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Surface water contamination by dye pollutants is a global environmental concern. The treatment of effluent from textile waste using metal oxide-based photocatalysts is a widely employed approach owing to its efficacy and simplicity. Herein, the synthesis and fabrication of novel visible radiation receptive manganese oxide and mesoporous silica nanocomposites (Mn 2 O 3 /SiO 2) is described. Surface morphology of nanocomposites using scanning electron microscopy (SEM) displayed spherical shaped agglomerated structure. The chemical composition of nanocomposites was examined by using energy dispersive x-ray (EDX) analysis respectively indicating the presence of respective elements. Structural analysis was carried out by using XRD spectroscopy, while optical properties were evaluated by employing UV–visible spectroscopy. The photocatalytic activity of pure Mn 2 O 3 and SiO 2 nanoparticles as well as their nanocomposites with two different ratios Mn 2 O 3 /SiO 2 (1:3) and Mn 2 O 3 /SiO 2 (3:1) were evaluated by using methyl orange (MO) as a model dye. The band gap energy of Mn 2 O 3 /SiO 2 (1:3) and Mn 2 O 3 /SiO 2 (3:1) nanocomposite was 2.39 eV and 1.69 eV respectively. The nanocomposites exhibited improved photocatalytic efficiency as compared to pure nanoparticles as a function of pH and mixing ratio. For instance, at pH 7.0, Mn 2 O 3 /SiO 2 (1:3) nanocomposite has depicted maximum degradation efficiency of 68 % for degradation of MO as compared to Mn 3 O 4 /SiO 2 (3:1) nanocomposite, Mn 3 O 4 and SiO 2 nanoparticles. However, at pH 2.0 Mn 2 O 3 /SiO 2 (3:1) nanocomposite had shown maximum degradation efficiency of 99 % as compared to Mn 2 O 3 /SiO 2 (1:3), Mn 2 O 3 and SiO 2 nanoparticles. The degradation reaction followed pseudo first order kinetics. At pH 7.0, the rate constant values of nanocomposites i.e. Mn 2 O 3 /SiO 2 (1:3) and Mn 2 O 3 /SiO 2 (3:1) comes out to be 4.68 × 10−3 min−1 and 2.49 × 10−3 min−1 respectively. At pH 2.0, the rate constant values calculated for Mn 2 O 3 /SiO 2 (1:3) nanocomposite and Mn 2 O 3 /SiO 2 (3:1) nanocomposite was 4.91 × 10−3 min−1 and 1.24 × 10−2 min−1 respectively. The easy fabrication of these nanocomposites coupled with facile tuning of their properties make them suitable contenders for efficient dye degradation in wastewater treatment. [ABSTRACT FROM AUTHOR]

Refractory metal oxides such as titanium dioxide (TiO 2), tantalum oxide (Ta 2 O 5), and niobium oxide (Nb 2 O 5) coated-titanium and its alloys for medical applications have recently gained significant attention due to their remarkable properties, including high hardness, strong chemical inertness, and excellent biocompatibility. However, comparative studies among them remain scarce. In this study, thin films of Ta 2 O 5 , Nb 2 O 5 , and TiO 2 were deposited on Ti6Al4V titanium alloy using radio frequency sputtering technology. Their properties were comparably evaluated through a series of tests, including scratching, nanoindentation, friction and wear, potentiodynamic polarization, and cell cultivation experiments. The results revealed that all three coatings, with a thickness of approximately 2.6–2.8 μm, exhibited an amorphous columnar growth pattern with dense surfaces resembling cauliflower. The bonding force of the TiO 2 coating exceeds 50 N, which is 26.2 times and 14.5 times greater than that of Ta 2 O 5 and Nb 2 O 5 , respectively. Furthermore, all coated samples demonstrate superior wear resistance, corrosion resistance, and biocompatibility compared to bare Ti6Al4V. Among the coatings, TiO 2 showed the best performance, followed by Ta 2 O 5 , while Nb 2 O 5 exhibited the least favorable performance. These findings revealed the performance differences among the three ceramic coatings on Ti6Al4V samples and offer valuable insights for further research and the selection of coatings to enhance the properties of Ti6Al4V titanium alloy for biomedical applications. [ABSTRACT FROM AUTHOR]

We have shown that the adsorption of Cu2+ ions on various metal oxides, depending on the pH of the solution, can be described assuming the formation of only two surface complexes with surface hydroxyl groups SOH: SOCu(OH) and SOCu+. Using an ion-selective electrode for Cu2+, we determined the adsorption edges, i.e., the dependence of the amount of adsorbed metal expressed as a percentage depending on the solution pH for three oxides: TiO2, Al2O3, and SiO2. The measurements were carried out with high surface coverage where the ratio of the adsorption sites/copper ions in the system were from 2 to 3, depending on the oxide. Simultaneously, with the adsorption edge, the hydrogen surface charge density and the electrokinetic potential of the oxide particles were measured as a function of pH. These three types of experimental data were fitted all together using the surface complexation model (2-pK TLM). In modeling, it was not necessary to consider the precipitation of Cu(OH)2 on the oxide surface to obtain good agreement with the data. Additionally, it was shown that the presence of charged surface species SOCu+ (about 10% of total adsorbed copper) was crucial to fit the data for zeta potential. [ABSTRACT FROM AUTHOR]

Due to population growth and global technological development, energy consumption has increased exponentially. The global energy crisis opens up many hotly debated topics regarding energy generation and consumption. Not only is energy production in short supply due to limited energy resources but efficient and sustainable storage has become a very important goal. Currently, there are energy storage devices such as batteries, capacitors, and super-capacitors. Supercapacitors or electrochemical capacitors can be very advantageous replacements for batteries and capacitors because they can achieve higher power density and energy density characteristics. The evolution and progress of society demand the use of innovative and composite nanostructured metal oxide materials, which fulfill the requirements of high-performance technologies. This review mainly addresses the synthesis techniques and properties of 2D and 3D metal oxide nanostructured materials, especially based on Ti, Fe, Ga, and Sn ions, electrochemical methods used for the characterization and application of 2D, and 3D nanostructured metal oxide structures in electrochemical storage systems of energy. [ABSTRACT FROM AUTHOR]

A comparative study of the Gd2O3:Tb and Y2O3:Tb nanoparticles (NPs) was presented to examine the influence of the host lattices on the crystallographic phase, surface characteristics, optical properties, Raman effect, and photoluminescence properties. Cubic shapes Gd2O3:Tb and Y2O3:Tb NPs with an estimated crystalline size of 17 and 11 nm were recorded from the X‐ray diffraction pattern, respectively. Comparative absorption spectra of both oxides NPs were presented to examine the dispersibility, colloidal stability, and optical behavior of the NPs. Energy bandgap values were estimated to monitor the optical characteristics of the metal oxides in the UV/Vis region. Fourier transform infrared was recorded to confirm the surface‐attached water and organic moieties. The Raman spectra of metal oxides were recorded to examine the symmetrical dis‐order and polarizability of the vibrational bands. The ionic radius of the atoms distorts the bond structure resulting in it greatly influenced the vibrational bands of the materials. The emission spectra certified the effective doping of the luminescent Tb3+‐ion in the metal oxide host lattices. Raman spectra and emission spectra validated the crystal symmetry imperfections; subsequently, the efficiency of the Raman active modes and emission transitions was greatly influenced. In a comparative analysis, Y2O3:Tb NPs exhibited higher luminescence intensity in comparison with the Gd2O3:Tb NPs. [ABSTRACT FROM AUTHOR]

