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In this study, a C–CoFe 2 O 4 composite is proposed for reduction in an induction heating reactor with a continuous argon flow. An impressive conversion efficiency of 87% is achieved at a maximum temperature of 325 °C in just 8 min without the need for vacuum. The impact of the molar ratio of metal oxide to reducing agent (acetylacetone) is also examined. Results indicate that a 1:1 ratio favours the reduction towards cobalt and iron monoxides, while a 1:3 ratio yields a 31% metal phase. The highest conversion (87%) is seen with a 1:17 ratio, indicating the need for excess reducing agent for effective conversion of CoFe 2 O 4 oxide. The molar ratio influences the induction heating temperature, with the 1:17 ratio having a lower temperature of 325 °C compared to 450 °C for other ratios. These operating temperatures (≤450 °C) are significantly lower than those reported in the literature for carbothermal reduction in an induction reactor (>1700 °C), which often requires vacuum and very high temperatures for high conversion efficiency. The proposed process offers advantages such as high conversion efficiency, fast processing, and simpler operational conditions. Additionally, the metallic phases produced are utilized for H 2 production in thermochemical water splitting, showcasing these materials potential for energy generation applications. [Display omitted] • Induction heated C–CoFe 2 O 4 achieves 87 % metal oxide-to-metal conversion at 325 °C. • This method results in a faster and more efficient reduction process at lower T. • Reduction efficiency is influenced by molar ratio of metal oxide to reducing agent. • The metallic phase is applied for thermochemical H 2 production (3.905 mmol H 2 g−1). [ABSTRACT FROM AUTHOR]

Zirconia has important application prospects in the field of ceramics. However, during a high-temperature heating process, pure zirconia will undergo martensite transformation, which seriously affects its service performance. Metal oxides, such as Y 2 O 3 –CeO 2 doping ZrO 2, effectively improve the toughness and fire resistance of the material. Thus, the drying of Y 2 O 3 –CeO 2 co-doped ZrO 2 powder is an essential step before practical application. The study employs contemporary microwave drying techniques. The results of the experiment show that the average microwave drying rate increases with an increase in mass, water content, and microwave heating power. When the initial mass was 30 g, the initial moisture content was 12 %, microwave power was 720 W, and the drying rate was the fastest. We used four dynamic models: Modified Page, Quadratic, Wang and Singh, and Page to fit the experiment data. The best model was Modified Page, which describes the kinetic process most accurately. Fick's second law describes how, in the drying process, when microwave power is 720 W, initial mass is 15 g and initial water content is 8 %, the effective diffusion coefficient is 5.25 × 10−16 m2/s. Fourier Transforms of the infrared spectrum of the samples before and after drying were analyzed, the intensity of the O–H absorption peak located at 3442.03 cm/s, and O–H–O absorption peak located at 1594.48 cm/s. Both decreased significantly after drying. To discuss the relationship between the microwave power and the diffusion coefficient, the activating energy of microwave heating was 32.01 W/g. The experimental results show high heating efficiency and selective heating of the microwave method. This study provides a theoretical basis and research data for microwave drying of Y 2 O 3 /CeO 2 co-doped ZrO 2 powder in industry. [ABSTRACT FROM AUTHOR]

Atom-thin SnO 2 (a-SnO 2) shows promising potential for applications in gas sensors. However, its high working temperature can cause agglomeration, leading to a decrease in the specific surface area and resulting in performance deterioration of the sensors. In this study, g-C 3 N 4 was utilized as a thermal support to address this issue and improve the gas-sensing properties of a-SnO 2. When a-SnO 2 was grown with 10 wt% g-C 3 N 4 dispersed evenly in ethylenediamine, the gas-sensing performance of the composite improved significantly, including the response value (R a / R g = 8.8–10 ppm HCHO), fast response (τ res = 1.6 s), ultralow detection limit (0.1 ppm), long-term stability and humidity-resistance properties. This work not only introduces a method to utilize a thermal support for atom-thin metal oxides, enhancing their stability at high working temperatures but also investigates the underlying mechanism. This study provides valuable insights into the application of ultrathin metal oxides. Additionally, it facilitates the development of a portable smart system for detecting HCHO contamination in practical settings. [ABSTRACT FROM AUTHOR]

Thermodynamic modeling of metal oxide reduction is crucial for optimizing chemical processes and materials in systems dependent on off-stoichiometric reduction/re-oxidation cycling. Two prevalent methods for extracting reduction thermodynamics from thermogravimetric data are linearized van 't Hoff (VH) analysis and the compound energy formalism (CEF). This work evaluates the accuracy of these methods by constructing invertible ground truth thermodynamic models, generating hypothetical thermogravimetric data, and determining the reduction thermodynamic using both VH and CEF methods. Our findings reveal that the VH method produces absolute errors 3–5 times higher than the CEF in kJ/mol O or J/mol O K for enthalpy and entropy of reduction, respectively. In contrast, the CrossFit CEF (CF-CEF) method yields errors often less than 10 kJ/mol O or J/mol O K. Moreover, the CF-CEF method provides models based on mole fraction, temperature, and extent of reduction, while a typical VH analysis provides thermodynamics of only the specific compositions measured. Although simple to implement, the VH method suffers from significant, non-systematic errors due to entropy/enthalpy compensation and defect modeling. Consequently, we recommend the more complex but robust, CF-CEF method for extracting redox thermodynamics from thermogravimetric measurements. [ABSTRACT FROM AUTHOR]

