowires (NWs, 5.6 thickness, 74.6 nm length) were studied with the purpose of determining their ecotoxicological properties. This was achieved by evaluating acute ecotoxicity experiments carried out in the environmental bioindicator Daphnia magna, where their 24-h lethal concentration (LC50) and morphological changes were evaluated using a TiO2 suspension (pH = 7) with point of zero charge at 6.5 for TiO2 NPs (hydrodynamic diameter of 130 nm) and 5.3 for TiO2 NWs (hydrodynamic diameter of 118 nm). Their LC50 values were 157 and 166 mg L−1 for TiO2 NWs and TiO2 NPs, respectively. The reproduction rate of D. magna after fifteen days of exposure to TiO2 nanomorphologies was delayed (0 pups for TiO2 NWs and 45 neonates for TiO2 NPs) in comparison with the negative control (104 pups). From the morphological experiments, we may conclude that the harmful effects of TiO2 NWs are more severe than those of 100% anatase TiO2 NPs, likely associated with brookite (36.5 wt. %) and protonic trititanate (63.5 wt. %) presented in TiO2 NWs according to Rietveld quantitative phase analysis. Specifically, significant change in the heart morphological parameter was observed. In addition, the structural and morphological properties of TiO2 nanomorphologies were investigated using X-ray diffraction and electron microscopy techniques to confirm the physicochemical properties after the ecotoxicological experiments. The results reveal that no alteration in the chemical structure, size (16.5 nm for TiO2 NPs and 6.6 thickness and 79.2 nm length for NWs), and composition occurred. Hence, both TiO2 samples can be stored and reused for future environmental purposes, e.g., water nanoremediation.

Aliovalent-doped metal oxide nanocrystals exhibiting localized surface plasmons (LSPRs) are applied in systems that require reflection/scattering/absorption in infrared and optical transparency in visible. Indium tin oxide (ITO) is currently leading the field, but indium resources are known to be very restricted. Antimony-doped tin oxide (ATO) is a cheap candidate to substitute the ITO, but it exhibits less advantageous electronic properties and limited control of the LSPRs. To date, LSPR tuning in ATO NCs has been achieved electrochemically and by aliovalent doping, with a significant decrease in doping efficiency with an increasing doping level. Here, we synthesize plasmonic ATO nanocrystals (NCs) via a solvothermal route and demonstrate ligand exchange to tune the LSPR energies. Attachment of ligands acting as Lewis acids and bases results in LSPR peak shifts with a doping efficiency overcoming those by aliovalent doping. Thus, this strategy is of potential interest for plasmon implementations, which are of potential interest for infrared upconversion, smart glazing, heat absorbers, or thermal barriers.

Metal‐oxides (MeOx), for example electrical conducting sub‐stoichiometric Molybdenum‐Oxide (MoOx) can be used to create dark layers to cover otherwise reflective lines. While the optical properties are well developed and understood, this work focuses on the investigation of chemical stability, relevant for process integration. For this we analyze and compare different alloys and summarize the thin film properties for different applications. [ABSTRACT FROM AUTHOR]

Unique classes of active‐site motifs are needed for improved electrocatalysis. Herein, the activity of a new catalyst motif is engineered and isolated for the oxygen evolution reaction (OER) created by nickel–iron transition metal electrocatalysts confined within a layered zirconium phosphate matrix. It is found that with optimal intercalation, confined NiFe catalysts have an order of magnitude improved mass activity compared to more conventional surface‐adsorbed systems in 0.1 m KOH. Interestingly, the confined environments within the layered structure also stabilize Fe‐rich compositions (90%) with exceptional mass activity compared to known Fe‐rich OER catalysts. Through controls and by grafting inert molecules to the outer surface, it is evidenced that the intercalated Ni/Fe species stay within the interlayer during catalysis and serve as the active site. After determining a possible structure (wycherproofite), density functional theory is shown to correlate with the observed experimental compositional trends. It is further demonstrated that the improved activity of this motif is correlated to the Fe and water content/composition within the confined space. This work highlights the catalytic enhancement possibilities available through zirconium phosphate and isolates the activity from the intercalated species versus surface/edge ones, thus opening new avenues to develop and understand catalysts within unique nanoscale chemical environments. [ABSTRACT FROM AUTHOR]