[Display omitted] Water splitting is a promising technique for clean hydrogen production. To improve the sluggish hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), the development of efficient bifunctional electrocatalysts for both HER and OER is urgent to approach the scale-up applications of water splitting. Nowadays transition metal oxides (TMOs) are considered as the promising electrocatalysts due to their low cost, structural flexibility and stability, however, their electrocatalytic activities are eager to be improved. Here, we synthesized waxberry-like hydrophilic Co-doped ZnFe 2 O 4 electrocatalysts as bifunctional electrocatalysts for water splitting. Due to the enhanced active sites by electronic structure tuning and modified super-hydrophilic characteristics, the spinel ZFO-Co 0.5 electrocatalyst exhibits excellent catalytic activities for both OER and HER. It exhibits a remarkable low OER overpotential of 220 mV at a current density of 10 mA cm−2 and a Tafel slope of 28.2 mV dec-1. Meanwhile, it achieves a low overpotential of 73 mV at a current density of 10 mA cm−2 with the Tafel slope of 87 mV dec-1 for HER. In addition, for water electrolysis device, the electrocatalytic performance of ZFO-Co 0.5 ||ZFO-Co 0.5 surpasses that of commercial IrO 2 ||Pt/C. Our work reveals that the hydrophilic morphology regulation combined with metallic doping strategy is a facile and effective approach to synthesize spinel TMOs as excellent bifunctional electrocatalyst for water splitting. [ABSTRACT FROM AUTHOR]

The rise of flexible and wearable electronics has spurred advancements in printed, flexible micro-supercapacitors for energy storage. This study presents the fabrication of flexible micro-supercapacitors using a novel nanocomposite of tin dioxide grown on layered reduced graphene oxide through one-pot in situ synthesis. The conductive functional ink, formulated by mixing the nanocomposite, is effectively utilized in screen-printing technology. The resulting micro-supercapacitors, particularly the SG-1 variant, demonstrate impressive electrochemical performance. The nanocomposites show exceptional versatility across various electrolytes, including alkaline, acidic, and quasi-gel electrolytes with a polyvinyl alcohol matrix infused with potassium hydroxide. An in-depth comparison of their efficacy in these electrolytes highlights the most suitable configurations for optimal performance. At a scan rate of 5 mV s−1, SG-1 achieves areal capacitances of 148.7 mF cm−2 and 87.7 mF cm−2 in the 1 M KOH and polyvinyl alcohol infused with 1 M KOH quasi-gel electrolyte. Additionally, SG-1 in the gel electrolyte demonstrates remarkable energy density of 11.7 mWh cm−2 at power density of 490 mW cm−2. Notably, the fabricated micro-supercapacitors exhibit excellent capacitive retention of 89.5% even after undergoing 5000 cycles of charge–discharge, underscoring their robustness and long-term stability for practical applications in flexible and wearable electronics. [ABSTRACT FROM AUTHOR]

Antibiotic consumption is growing more widespread worldwide and so is the problem of antibiotic resistance. According to reports, the projected world's consumption of antibiotics by 2030 in terms of defined daily dosages (DDD) is 200 % higher than 42 billion DDD's consumed in 2015 (Klein et al. in Proc Natl Acad Sci U S A 115:E3463–E3470, 2018). Drug-resistant infections pose a serious concern to public health management especially in the backdrop of severe economic strain ever since the outset of COVID-19 pandemic. Metal oxide nanoparticles (MONPs) have proven their credentials in biomedicine due to their unique properties compared to their bulk metallic counterparts. In the present review, we have briefly compiled the methods of synthesis of novel antimicrobial MONPs, and the diverse MONPs that have been reported for their antibiotic application have been presented. The cascade of mechanisms behind the antibiotic activity of MONPs has been listed with specific mentions of the site-specific mechanisms that are operational. The challenges, as well as lapses in the current knowledge in this area of research, have been discussed and recommendations for expanding its application proposed. [ABSTRACT FROM AUTHOR]

This study investigates the potential of pomegranate peel (PP) as a raw material for synthesizing a novel biocatalyst metal oxide (BCMO) aimed at the efficient removal of methyl orange (MO) dye from aqueous solutions. The adsorption capacities of both PP and BCMO were systematically evaluated. PP was subjected to inorganic salt treatment and calcination to enhance its adsorption capacity and increase attractive forces at the nanoparticle level. The surface characteristics of the biocatalyst were thoroughly examined using FTIR, SEM, BET analysis, and EDX spectroscopy, revealing the development of a crystalline structure following treatment with Mg(NO3)2⋅6H2O, along with observable changes in surface morphology and elemental composition. Under standard conditions, BCMO demonstrated a significant increase in efficiency, achieving 99.80% removal for 100 mg/L of methyl orange, compared to 44% for untreated PP at 50 mg/L. Kinetic analysis indicated a transition from pseudo-first-order to pseudo-second-order, signifying a shift from physical to chemical adsorption. This transition resulted in a substantial reduction in equilibrium time and a significant increase in maximum adsorption capacity from 17.3637 to 176.686 mg/g. Furthermore, the catalytic efficiency of BCMO was assessed over seven cycles, showing only a minor 5% reduction in efficiency, indicating its potential for practical applications. The environmental sustainability of the road was assessed using the AGREE and BAGI indicators, both of which are considered exemplary measures of environmental friendliness. [ABSTRACT FROM AUTHOR]

Molybdenum trioxide (α‐MoO3) is a promising and inexpensive alternative to platinum group metals (PGMs), for electrocatalytic hydrogen evolution reaction (HER). However, to make it a viable candidate for electrocatalytic systems, we must address the hurdles associated with its inferior electrical conductivity and lack of active sites. Unlike Mo‐based compounds such as MoS₂ and MoSe₂, which possess catalytically active edges, α‐MoO₃ lacks inherent active sites for HER. Previous studies have employed various strategies to activate MoO₃ for HER, yet its activation in near‐neutral conditions remain largely unexplored. In this study, a previously known α‐MoO3 intercalating {Ni(H2O)6}2+, [MoVI2O6(CH3COO){NiII(H2O)6}0.5] ⋅ H2O (Ni(H2O)6@MoO3) is prepared via a simple and scalable room‐temperature aqueous synthesis. In the subsequent aerial thermal annealing process at 300, 400 and 500 °C, Ni(H2O)6@MoO3 acts as a self‐sacrificial template, yielding mixed metal oxide composites of nickel and molybdenum (named as MoO3‐300, MoO3‐400 and MoO3‐500). The HR‐TEM and XPS analyses confirm the formation of the Ni2O3 phase alongside the orthorhombic α‐MoO3. The annealing temperature plays a key role in the crystallinity, phase, morphology, and electrocatalytic performance of the resulting composites. The composite formed at 400 °C (MoO3‐400) shows the best electrocatalytic performance among them, showcasing a fivefold enhancement in the HER current density as compared to that shown by commercially available α‐MoO3 in mildly acidic acetate buffer. The enhanced performance towards HER by MoO3‐400 could be attributed to the nanostructured morphology attained via thermal treatment, which provides greater access to the surface sites and the synergistic interaction between the nickel oxide phases and MoO₃ structure, enabling an intermediate pH HER activity rarely reported for molybdenum oxide materials. [ABSTRACT FROM AUTHOR]

In this study, we demonstrate the emergence of NO2 gas sensing capabilities in the typically non-active NiWO4, a strongly correlated electron system (SCES), by introducing substitutional Fe at the Ni site. NiWO4 typically exhibits strong Coulombic repulsion between Ni atoms, resulting in a large band gap of over 3.0 eV and insulating behavior. This correlated behavior is clearly reflected in the significant increase of band gap when considering the Hubbard U correction for the cations, bringing the theoretical value closer to the observed value. The single-phase Fe0.5Ni0.5WO4 displays a notable shift in the [NiO6] symmetric vibration mode and an increase in magnetization. Additionally, theoretical calculations confirm the preservation of the wide band gap, with the Fe and O levels generated within the band gap. These findings indicate that Fe located in the Ni sites modulate Coulombic repulsion in NiWO4 SCES insulators. Unlike the poor gas-sensing performance of intrinsic NiWO4, Fe0.5Ni0.5WO4 exhibits a significant NO2 response (Rg/Ra) of 11 at 200°C than other gases and a limit of detection (LOD) of 46.4 ppb. This study provides a pathway for realizing gas-sensing performance in strongly correlated electron insulators with large band gaps through the introduction of dopant levels at the cation sites. [ABSTRACT FROM AUTHOR]