We present a multifunctional structural coloration strategy for solar cell glass covers based on all-dielectric nanoscatterer arrays. Titanium dioxide (TiO2) nanostructures are designed to efficiently scatter in the visible and absorb in the UV region, making them suitable candidates as UV absorptive color coatings. Results from finite difference time domain (FDTD) simulations on a square lattice of TiO2 nanocylinders show that a rich palette in the reflected colors can be obtained by varying the period of the lattice. The reflected colors are narrow-banded, with a typical FWHM ~11–17 nm, leading to a minimal penalty on the amount of transmitted light. This narrow band reflectance is attributed to the interaction of Mie resonances between individual scatterers with their neighbors in the lattice. The color appearance, with viewing angles of ~45°, is maintained for incidence angles up to ~70°. With TiO2 being transparent for a major part of silicon solar cells spectral response (400–1100 nm), a loss of ~4.5–9.2% in the short-circuit current has been estimated in the specified wavelength range, primarily due to the loss of photons in the reflected light. Furthermore, due to the inherent UV-absorption properties of TiO2, the proposed color-cover designs reduce the transmittance of UV radiation (320–400 nm) by up to ~63.70%, potentially preventing the degradation of the encapsulation materials and thus increasing the lifetime expectancy of a solar panel.

Tin oxide (SnO 2) and zinc oxide (ZnO) coupled metal-oxide nanocomposites or SnO 2 –ZnO were prepared using a sol-gel method. The stretching mode frequencies and crystal structures were examined by using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), respectively. The microscopic analyses by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed a flower-like morphology of the nanocomposites. The analysis of surface chemical and electronic states was conducted by X-ray photoelectron spectroscopy (XPS). The band gap energies as confirmed from the ultraviolet–visible spectroscopy (UV–Vis) data were found to be larger than those of the bulk band gaps due to the increase between energy levels associated with smaller particle sizes. The UV (380 nm) and orange (595) photoluminescence (PL) emissions observed from the SnO 2 :ZnO nanocomposites were attributed to a combinatorial contribution from radiative transitions in SnO 2 and ZnO components. The proposed mechanisms of these emissions are discussed. [ABSTRACT FROM AUTHOR]

Importance of multifunctional finishing of textiles is increasing day by day due to greater consumer demand. Cross-linker is one of the commonly used finishes agent to impart functionality in textiles. In this research work the performance of the formaldehyde free carboxylic acid based eco-friendly cross-linkers; citric acid (CA) and maleic acid (MA) was enhanced by incorporating three different types of metal oxides nanoparticle (ZnO, MgO and CaO). Two different fixation methods of pad-dry-cure with and without UV irradiation were used. ZnO along with CA and MA was found to be most effective in increasing crease recovery performance of the cotton fabric followed by MgO while CaO was found to be ineffective. Fabric tear strength was also improved by the incorporation of these nanoparticles. Additionally, incorporation of these nanoparticles exhibited improvement in the fabric handle and antimicrobial properties. [ABSTRACT FROM AUTHOR]

Abstract The dyes are one of major pollutants discharged to water bodies without any premeditation. Their undesirable detection in aqueous bodies has created a menace as they tend to disturb the complete aquatic ecosystem by directly hindering the photosynthetic process of aquatic flora. Thus pre and post discharge remediation of these dyes are of immense significance. In the present study, novel OG/La 2 O 3 /ZrO 2 nanocomposite having high photocatalytic ability was prepared by co-precipitation method. Visible photocatalytic ability of the nanocomposite was employed for the degradation of fast green dye as a target pollutant. The OG/La 2 O 3 /ZrO 2 nanocomposite was well characterized using various techniques as FTIR, XRD, SEM, TEM and XPS etc. The nanocomposite also exhibited adsorption capability due to the presence of oxidized graphite (OG) sheets those provided high surface area for the fast green molecules to get adsorb onto them. High degradation efficiency (89%) was obtained within 90 min of visible light irradiation. Effect of pH, photocatalyst amount and light intensity was also studied. Superoxide and hydroxyl radicals were found to be the major reacting species as confirmed by the scavenging studies. Furthermore, OG/La 2 O 3 /ZrO 2 nanocomposite exhibited high reusability interpreting the nanocomposite as a proficient photocatalyst with active utilization for treating industrial waste water. Graphical abstract Unlabelled Image Highlights • OG/La 2 O 3 /ZrO 2 nanocomposite was fabricated by simple co-precipitation method. • OG sheets provided high surface area for attachment of La 2 O 3 and ZrO 2 particles. • Superoxide and hydroxyl radicals were the major reacting species. • Catalytic reduction of fast green dye by OG/La 2 O 3 /ZrO 2 nanocomposite [ABSTRACT FROM AUTHOR]

Quasi-two-dimensional (2D) β-Ga2O3 is a rediscovered metal-oxide semiconductor with an ultra-wide bandgap of 4.6-4.9 eV. It has been reported to be a promising material for next-generation power and radio frequency electronics. Field effect transistors (FETs) that can switch at high voltage are key components in power and radio frequency devices, and reliable Ohmic contacts are essential for high FET performance. However, obtaining low contact resistance on β-Ga2O3 FETs is difficult since reactions between β-Ga2O3 and metal contacts are not fully understood. Herein, we experimentally demonstrate the importance of reactions at the metal/β-Ga2O3 interface and the corresponding effects of these reactions on FET performance. When Ti is employed as the metal contact, annealing of β-Ga2O3 FETs in argon can effectively transform Schottky contacts into Ohmic contacts and permit a large drain current density of ~ 3.1 mA/μm. The contact resistance (Rcontact) between the Ti electrodes and β-Ga2O3 decreased from ~ 430 to ~ 0.387 Ω·mm after annealing. X-ray photoelectron spectroscopy (XPS) confirmed the formation of oxygen vacancies at the Ti/β-Ga2O3 interface after annealing, which is believed to cause the improved FET performance. The results of this study pave the way for greater application of β-Ga2O3 in electronics. [ABSTRACT FROM AUTHOR]

Silver thin film mirrors are attractive candidates for use as specular back reflectors to enhance broadband light absorption via strong optical interference in ultrathin film semiconductor photoabsorbers. However, deposition of metal-oxide absorbers often requires exposure to high temperature in an oxygen atmosphere, conditions that cause thermal etching and degrade the specular reflectance of silver films. Here, we overcome this challenge and demonstrate that epitaxial growth of silver mitigates thermal etching under the high-temperature oxygen-containing environments that cause polycrystalline films to degrade. The degree of thermal etching resistance is related to the epitaxial film structure, where high-quality films completely prevent thermal etching, allowing for direct deposition of metal-oxide thin film photoabsorbers at elevated temperatures without any degradation of the optical properties of the silver layer. As a proof of concept for device applications, a metal-oxide photoanode for photoelectrochemical water splitting is fabricated by directly growing epitaxial SnO 2 and Ti-doped α-Fe 2 O 3 (hematite) thin films onto stabilized silver reflectors by pulsed laser deposition. The photoanode displays enhanced broadband light absorption due to strong interference effects enabled by the highly reflective silver film and demonstrates stable operation in a photoelectrochemical cell under conditions of water photo-oxidation in alkaline electrolyte.

The individual components being ample, inexpensive and non-toxic material, TiO 2 -V 2 O 5 has drawn more attention compared to other metal oxides. The cost-effective, non-toxic TiO 2 -V 2 O 5 nanocomposites with various molar ratios of Ti and V have been synthesized through wet chemical method. Microstructure studies have been performed using X-ray diffraction (XRD), FESEM, HRTTEM and other spectroscopic (XPS, FTIR) techniques. The synthesized TiO 2 -V 2 O 5 nanocomposite with molar ratio 10:20 exhibits 3D, mesoporous interlinked tube-like structure with excellent electrochemical properties by delivering highest specific capacitance of 310 F g −1 at 2 mV s −1 scan rate compared to individual TiO 2 and V 2 O 5 material. Increase in vanadium ratio plays a leading role to the chemical properties. The synergistic effects between TiO 2 and V 2 O 5 have also been observed in this work. Due to the excellent electrochemical as well as other acceptable performance, the porous interconnected tube like nanocomposite can be used for energy storage application mainly for pseudocapacitor electrode material. [ABSTRACT FROM AUTHOR]

Atomic layer deposition (ALD) is a vapor-phase technique capable of producing inorganic thin films with precise control over the thickness of the film. The ALD method offers high precision in the design of advanced 3D nanostructures. In this article, silica and alumina thin films have been grown over fibers of cellulose by the ALD process. The morphology and the chemical composition of the fabricated thin films are characterized, as well as their thermal durability through elevated temperatures. Moreover, XPS is used to confirm the phases of the alumina nanofilms and to further understand the deposition process on the cellulose microfibers. [ABSTRACT FROM AUTHOR]