High density, skin effect, and environmental instability are significant limitations that restrict the application of metal-based microwave absorbers in achieving lightweight, high performance, and long service life. This study broke from traditional methods for preparing a microwave absorber Mn 2 O 3 -Fe 3 O 4 @PPy (polypyrrole) by employing an innovative annealing process to convert metal into metal oxide by the introduction of metal organic framework (MOF), which effectively achieving a more lightweight absorber material with hollow porous nanocube structure. Subsequently, PPy was coated onto the metal oxide surface to form a core-shell structure by a situ chemical oxidation synthesis method. The combination of metal oxide of the hollow porous nanocube structure and the core-shell structure formed by highly conductive PPy shell significantly enhanced heterogeneous interfaces and electromagnetic (EM) wave reflection. Excellent dielectric loss and impedance matching contributed evidently to the ultra-wideband EM wave absorption performance. It was demonstrated that, with a filling amount of only 20 wt%, the prepared Mn 2 O 3 -Fe 3 O 4 @PPy achieved an effective bandwidth (EAB) of 10.0 GHz at a thickness of 3.08 mm, with EAB max reaching 13 GHz. At a filling amount of only 10 wt%, the reflection loss (RL) was −62.13 dB, achieving an EAB of 7.4 GHz at 2.98 mm thickness, with EAB max reaching 11.4 GHz. Furthermore, the proposed strategy incorporating metal oxide and PPy enhanced corrosion resistance with higher charge transfer resistance. The ultra-wideband microwave absorption material uses an innovative annealing process for MOF, and then ingenious combines with the coated PPy to form a hollow porous nanocube core-shell structure. Excellent microwave absorption performance: EAB max = 13 GHz, RL min = −62.13 dB, low fill of 10 wt%. In addition, the corrosion resistance of the metal is improved. [Display omitted] [ABSTRACT FROM AUTHOR]

In the present research, it is reported that ball milling technique can be applied to enhance the photocatalytic properties of MnO and ZrO 2 metal oxide powders (MZOx) furthermore the fabricated photocatalyst can be used for the degradation of tetracycline (TTC). XRD analyses revealed that increasing the milling time resulted in the formation of a pure metallic Mn crystal phase, which boosted the antibiotic degradation rate. It was confirmed by SEM technique that the morphological structures of the particles were generally small and uniform. The band gap energy was calculated as 3.70 eV for the hybrid metal oxide. Additionally, the adsorptive and photoluminescence features were illuminated via DRS and PL analyses. The effect of milling time had a major impact on the photodegradation rate of TTC, and the 8 h milling sample (MZOx-8h) exhibited the highest catalytic degradation activity (79.4 %). Low photocatalytic activity was obtained at acidic pHs and increased at alkaline pHs. The presence of H 2 O 2 sharply decreased photocatalytic process time (60 min) and 94.3 % of the TTC was degraded at 7.5 mM H 2 O 2. The photocatalytic degradation process proceeded through superoxide radicals and was supported by holes. The stability of MZOx-8h almost remained constant (70.02 %) even after seven cycles. It was determined that the presence of oxalic acid positively affected the progress of TTC degradation reactions. Further, practical application areas were investigated and MZOx-8h doped on support materials was found to be suitable for such applications in proportion to the doping ratio. Finally, it was demonstrated that MZOx-8h exhibited remarkable performance in photocatalytic reactions of different types of organic pollutants. The synergistic nature of MnO and ZrO 2 with the contribution of ball milling time effect resulted in high photocatalytic activity. • High purity metallic Mn phase was successfully synthesized by ball-milling. • MZOx was used for the first time in TTC photodegradation. • TTC degradation was stable in the seventh cycle. • The different organic pollutants were removed with high efficiency. [ABSTRACT FROM AUTHOR]

The demand for gas-sensing operations with lower electrical power and guaranteed sensitivity has increased over the decades due to worsening indoor air pollution. In this report, we develop room-temperature operational NH3 gas-sensing materials, which are activated through electron doping and crystal structure distortion effect in Fe0.2Ni0.8WO4. The base material, synthesized through solid-state synthesis, involves Fe cations substitutionally located at the Ni sites of the NiWO4 crystal structure and shows no gas-sensing response at room temperature. However, doping Na into the interstitial sites of Fe0.2Ni0.8WO4 activates gas adsorption on the surface via electron donation to the cations. Additionally, the hydrothermal method used to achieve a more than 70-fold increase in the surface area of structure-distorted Na-doped Fe0.2Ni0.8WO4 powder significantly enhances gas sensitivity, resulting in a 4-times increase in NH3 gas response (Rg/Ra). Photoluminescence and XPS results indicate negligible oxygen vacancies, demonstrating that cation contributions are crucial for gas-sensing activities in Na-doped Fe0.2Ni0.8WO4. This suggests the potential for modulating gas sensitivity through carrier concentration and crystal structure distortion. These findings can be applied to the development of room-temperature operational gas-sensing materials based on the cations. [ABSTRACT FROM AUTHOR]

The demand for gas-sensing operations with lower electrical power and guaranteed sensitivity has increased over the decades due to worsening indoor air pollution. In this report, we develop room-temperature operational NH3 gas-sensing materials, which are activated through electron doping and crystal structure distortion effect in Fe0.2Ni0.8WO4. The base material, synthesized through solid-state synthesis, involves Fe cations substitutionally located at the Ni sites of the NiWO4 crystal structure and shows no gas-sensing response at room temperature. However, doping Na into the interstitial sites of Fe0.2Ni0.8WO4 activates gas adsorption on the surface via electron donation to the cations. Additionally, the hydrothermal method used to achieve a more than 70-fold increase in the surface area of structure-distorted Na-doped Fe0.2Ni0.8WO4 powder significantly enhances gas sensitivity, resulting in a 4-times increase in NH3 gas response (Rg/Ra). Photoluminescence and XPS results indicate negligible oxygen vacancies, demonstrating that cation contributions are crucial for gas-sensing activities in Na-doped Fe0.2Ni0.8WO4. This suggests the potential for modulating gas sensitivity through carrier concentration and crystal structure distortion. These findings can be applied to the development of room-temperature operational gas-sensing materials based on the cations. [ABSTRACT FROM AUTHOR]

This study explores the application of Atomic Layer Deposition (ALD) to functionalize high-surface-area carbon supports with metal and metal oxide films and particles for applications in catalysis and electrocatalysis. The work reported here demonstrates that, through careful choice of precursors and absorption and reaction conditions, self-limited ALD growth on a high-surface-area carbon support can be achieved. Specific examples presented include the growth of conformal films of ZrO2 and SnO2 and the deposition of Ga2O3 and Pt particles on a carbon black support with a surface area of 250 m2·g−1. A novel strategy for controlling the Pt weight loading and producing sub-nanometer Pt particles on a carbon support using a single ALD cycle is also presented. [ABSTRACT FROM AUTHOR]

We are proposing a novel self-assembled monolayer (SAM) functionalized ZnO nanowires (NWs)-based conductometric sensor for the selective detection of hydrogen (H2). The modulation of the surface electron density of ZnO NWs due to the presence of negatively charged terminal amine groups (−NH2) of monolayers leads to an enhanced electron donation from H2 to ZnO NWs. This, in turn, increases the relative change in the conductance (response) of functionalized ZnO NWs as compared to bare ones. In contrast, the sensing mechanism of bare ZnO NWs is determined by the chemisorbed oxygen ions. The functionalized ZnO NWs exhibit an eight times higher response compared to bare ZnO NWs at an optimal working temperature of 200 °C. Finally, in comparison to studies in the literature involving strategies to enhance the sensing performance of metal oxides toward H2, like decoration with metal nanoparticles, heterostructures, and functionalization with a metal–organic framework, etc., SAM functionalization showed superior sensing results. [ABSTRACT FROM AUTHOR]