• WO x -TiO 2 -Al 2 O 3 exhibits a catalytic capacity comparable to HZSM-5. • The Ti3+ in W-O-Ti bond can act as Lewis acid sites to bind to C-O bonds. • The increase in Lewis acid favors the deoxygenation reaction. • The coupling effect of WO x and Al 2 O 3 promotes the alkylation reactions of aromatics. Lignin catalytic pyrolysis for sustainable aromatic production is a promising approach for reducing the overwhelming dependence on fossil resources while mitigating CO 2 emissions. The key to achieving the efficient catalytic pyrolysis of lignin lies in the rational design of advanced catalysts with excellent deoxygenation capacity. In this study, we develop a novel mixed metal oxide (WO x -TiO 2 -Al 2 O 3) as efficient solid Lewis acid catalysts for the catalytic pyrolysis of lignin. We demonstrate that WO x -TiO 2 -Al 2 O 3 exhibits the best catalytic ability at a pyrolysis temperature of 600 °C with a catalyst-to-lignin weight ratio of 2. The yields of bio-oil and monocyclic aromatic hydrocarbons (benzene, toluene, and xylene) can respectively reach 30.2 wt% and 1.6 wt%, which is slightly lower than those of the commercial HZSM-5 catalyst (31.7 wt% and 1.9 wt%). We also prove that the M−O−M bonds formed between oxygenophilic metals can generate electron holes as the temperature increasing. Those holes may combine with C-O bonds of phenolic compounds to generate metal–oxygen–carbon (M−O−C) bonds, facilitating the deoxygenation of lignin-derived pyrolysis vapours. These findings may provide guidance for the design of novel solid Lewis acid catalysts for the direct deoxygenation of lignin for the preparation of aromatic compounds. [ABSTRACT FROM AUTHOR]

Metal/metal oxide nano systems (M-NSs) of tunable and manipulative properties are emerging suitable for cancer management via immunity development, early-stage diagnosis, nanotherapeutics, and targeted drug delivery systems. However, noticeable toxicity, off-targeted actions, lacking biocompatibility, and being expensive limit their acceptability. Moreover, involving high energy (top-down routes) and hazardous chemicals (bottom-up chemical routes) is altering human cycle. To manage such challenges, biomass (plants, microbes, animals) and green chemistry-based M-NSs due to scalability, affordability, are cellular, tissue, and organ acceptability are emerging as desired biogenic M-NSs for cancer management with enhanced features. The state-of-art and perspective of green metal/metal oxide nano systems (GM-NSs) as an efficient anti-cancer agent including, imaging, immunity building elements, site-specific drug delivery, and therapeutics developments are highlighted in this review critically. It is expected that this report will serve as guideline for design and develop high-performance GM-NSs for establishing them as next-generation anti-cancer agent capable to manage cancer in personalized manner. [ABSTRACT FROM AUTHOR]

We have fabricated and tested in long-term field operating conditions a wireless unit for outdoor air quality monitoring. The unit is equipped with two multiparametric sensors, one miniaturized thermo-hygrometer, front-end analogical and digital electronics, and an IEEE 802.15.4 based module for wireless data transmission. Micromachined platforms were functionalized with nanoporous metal-oxides to obtain multiparametric sensors, hosting gas-sensitive, anemometric and temperature transducers. Nanoporous metal-oxide layer was directly deposited on gas sensing regions of micromachined platform batches by hard-mask patterned supersonic cluster beam deposition. An outdoor, roadside experiment was arranged in downtown Milan (Italy), where one wireless sensing unit was continuously operated side by side with standard gas chromatographic instrumentation for air quality measurements. By means of a router PC, data from sensing unit and other instrumentation were collected, merged, and sent to a remote data storage server, through an UMTS device. The whole-system robustness as well as sensor dataset characteristics were continuously characterized over a run-time period of 18 months.

Recently one dimensional (1-D) nanostructured metal-oxides have attracted much attention because of their potential applications in gas sensors. 1-D nanostructured metal-oxides provide high surface to volume ratio, while maintaining good chemical and thermal stabilities with minimal power consumption and low weight. In recent years, various processing routes have been developed for the synthesis of 1-D nanostructured metal-oxides such as hydrothermal, ultrasonic irradiation, electrospinning, anodization, sol-gel, molten-salt, carbothermal reduction, solid-state chemical reaction, thermal evaporation, vapor-phase transport, aerosol, RF sputtering, molecular beam epitaxy, chemical vapor deposition, gas-phase assisted nanocarving, UV lithography and dry plasma etching. A variety of sensor fabrication processing routes have also been developed. Depending on the materials, morphology and fabrication process the performance of the sensor towards a specific gas shows a varying degree of success. This article reviews and evaluates the performance of 1-D nanostructured metal-oxide gas sensors based on ZnO, SnO2, TiO2, In2O3, WOx, AgVO3, CdO, MoO3, CuO, TeO2 and Fe2O3. Advantages and disadvantages of each sensor are summarized, along with the associated sensing mechanism. Finally, the article concludes with some future directions of research.