Utilization of actinides and rare earth elements is only possible by separating these metals with high purity. The materials used in separation must have thermal, chemical, mechanical, and radiation resistance. In the present study, separation experiments of actinides and rare earth elements (REEs) were carried out using purified H2SO4 leach liquor. Polyacrylonitrile (PAN)-supported Ti, Zr, and Si oxide nanocomposites were tested for the selective separation of Th, U, Gd, Eu, Sm, Pr, Nd, La, Ce, and Y. The effects of pH, contact time, adsorbent/solution ratio, and temperature on distribution coefficient (KD) and adsorption capacity (Q) were investigated. The synthesized nanocomposites tend to separate the elements into two main groups: Th, U, Gd, Eu and Sm, Pr, Nd, La, Ce. Notably, it was observed that the separation of Th and U from the remaining elements is promising at 15 °C. Additionally, the separation can be further improved depending on the differences in desorption efficiency. [ABSTRACT FROM AUTHOR]

The in-situ electrochemically reconstructed Cu 2 O/CeO 2 from CuO/CeO 2 has been demonstrated to be effective for electrocatalytic carbon dioxide reduction, delivering a high selectivity, activity, and stability for producing CH 4. [Display omitted] Developing an efficient electrocatalyst that enables the efficient electrochemical conversion from CO 2 to CH 4 across a wide potential range remains a formidable challenge. Herein, we introduce a precatalyst strategy that realizes the in situ electrochemical reconstruction of ultrafine Cu 2 O nanodomains, intricately coupled on the CeO 2 surface (Cu 2 O/CeO 2), originating from the heterointerface comprised of ultrafine CuO nanodomains on the CeO 2 surface (CuO/CeO 2). When served as the electrocatalyst for the electrochemical CO 2 reduction reaction, Cu 2 O/CeO 2 delivers a selectivity higher than 49 % towards CH 4 over a broad potential range from −1.2 V to −1.7 V vs. RHE, maintaining negligible activity decay for 20 h. Notably, the highest selectivity for CH 4 reaches an impressive 70 % at −1.5 V vs. RHE. Through the combination of comprehensive analysis including synchrotron X-ray absorption spectroscopy, spherical aberration-corrected high-angle annular dark field scanning transmission electron microscope as well as the density functional theoretical calculation, the efficient production of CH 4 is attributed to the coherent interface between Cu 2 O and CeO 2 , which could converted from the original CuO and CeO 2 interface, ensuring abundant active sites and enhanced intrinsic activity and selectivity towards CH 4. [ABSTRACT FROM AUTHOR]

The conversion of ambient mechanical vibrations into electricity using piezoelectric nanogenerators (PENGs) has garnered significant attention from researchers over the past few years, in light of its potential in wearable applications. The high flexibility and significant ferroelectricity of poly(vinylidene fluoride) (PVDF) make them the most promising candidates for PENG applications among polymer piezoelectric materials. In the present work, NiO nanoparticles were incorporated in different ratios into a PVDF matrix, and their potential for use in piezoelectric nanogenerators was investigated. The PVDF/NiO (5 wt.%) nanocomposite PENG exhibited the highest electrical output, with a 2.8-fold increase in open-circuit voltage and short-circuit current observed as compared to a bare PVDF-based PENG. However, a further increase in the compositional ratio of NiO led to a decrease in PENG output. The improved piezoelectricity in the PVDF/NiO (5 wt.%) nanocomposite is attributed to the enhanced polar phases and improved ferroelectricity of PVDF. Further confirmation of the improved piezoresponse was explored by measurement of the piezoelectric coefficient (d33) and dielectric study of the nanocomposites. The PENG electrical output was further simulated using the finite elemental method in COMSOL Multiphysics 5.5. The simulated results matched well with the experimental output, which confirmed the improved electrical performance of the PVDF/NiO nanocomposite-based PENGs. The enhanced performance of the nanocomposite PVDF film is attributed to the higher β phase in the PVDF. The efficiency of the PENG devices in motion-sensing applications was also explored. Different output voltage signals corresponding to different movements of the nanocomposite-based PENGs make the device compatible with sensor applications. [ABSTRACT FROM AUTHOR]

Sol-Gel synthesis of metal oxides constitutes a tremendously exciting domain of inorganic chemistry, where molecular and supramolecular science meet the physical chemistry and materials science. Structure and reactivity, especially surface complexation of biologically important molecules on the surface of metal oxide nanoparticles can efficiently be traced through structural studies of metal oxo-paperbags—the product of partial hydrolysis of alkoxide precursors. Paperbag is a recently proposed term to denote oligonuclear complexes not featuring intrinsic metal-metal bonding and thus not qualified to be called "clusters". Another important insight, provided recently by the studies of heterometallic species, is dealing with visualization of bonding modes of single atom catalysts on metal oxide substrates and reveals possible coordination environments of heteroatoms on doping. The studies of large paperbag aggregates can contribute to understanding of factors influencing the bandgap and photocatalytic activity of related oxides. The use of these species directly as photo or electro catalysts is rather debatable, however, in the view of high reactivity of these alkoxide intermediates, easily transforming them into metal oxide nanoparticles on hydrolysis or thermolysis. Highlights: Metal alkoxides form easily Oligonuclear Alkoxide Complexes, OAC, with metal-oxygen core structures resembling those of metal oxides. The structures of OAC result from two major factors – dense packing of cations and anions, and minimization of the surface energy. OAC provide good insights into redox reaction mechanisms of metal oxide nanoparticles and in coordination of surface-implanted heteroatoms. OAC are not clusters but paperbags, making direct studies of their reactivity in aqueous medium challenging. [ABSTRACT FROM AUTHOR]

We conducted experiments utilizing the scattering effect of zinc oxide (ZnO) to enhance the photoluminescence (PL) intensity of cesium lead bromide (CsPbBr3) perovskite quantum dots (QDs). This study involved investigating the method for creating a CsPbBr3 and ZnO mixture and determining the optimal mixing ratio. A mixture dispersion of CsPbBr3 and ZnO, prepared at a 1:0.015 weight ratio through shaking, was fabricated into a film using the spin coating method. The PL intensity of this film showed a relative increase of 20% compared to the original CsPbBr3 QD film without ZnO. The scattering effect of ZnO was confirmed through ultraviolet-visible (UV-Vis) absorption and transient PL experiments, and a long-delayed exciton lifetime was observed in the optimized mixture dispersion thin film. The morphology of the fabricated film was characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). For the CsPbBr3-ZnO mixture (1:0.0015) film, crystal domains of approximately 10 nm were observed using TEM. Through AFM analysis, an excellent film roughness of 4.6 nm was observed, further confirming the potential of perovskite QD/ZnO composite films as promising materials for enhanced photoconversion intensity. In future studies, applying this method to other perovskite materials and metal oxides for the optimization of photoconversion composite materials is expected to enable the fabrication of highly efficient perovskite QD/metal oxide composite films. [ABSTRACT FROM AUTHOR]

ABSTRACT To tackle the challenge of non‐destructively analyzing complex oxide layers formed by atmospheric corrosion on active metals, we investigate the potential of inverse spatially offset Raman spectroscopy (inverse‐SORS) to detect corrosion products and elucidate how the spectroscopic features of SORS vary. This study explores the utilization of inverse‐SORS technology for longitudinal structural analysis of opaque CeO2/La2O3 laminates, which serve as a proxy for corrosion products. Through a combination of experimental measurements and Monte Carlo simulation, it demonstrates the feasibility of inverse‐SORS in non‐destructively elucidating the layered structure of these laminates. With increasing the spatial offset of this technology, the Raman intensity ratio of La2O3‐to‐CeO2 increases from 0.23 to 3.2 and then decreases to 0.27 for the CeO2/La2O3 sample with a 34‐μm‐thick CeO2 layer under 532‐nm excitation, whereas the bottom La2O3 layer is hardly detected when the thickness of the upper La2O3 layer increases to 225 μm. The results reveal that a thinner CeO2 layer facilitates the escape and detection of Raman signals originating from the bottom La2O3 layer, leading to an enhanced La2O3‐to‐CeO2 signal ratio and a reduced offset at the characteristic peak. The research also sheds light on the intricate interplay among multiple variables, such as spatial offset, laser wavelength, the corresponding absorption factor, the thickness of the oxide layer, and the compactness. These insights suggest that SORS is a valuable and non‐destructive approach for dissecting the structures of highly turbid composites of metallic compounds and semi‐quantitatively deducing their thickness. [ABSTRACT FROM AUTHOR]