This work is to summarise briefly the history of the development of semiconductor gas sensors from the point of view of a researcher working in that field through several decades. Statistical evaluation of publication trends, literature review, device technology and theory of operation are included as well as some recent and earlier results of the author and his colleagues and friends working in the field of semiconductor gas sensors. The rapid development of material science and semiconductor technology had a strong effect on gas sensor technology in the past. This trend may be extrapolated to the future; the “More than Moore” principle will be valid in the semiconductor gas sensor field too. [ABSTRACT FROM AUTHOR]

The growth in industrialization ultimately enhances the toxic discharges of wastewater containing hazardous dyes from various industrial units as a consequence severe ecological and public health issue exhibit a major challenge to conventional system to decontaminate water. Depending upon experimental constrains various physicochemical and biological treatment process have been made possible to remove pollutant of interest according to their functional abilities. In spite of all the treatment techniques, Adsorption process is considered one of the most excellent option due to the cost-effectiveness, ease of operation, high removal efficiency and regeneration of adsorbents. Over the decades, metal oxides and their composites-based absorbents showed tremendous efficiency in wastewater decontamination by dyes. The ample surface-active sites, tunable surface chemistry, ease to synthesize and functionalization, high accessible surface area, economic viability, and good recyclability make the metal oxide-based nanomaterials potential adsorbents for fast and effective removal of a wide range of heavy metal and metalloid ions. The presence of toxic dye molecules in water system poses a serious threat to aquatic ecosystem. This paper comprehensively reviews the source of contamination, possible health hazards, and adsorption technique by metal oxides to eliminate dyes from wastewater. Also, an environmentally friendly and self-sustainable treatment method should be explored to address this problem for emerging contaminants. [ABSTRACT FROM AUTHOR]

• Sustainable water etchant-based photopatterning method is proposed for sol–gel oxide films. • Patterning process remarkablely minimize trap states of dielectric and semiconductor oxide films. • Frequency-stable capacitors with low leakage current are fabricated by using low-defect AlO x. • Low-defect InO x based TFTs with exceptional electrical performance and uniformity are fabricated. • 3-V operating high-performance TFTs are fabricated at a low processing temperature of 250 °C. A sustainable water etchant-based photopatterning method is proposed to achieve simultaneous oxide film patterning and remarkably minimize trap states of dielectric and semiconductor oxide films. By exquisitely controlling each processing parameter, well-defined aluminum oxide (AlO x) dielectric and indium oxide (InO x) semiconductor patterns are formed, despite using acid-free pure water etchant. The water etchant not only dissolves the nonultraviolet-irradiated regions but also promotes an effective hydrolysis reaction of irradiated regions, thereby forming low-defect oxide patterns. As a result, frequency-stable AlO x capacitors with low leakage current and high-performance bias-stable InO x TFTs with low activation energy are fabricated. In particular, photopatterned enhancement-mode InO x TFTs exhibit remarkably improved electrical properties, stability, and uniformity—15-fold higher saturation mobility and remarkably low coefficient of variation of 12.04 cm2 V−1 s−1 and 25.26%, respectively— compared with nonpatterned TFTs. With the proposed method, 3-V operating high-performance InO x /AlO x TFTs are successfully fabricated at a low processing temperature of 250 °C. [ABSTRACT FROM AUTHOR]

pH sensors are widely used in chemical and biological applications. Metal oxides-based pH sensors have many attractive features including insolubility, stability, mechanical strength, electrocatalyst and manufacturing technology. Various metal oxide thin films prepared by radio frequency (R.F.) magnetron sputtering have attractive features, including high pH sensitivity, fast response, high resolution, good stability and reversibility as well as potential for measuring pH under conditions that are not favourable for the commonly used glass electrodes-based pH sensors. In addition, thin film pH sensors prepared by R.F. magnetron sputtering offer many advantages, such as ease of packaging, low cost through the use of standard microfabrication processes, miniaturisation, capability of measuring pH at high temperatures, ruggedness and disposability. In this paper, recent development of R.F. magnetron sputtered thin films for pH sensing applications are reviewed. [ABSTRACT FROM AUTHOR]

The hydropyrolytic method was used to prepare samples of tin dioxide films without the doping additive, and also tin dioxide films with additives containing copper oxides and copper with gold. It was shown that by using doping additives it is possible to effectively control the ratio of the area of the film surface to its volume and, consequently, the adsorption ability of the sensor material. [ABSTRACT FROM AUTHOR]