A layered Na2SnO3 with honeycomb structure was synthesized by solid state route using sodium carbonate and tin oxide. The prepared sample was characterized by different physicochemical characterization techniques like X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X‐ray spectroscopy (EDS), X‐ray photoelectron spectroscopy (XPS), ultraviolet visible spectroscopy (UV–vis), photoluminescence spectra (PL), N2 adsorption technique (Brunauer–Emmett–Teller, electrochemical impedance spectroscopy (EIS). The photodegradation of rose bengal dye under UV light was studied. Due to honeycomb structure and high surface area of Na2SnO3, the complete degradation of rose Bengal was observed in 90 min under UV light irradiation. Results of photocatalytic dye degradation reaction demonstrated that Na2SnO3 can be employed as photocatalyst under UV light irradiation. [ABSTRACT FROM AUTHOR]

A novel mixed metal oxide of CuNiO x has been successfully obtained via electrosynthesis and thermal conversion of a Hofmann-type MOF Cu(pz) 2 [Ni(CN) 4 ] (pz = pyrazine). CuNiO x has demonstrated a significant enhancement in light absorption within a visible light range, leading to an impressive increase in photocurrent density and photocatalytic activity during light irradiation compared to CuO. The exceptional photoelectrochemical properties of the photocathodes of CuNiO x have been studied using multiple photoelectrochemical instrumental techniques, which proved the electrodes were stable over the whole water photolysis. The coupling of two metal centers has explained their outstanding performance. • A novel CuNiO x photocathode derived from Hofmann-type MOF was prepared. • CuNiO x shows significant improvement in photocatalytic activity towards H 2 production. • CuNiO x outperforms CuO in hydrogen evolution due to Cu-Ni synergy. • Spectroscopic studies highlight CuO and NiO roles in charge separation. [ABSTRACT FROM AUTHOR]

To meet today's requirements, new active catalysts with reduced noble metal content are needed for hydrogen sensing. A palladium-functionalized nanostructured Ni0.5Co2.5O4 catalyst with a total Pd content of 4.2 wt% was synthesized by coprecipitation to obtain catalysts with an advantageous sheet-like morphology and surface defects. Due to the synthesis method and the reducible nature of Ni0.5Co2.5O4 enabling strong metal-metal oxide interactions, the palladium was highly distributed over the metal oxide surface, as determined using scanning transmission electron microscopy and energy-dispersive X-ray investigations. The catalyst tested in planar pellistor sensors showed high sensitivity to hydrogen in the concentration range below the lower flammability limit (LFL). At 400 °C and in dry air, a sensor response of 109 mV/10,000 ppm hydrogen (25% of LFL) was achieved. The sensor signal was 4.6-times higher than the signal of pristine Ni0.5Co2.5O4 (24.6 mV/10,000 ppm). Under humid conditions, the sensor responses were reduced by ~10% for Pd-functionalized Ni0.5Co2.5O4 and by ~27% for Ni0.5Co2.5O4. The different cross-sensitivities of both catalysts to water are attributed to different activation mechanisms of hydrogen. The combination of high sensor sensitivity to hydrogen and high signal stability over time, as well as low cross-sensitivity to humidity, make the catalyst promising for further development steps. [ABSTRACT FROM AUTHOR]

Wastewater contaminated with cadmium is a concern because of its toxicity, persistence, and bioaccumulation to the environment, ecosystem, and human health, so it is required to remove cadmium(II) ions before releasing them to receiving water. Banana powder beads (BPB), banana powder doped ZnO beads (BPZB), banana powder doped MgO beads (BPMB), and banana powder doped ZnO + MgO beads (BPZMB) were synthesized as the novel cadmium adsorbents, and their characterizations, cadmium adsorption performances, cadmium adsorption patterns and mechanisms, thermodynamic study, and reusability were investigated. BPMB had the highest specific surface area of 16.60 m2/g and the smallest pore size of 1.69 nm than other materials. BPB was an amorphous structure, whereas BPZB, BPMB, and BPZMB were crystalline structures presenting their specific metal oxide peaks of ZnO or MgO. They were coarse surfaces and had a spherical shape consisting of C, O, Ca, Cl, and Na. Their main functional groups were O–H, C–H, C=O, C–O, and N–H. The points of zero charge of BPB, BPZB, BPMB, and BPZMB were 5.37, 6.75, 9.87, and 9.43. The cadmium removal efficiencies of BPB, BPZB, BPMB, and BPZMB were 89.18%, 96.62%, 99.59%, and 97.85%, and their qm values were 90.09, 232.56, 454.55, and 303.03 mg/g, respectively. Thus, the metal oxide helped to improve material efficiency, especially MgO. The Freundlich and pseudo-second-order kinetic models were good fit models for describing their adsorption patterns and mechanisms. The increasing temperature affected to decrease their cadmium adsorptions. They could be reused in more than 3 cycles of more than 73% of cadmium adsorption. The electrostatic interaction played an important role in describing their cadmium adsorptions. Therefore, BPBM was a good cadmium adsorbent for application in industrial wastewater treatment since it had a higher performance of cadmium adsorption than other materials. [ABSTRACT FROM AUTHOR]

The detection of inert gases presents a challenging task because these molecules do not react with most known sensor-based units aimed at environment monitoring. Here, we ionize these molecules in a low-potential discharge mode to force their interaction with semiconducting SnO2 single-crystal nanobelts (NBs) deposited as a mat over a multielectrode chip and show the ion-induced resistivity changes similar to a conventional operation of the metal oxide sensor. In particular, the conductance of the percolating NB mats is significantly enhanced under irradiation with He+, Ne+, and Ar+ ions at a low-pressure oxygen background. The phenomenon is well explained via ab initio calculations performed in the framework of density functional theory (DFT), which clarify the interaction of various ions with SnO2 nanocrystals related primarily to the appearance of electronic states and redistribution of their density dependent on the kind of ions. The differences in ion interaction with the SnO2 surface is the background for options to distinguish the inert gases with a SnO2 NB-based multisensor array as a low-cost selective detector via transferring the variations in a charge exchange at the adsorbate/adsorbent interface into a varied chemiresistive vector signal like a (mass) spectrometer performs. [ABSTRACT FROM AUTHOR]

Valorizing biodegradable raw materials derived from agri‐waste is ecologically beneficial. Employing such materials to produce adsorbents is a smart platform for applications in wastewater purification. Lignin is one of the most plentiful natural biopolymers in the world. Its macromolecular structure possesses phenolic and carboxyl groups that can capture heavy metals and dyes. Lignin can be chemically and physically modified to generate adsorbent materials with enhanced capacity to remove pollutants from wastewater. In this work, lignin has been used as a natural resource to synthesize metal oxide‐based nanoadsorbents. The synthesized lignin‐based green nanomaterials effectively removed common pollutants from wastewater including dyes, heavy metals, and bacteria. The lignin‐based water purification technique holds immense potential to effectively remove the most common pollutants from wastewater. [ABSTRACT FROM AUTHOR]

The discovery of single-atom catalysts (SACs) represents a groundbreaking advancement in the field of catalysis over the past decades. With the in-depth exploration of relevant structure-activity relationships, the metal-support interaction (MSI) is widely adopted to elucidate variations in electronic structure and coordination configuration of atomic active sites on various kinds of supports. Herein, we briefly summarize the metal oxide supports for SACs fabrication, including the distinctive characteristics of metal oxide supports, enlightening advancements in metal oxide support-based SACs (MO-SACs), feasible preparation methods for MO-SACs and effective regulation strategies of MSI effect in MO-SACs. In addition, we present our viewpoints and outlook in this field to stimulate rational design and construction of novel MO-SACs applied in diverse renewable energy devices, while some universal suggestions are sincerely given to provoke thoughtful considerations during the research process. [ABSTRACT FROM AUTHOR]

Blister-based laser-induced forward transfer (BB-LIFT) is a promising high precision and resolution printing technique for the fast, solvent- and mask-free transfer of functional layered materials onto micro-devices. It utilizes a protective metal (blister) layer sandwiched between the laser-transparent substrate and the material to be transferred. The metal layer absorbs the incident laser pulse, creating a rapidly expanding blister that propels the overlying material onto a target substrate. We show that BB-LIFT of thin and ultrathin (30 and 3 nm) ZrO2 films is realized only with a "graphene release layer" applied between the Al blister layer and the ZrO2 donor layer. Without such intercalation, ZrO2 is inseparable from the blister layer due to the strong oxide bonding with aluminum oxides formed during the preparation. The ZrO2 transfer was confirmed through high-resolution scanning electron microscopy and energy-dispersive X-ray spectroscopy, affirming the critical role of graphene as a release layer. The promotion of mechanically strong, flexible graphene as a release layer can be generalized in BB-LIFT applications if thin films of fragile, polycrystalline, or amorphous metal oxides must be printed for gas sensors, catalytic, or other applications. [ABSTRACT FROM AUTHOR]

Metal oxide core–shell fibrous nanostructures are promising gas-sensitive materials for the detection of a wide variety of both reducing and oxidizing gases. In these structures, two dissimilar materials with different work functions are brought into contact to form a coaxial heterojunction. The influence of the shell material on the transportation of the electric charge carriers along these structures is still not very well understood. This is due to homo-, hetero- and metal/semiconductor junctions, which make it difficult to investigate the electric charge transfer using direct current methods. However, in order to improve the gas-sensing properties of these complex structures, it is necessary to first establish a good understanding of the electric charge transfer in ambient air. In this article, we present an impedance spectroscopy study of networked SnO2/Ga2O3 core–shell nanobelts in ambient air. Tin dioxide nanobelts were grown directly on interdigitated gold electrodes, using the thermal sublimation method, via the vapor–liquid–solid (VLS) mechanism. Two forms of a gallium oxide shell of varying thickness were prepared via halide vapor-phase epitaxy (HVPE), and the impedance spectra were measured at 189–768 °C. The bulk resistance of the core–shell nanobelts was found to be reduced due to the formation of an electron accumulation layer in the SnO2 core. At temperatures above 530 °C, the thermal reduction of SnO2 and the associated decrease in its work function caused electrons to flow from the accumulation layer into the Ga2O3 shell, which resulted in an increase in bulk resistance. The junction resistance of said core–shell nanostructures was comparable to that of SnO2 nanobelts, as both structures are likely connected through existing SnO2/SnO2 homojunctions comprising thin amorphous layers. [ABSTRACT FROM AUTHOR]

Over the last years, a wide variety of nanomaterials have been utilised for the design of highly efficient sensors to detect ammonia (NH3) accurately. Discovery of graphene has dramatically accelerated studies on fabrication of inexpensive electrode materials due to its unique features such as high specific surface area, high carrier mobility, high electrical conductivity, flexibility and optical transparency. Graphene and its derivatives can be readily combined with a variety of inorganic-based nanoparticles such as noble metals, metal oxides and semiconducting, as well as conducting polymers to develop NH3 sensor with excellent sensitivity and very low detection limit. This paper overviews graphene nanocomposite gas sensors as emerging NH3 sensing platforms for the detection of a wide range of NH3 concentration with improved sensitivity, selectivity and a low response and recovery times. Various sensing mechanisms of functionalised graphene nanocomposite gas sensors are explained and compared. Possible opportunities and perspective applications of the graphene NH3 sensors are also presented. [ABSTRACT FROM AUTHOR]

Blister-based laser-induced forward transfer (BB-LIFT) is a promising high precision and resolution printing technique for the fast, solvent- and mask-free transfer of functional layered materials onto micro-devices. It utilizes a protective metal (blister) layer sandwiched between the laser-transparent substrate and the material to be transferred. The metal layer absorbs the incident laser pulse, creating a rapidly expanding blister that propels the overlying material onto a target substrate. We show that BB-LIFT of thin and ultrathin (30 and 3 nm) ZrO2 films is realized only with a "graphene release layer" applied between the Al blister layer and the ZrO2 donor layer. Without such intercalation, ZrO2 is inseparable from the blister layer due to the strong oxide bonding with aluminum oxides formed during the preparation. The ZrO2 transfer was confirmed through high-resolution scanning electron microscopy and energy-dispersive X-ray spectroscopy, affirming the critical role of graphene as a release layer. The promotion of mechanically strong, flexible graphene as a release layer can be generalized in BB-LIFT applications if thin films of fragile, polycrystalline, or amorphous metal oxides must be printed for gas sensors, catalytic, or other applications. [ABSTRACT FROM AUTHOR]

K3Li2Ta5O15 is found as a novel photocatalyst for overall water splitting under ultraviolet light irradiation. K3Li2Ta5O15 possesses a characteristic crystal structure with Li+ ion-filled C-sites in (A1)4(A2)2C4M10O30 as the general formula of a tungsten bronze-type metal oxide. Most of the reported photocatalysts with a tungsten bronze structure possess empty C-sites. K6Ta10.8O30 also possesses a C-site-filled tungsten bronze structure in which C-sites are partially filled with Ta5+ ions. In diffuse reflectance spectra, K6Ta10.8O30 has an absorption edge at a longer wavelength than K3Li2Ta5O15. This narrower band gap of K6Ta10.8O30 than K3Li2Ta5O15 is considered to be due to the presence of Ta5+ ions at C-sites in K6Ta10.8O30. Ta5+ ions that are located at 9-fold coordination C-sites with a totally different surrounding environment from the 6-fold coordination M-sites will form the conduction band minimum at a lower potential than those located at 6-fold coordination M-sites. The optimized K3Li2Ta5O15 shows almost the same water-splitting activity as the optimized K6Ta10.8O30. Thus, it is found that the conduction band that is formed by Ta5+ ions at C-sites is also effective for photocatalytic reaction, being similar to that formed by Ta5+ ions at M-sites. [ABSTRACT FROM AUTHOR]

Abstract Wastewater contaminated with cadmium is a concern because of its toxicity, persistence, and bioaccumulation to the environment, ecosystem, and human health, so it is required to remove cadmium(II) ions before releasing them to receiving water. Banana powder beads (BPB), banana powder doped ZnO beads (BPZB), banana powder doped MgO beads (BPMB), and banana powder doped ZnO + MgO beads (BPZMB) were synthesized as the novel cadmium adsorbents, and their characterizations, cadmium adsorption performances, cadmium adsorption patterns and mechanisms, thermodynamic study, and reusability were investigated. BPMB had the highest specific surface area of 16.60 m2/g and the smallest pore size of 1.69 nm than other materials. BPB was an amorphous structure, whereas BPZB, BPMB, and BPZMB were crystalline structures presenting their specific metal oxide peaks of ZnO or MgO. They were coarse surfaces and had a spherical shape consisting of C, O, Ca, Cl, and Na. Their main functional groups were O–H, C–H, C=O, C–O, and N–H. The points of zero charge of BPB, BPZB, BPMB, and BPZMB were 5.37, 6.75, 9.87, and 9.43. The cadmium removal efficiencies of BPB, BPZB, BPMB, and BPZMB were 89.18%, 96.62%, 99.59%, and 97.85%, and their q m values were 90.09, 232.56, 454.55, and 303.03 mg/g, respectively. Thus, the metal oxide helped to improve material efficiency, especially MgO. The Freundlich and pseudo-second-order kinetic models were good fit models for describing their adsorption patterns and mechanisms. The increasing temperature affected to decrease their cadmium adsorptions. They could be reused in more than 3 cycles of more than 73% of cadmium adsorption. The electrostatic interaction played an important role in describing their cadmium adsorptions. Therefore, BPBM was a good cadmium adsorbent for application in industrial wastewater treatment since it had a higher performance of cadmium adsorption than other materials.

Two methylene blue (MB) dye adsorbents were synthesized from mangosteen peels modified by magnesium oxide and titanium dioxide called mangosteen peel doped magnesium oxide beads (MMB) and mangosteen peel doped titanium dioxide beads (MTB) to examine which material could greater adsorb MB dye. In addition, several techniques of BET, XRD, FESEM-FIB, EDX, and FT-IR were used for their characterizations. Their MB dye removal efficiencies were investigated by batch experiments, desorption experiments, adsorption isotherms, kinetics, and thermodynamic studies. MTB had a higher specific surface area (15.24 m2/g) and smaller pore size (1.69 nm) than MMB. The results of XRD, FESEM-FIB, EDX, and FT-IR demonstrated the successful additions of magnesium oxide and titanium dioxide into MMB and MTB because they found the specific peaks, characteristic structures, elements, and functional groups of magnesium oxide and titanium dioxide in MMB and MTB. Batch experiments showed they had high MB dye removal efficiencies of more than 97 %, and they could reuse more than three cycles. Freundlich and pseudo-second-order kinetic models were good explanations for their adsorption patterns correlated to chemisorption and their mechanisms to be a chemisorption process. In addition, they were an endothermic process since their MB dye adsorptions increased with increasing temperature.

The generation of oxygen vacancies and Bi-metal on BiVO 4 enhances conductivity, extending both catalytic activity and cyclability in Li–O 2 batteries. [Display omitted] Bismuth Vanadate (BiVO 4) is a promising oxide-based photoanode for electrochemical applications, yet its practical use is constrained by poor charge transport properties, particularly under dark conditions. This study introduces a novel BiVO 4 variant (Bi-BiVO 4 -10) that incorporates abundant oxygen vacancies and in-situ formed Bi metal, significantly enhancing its electrical conductivity and catalytic performance. Bi-BiVO 4 -10 demonstrates superior electrochemical performances compared to conventional BiVO 4 (C-BiVO 4), demonstrated by its most positive half-wave potential with the highest diffusion-limiting current in the oxygen reduction reaction (ORR) and earliest onset potential in the oxygen evolution reaction (OER). Notably, Bi-BiVO 4 -10 is explored for the first time as an electrocatalyst for lithium-oxygen (Li–O 2) cells, showing reduced overcharge (610 mV) in the first cycle and extended cycle life (1050 h), outperforming carbon (320 h) and C-BiVO 4 (450 h) references. The enhancement is attributed to the synergy of oxygen vacancies, Bi metal formation, increased surface area, and improved electrical conductivity, which collectively facilitate Li 2 O 2 growth, enhance charge transport kinetics, and ensure stable cycling. Theoretical calculations reveal enhanced chemical interactions between intermediate molecules and the defect-rich surfaces of Bi-BiVO 4 -10, promoting efficient discharge and charge processes in Li–O 2 batteries. This research highlights the potential of unconventional BiVO 4 -based materials as durable electrocatalysts and for broader electrochemical applications. [ABSTRACT FROM AUTHOR]

• Impacts of LFG impurities and oil additives on deposit formation in engine combustion chamber. • Role of organometallic compounds containing S, Si, Sb, Sn, and P in deposit formation. • Cross-sectional analysis to reveal non-uniform elemental distribution in engine deposits. • Impact of deposit formation in engine combustion chamber on the deterioration of lube oil quality. • Identifying the most effective mechanisms contributing to deposit formation in LFG engine. Combustion chamber deposits adversely affect the operating performance of gas engines. In this study, the elemental composition of deposit samples collected from the inner surface of combustion chambers in gas engines across three different facilities was examined using various methods. The proportional changes in metal oxides along the internal cross-sectional surfaces of the deposits were examined to depict the deposit formation process from beginning to end. Additionally, the study investigated the identification of metals accumulated in the engine oil, their contribution to deposit formation, and the accumulation mechanisms of metal oxide nanoparticles on the engine's interior metal surfaces. The main elements identified in the deposits from the Odayeri and Kömürcüoda facilities were Si, S, and Ca, whereas deposits from the Dilovası facility contained Si and Sb. These major elements, identified by SEM-EDS, were confirmed through XRF analysis. XRD analysis further confirmed the presence of Ca and S as CaSO 4 crystals in the deposits. Ca originates from additives used to increase the total base number of engine oil and control the corrosive effects of landfill gas. It has been determined that silicon accumulates in engine oil over time. An important finding is that metal oxides in the combustion chamber primarily accumulate through impaction, sticking, and thermophoresis mechanisms. [ABSTRACT FROM AUTHOR]

Abstract Background Antimicrobial resistance has emerged as a major global health threat, necessitating the urgent development of new antimicrobials through innovative methods to combat the rising prevalence of resistant microbes. With this view, we developed three novel nanoconjugates using microbial natural pigment for effective application against certain pathogenic microbes. Results A natural red pigment (RP) extracted from the endophyte Monascus ruber and gamma rays were applied to synthesize RP-ZnO, RP-CuO, and RP-MgO nanoconjugates. The synthesized nanoconjugates were characterized by different techniques to study their properties. The antimicrobial potential of these nanoconjugates was evaluated. Moreover, the antibiofilm, protein leakage, growth curve, and UV light irradiation effect of the synthesized nanoconjugates were also studied. Our results confirmed the nano-size, shape, and stability of the prepared conjugates. RP-ZnO, RP-CuO, and RP-MgO nanoconjugates showed broad antimicrobial potential against the tested bacterial and fungal pathogens. Furthermore, the RP-ZnO nanoconjugate possessed the highest activity, followed by the RP-CuO against the tested microbes. The highest % inhibition of biofilm formation by the RP-ZnO nanoconjugate. Membrane leakage of E. coli and S. aureus by RP-ZnO nanoconjugate was more effective than RP-MgO and RP-CuO nanoconjugates. Finally, UV light irradiation intensified the antibiotic action of the three nanoconjugates and RP-ZnO potential was greater than that of the RP-MgO, and RP-CuO nanoconjugates. Conclusion These findings pave the way for exploiting the synthesized nanoconjugates as potential materials in biomedical applications, promoting natural, green, and eco-friendly approaches.

In this study, the results of the investigation of the influence of Al atoms on the structural characteristics of ZnO films obtained by the sol-gel method are presented. It has been determined that the glass substrates consist of subcrystallites with dimensions of 28.6 nm, having cubic unit cells with lattice parameters a = 0.3336 nm, and their surfaces belong to the crystallographic orientation (111). It has been identified that the grown thin ZnO films consist of subcrystallites with dimensions of 39.5 nm, having a wurtzite structure with lattice parameters a = b = 0.3265 nm and c = 0.5212 nm, respectively. It has been determined that at the boundaries of the division of these subcrystallites, polycrystalline regions with sizes of 12.6 nm, 28.3 nm, 30 nm, and 33 nm are formed. Additionally, nanocrystallites with sizes of 56.8 nm self-assemble on the surface areas of the deposited films. The increase in the values of the “c”axis of the hexagonal crystal lattice of ZnO films by 0.0009 nm when doping Al atoms from 1% to 5% is explained by the shift of the main structural line (002) at small angles (Δθ=0.12°). It has been established that nanocrystallites with lattice parameters аn = 0.5791 nm, belonging to the spatial group Fd3m, self-assemble on the surface areas of ZnO:Al films. the curve due to the presence of a monoenergetic level of fast surface states at the heterojunction.

Free of posttransfer, on-surface synthesis (OSS) of single-atomic-layer nanostructures directly on semiconductors holds considerable potential for next-generation devices. However, due to the high diffusion barrier and abundant defects on semiconductor surfaces, extended and well-defined OSS on semiconductors has major difficulty. Furthermore, given semiconductors' limited thermal catalytic activity, initiating high-barrier reactions remains a significant challenge. Herein, using TiO2(011) as a prototype, we present an effective strategy for steering the molecule adsorption and reaction processes on semiconductors, delivering lengthy graphene nanoribbons with extendable widths. By introducing interstitial titanium (Tiint) and oxygen vacancies (Ov), we convert TiO2(011) from a passive supporting template into a metal-like catalytic platform. This regulation shifts electron density and surface dipoles, resulting in tunable catalytic activity together with varied molecule adsorption and diffusion. Cyclodehydrogenation, which is inefficient on pristine TiO2(011), is markedly improved on Tiint/Ov-doped TiO2. Even interribbon cyclodehydrogenation is achieved. The final product's dimensions, quality, and coverage are all controllable. Tiint doping outperforms Ov in producing regular and prolonged products, whereas excessive Tiint compromises molecule landing and coupling. This work demonstrates the crucial role of semiconductor substrates in OSS and advances OSS on semiconductors from an empirical trial-and-error methodology to a systematic and controllable paradigm. [ABSTRACT FROM AUTHOR]

In this study, we explore the synthesis and gas-sensing capabilities of zinc stannate (Zn2SnO4) in three morphologiesspherical nanoparticles, urchins, and octahedronsaiming to investigate the influence of morphology on sensing properties. The fabricated devices exhibit a significant resistance decrease upon exposure to NO2 at room temperature (24 °C), indicating p-type sensing behavior. Among these morphologies, the spherical nanoparticle-based sensor exhibits the highest sensor response of 57% to 6 ppm of NO2, outperforming urchins and octahedrons by approximately 1.2 and 4.1 times, respectively. This superior performance, with response and recovery times of 6.3 s and 224 s, is attributed to enhanced redox reactions from a larger surface area and a higher proportion of oxygen interstitials. The spherical nanoparticle-based sensor also demonstrates exceptional selectivity for NO2 over SO2, CO, NH3, and CH4, with a detection limit of 200 ppb. Furthermore, the sensor exhibits excellent reversibility with only 2% variation across 20 consecutive test cycles and demonstrates remarkable long-term stability, with a performance fluctuation of approximately 2.3% over 63 days without significant degradation. [ABSTRACT FROM AUTHOR]

Metal-organic framework (MOF) derived metal oxide nanostructures hold immense promise as electrodes for energy storage/conversion applications, notably in supercapacitors and urea oxidation. This study explores into optimizing such nanostructures, specifically focusing on a Zr/Ni ratio of 1:1, which has exhibited favorable electrochemical and catalytic performance. Employing thorough characterization methods, including PXRD analysis, we verified the successful synthesis of a ZrO 2 /NiO binary phase (i.e. Zr/Ni) nanostructure via the MOF-derived approach, showcasing its versatility as a catalyst across diverse energy conversion domains. The Zr/Ni nanostructure electrode displayed noteworthy characteristics, boasting a capacity of 432 C/g alongside exceptional cycling stability of 99%, reflecting battery-like electrochemical behavior. Furthermore, in an asymmetric device setup (Zr/Ni//AC), it achieved a notable potential of up to 1.4 V with an impressive power density of 1044.56 W/kg. Additionally, the Zr/Ni nanostructure demonstrated efficient electrocatalytic activity in urea oxidation, evidenced by a maximum current density of 60 mA/cm2. This underscores its viability as a preferred catalyst in energy conversion applications, signaling opportunities for further exploration and advancement in this dynamic field. [Display omitted] • Successful formation of a binary phase of Zr/Ni nanostructure achieved by single step route. • Zr/Ni nanostructure demonstrated a specific capacity of 432C/g. • Zr/Ni//AC device showed ED of 4.08 Wk/g@ 420 W/kg. • Zr/Ni nanostructure exhibits a low onset voltage (1.34 V) in urea oxidation. • Zr/Ni nanostructure shows the highest current density of 60 mA/cm2. [ABSTRACT FROM AUTHOR]

This comprehensive review delves into the burgeoning field of nanotechnology, where the synthesis of nanoparticles (NPs) is strategically tailored to specific applications. Embracing the principles of green chemistry, nanotechnology increasingly utilizes environmentally friendly materials, such as plant extracts or microorganisms, as capping or reducing agents and solvents in the synthesis process. Notably, plant-based synthesis demonstrates enhanced stability and faster rates compared to microorganisms. The synthesized materials exhibit unique properties ranging from antimicrobial and catalytic effects to antioxidant activities and they are finding applications across diverse fields. Green synthesis processes, characterized by mild conditions in terms of temperature and reagents, stand in stark contrast to traditional chemical synthesis methods. This review focuses on the synthesis of various metal and metal oxide NPs, including Ag, Au, Zn, Fe, Mg, Ti, Sn, Cu, Cd, Ni, Co, and Ag NPs and their oxides, using plant extracts and microorganisms. We provide a comprehensive analysis of the advantages, disadvantages, and applications associated with each synthesis method. Additionally, we explore the future prospects of green synthesis and its limitations and challenges, offering insights into its evolving role in nanotechnology. [ABSTRACT FROM AUTHOR]

Polymeric sheets of poly(methyl methacrylate) loaded with organic dye with various amounts of metal oxide nanopowder are promising alternatives to traditional inorganic materials, as they have similar mechanical properties to flexible substrates with relatively high refractive index that can be used in flexible optical/optoelectronic devices. Polymeric sheets of poly(methyl methacrylate) loaded with boron subphthalocyanine chloride with various amounts of cerium(IV)-zirconium(IV) oxide nanopowder were fabricated. Fourier transform infrared spectroscopy and X-ray diffraction techniques were used to examine and analyse the structure of the fabricated polymer sheets. Introducing organic dye and nanofiller in the polymer molecular chains matrix does not change the infrared characteristic transmission peaks. The X-ray diffraction spectra of the polymeric sheets have an amorphous nature. Characterized by spectroscopic measurements (fluorescence, transmittance, and reflectance), the optical properties such as the optical energy gap, emission bands, and refractive index of the fabricated polymer sheets were explored. By controlling the concentration of boron subphthalocyanine chloride and cerium(IV)-zirconium(IV) oxide nanopowder, energy gaps and the refractive indexes of the fabricated polymer sheets can be controlled. The poly(methyl methacrylate) loaded with boron subphthalocyanine chloride with 20 mg cerium(IV)-zirconium(IV) oxide nanopowder showed optical energy gap transitions at 4.79, 2.66 eV, and 2.08 eV, it has the highest PL intensity with a strong emission band at 413 nm, and also it has the highest refractive index. Finally, the obtained experimental results showed that the prepared polymer systems can be considered promising flexible polymer sheets for optics, and photonics devices. [ABSTRACT FROM AUTHOR]

This study presents the synthesis of a multicomponent metal oxide electrocatalyst that increases the activity of the oxygen evolution reaction (OER). We synthesized transition metal oxides (MnOx, FeOx, CoOx, and NiOx) with MoO3 heterostructures through a solid-state reaction approach at low cost. In comparison to the other compositions, CoOx garnered higher attention and demonstrated superior performance on account of its large surface area and varied crystal facets. The MnOx-MoO3, FeOx-MoO3, CoOx-MoO3, and NiOx-MoO3 compositions attained an overpotential of 390 mV, 350 mV, 310 mV, and 340 mV, respectively, at a current density of 10 mA cm−2 in alkaline solution. The performance of OER was enhanced in CoOx-MoO3 at 10 mA cm−2, while FeOx-MoO3 exhibited a lower current density at 100 mA cm−2 than other metal oxides. The CoOx-MoO3 material exhibited a favorable crystal interface transition due to the presence of MoO3 oxide. For the first time, we report on the MoO3-to-(MnOx, FeOx, CoOx, and NiOx) interface crystal transition and the active surface area for OER catalytic activity in water-splitting processes. This investigation intends to develop an electrocatalyst that is capable of producing hydrogen with the use of heterostructure metal oxides. [ABSTRACT FROM AUTHOR]