Herein in this study, a new nanosorbent consisted of perovskite cobalt–nickel oxide Co0.5Ni0.5O and perovskite cobalt–molybdenum oxide Co2Mo3O8, copper oxide CuO, and zinc oxide ZnO, has been synthesized. The structural and morphological properties of the nanosorbent were established by using FT-IR, PXRD, TGA, HR-TEM, SEM, and EDX. The nanosorbent was implemented to adsorb 60Co and 152+154Eu radioactive isotopes under diverse conditions using different pH values, contact times, radioactive nuclides concentrations, and temperatures. The highest adsorption removal for both radionuclides was obtained at pH 6.0 as 83.65 and 122.50 mg/g for 60Co(II), and 152+154Eu(III), respectively. The adsorption models for 60Co(II) were fitted with Temkin only, on the other hand, the adsorption of 152+154Eu(III) was fitted with four adsorption models. The kinetics for 60Co(II) were fitted with the Pseudo first order (PFO), Pseudo second order (PSO), and Intraparticle models on the other hand 152+154Eu(III) were found to agree with the Pseudo first order (PFO) and intraparticle models. [ABSTRACT FROM AUTHOR]

This study focuses on Pb2+ and As(V) adsorption on mineral heterostructures based on a mixture of Si, Fe, and Ti oxides (MOHs). Various techniques were performed to analyze the morphological and structural properties of the synthesized metal oxide samples. In addition to the experimental optimization of the parameters determined by the response surface method (RSM), the effects of pH, adsorbent dosage, temperature, and contact duration on the batch and column system adsorption efficiency of single-component and simultaneous lead and arsenate removal were tested. The pseudo-second-order kinetic model and Weber–Morris model were more relevant to the adsorption on the metal(loid)s. The adsorption of Pb2+ was related to the Langmuir isotherm model, while the adsorption of As(V) was fitted to the Freundlich isotherm model. The thermodynamic parameters indicate the spontaneity of the adsorption process with a low endothermic character. The MOHs were more effective in removing Pb2+ and As(V) in the multi-component system (87.7 and 46.1%, respectively) than in the single-component system (56.3 and 23.4%, respectively). This study demonstrates that mineral heterostructures can be effectively used to remove cations and anions from water systems, and due to their fast kinetics, they can be applied to the needs of rapid interventions after pollution. [ABSTRACT FROM AUTHOR]

Quantifying methane emissions is essential for meeting near-term climate goals and is typically carried out using methane concentrations measured downwind of the source. One major source of methane that is important to observe and promptly remediate is fugitive emissions from oil and gas production sites but installing methane sensors at the thousands of sites within a production basin is expensive. In recent years, relatively inexpensive metal oxide sensors have been used to measure methane concentrations at production sites. Current methods used to calibrate metal oxide sensors have been shown to have significant shortcomings, resulting in limited confidence in methane concentrations generated by these sensors. To address this, we investigate using machine learning (ML) to generate a model that converts metal oxide sensor output to methane mixing ratios. To generate test data, two metal oxide sensors, TGS2600 and TGS2611, were collocated with a trace methane analyzer downwind of controlled methane releases. Over the duration of the measurements, the trace gas analyzer's average methane mixing ratio was 2.40 ppm with a maximum of 147.6 ppm. The average calculated methane mixing ratios for the TGS2600 and TGS2611 using the ML algorithm were 2.42 ppm and 2.40 ppm, with maximum values of 117.5 ppm and 106.3 ppm, respectively. A comparison of histograms generated using the analyzer and metal oxide sensors mixing ratios shows overlap coefficients of 0.95 and 0.94 for the TGS2600 and TGS2611, respectively. Overall, our results showed there was a good agreement between the ML-derived metal oxide sensors' mixing ratios and those generated using the more accurate trace gas analyzer. This suggests that the response of lower-cost sensors calibrated using ML could be used to generate mixing ratios with precision and accuracy comparable to higher priced trace methane analyzers. This would improve confidence in low-cost sensors' response, reduce the cost of sensor deployment, and allow for timely and accurate tracking of methane emissions. [ABSTRACT FROM AUTHOR]

In this work, the highly efficient hydrogenation of guaiacol catalyzed by ruthenium supported on Al2O3-TiO2 (Ru/Al2Ti1) at very mild conditions was carried out. At temperatures as low as 25 °C and 2 MPa H2, about 60% of guaiacol could be converted to 2-methoxycyclohexanol (MCH) with a selectivity as high as 94% on the Ru/Al2Ti1 catalyst with an appropriate hydrogen pressure. At temperatures above 50 °C, almost all of the guaiacol could be converted with the catalyst of Ru/Al2Ti1, mainly into hydrogenated products such as MCH. The surprisingly efficient hydrogenation of guaiacol at low temperatures was most likely due to the ability of Ru particles loaded on the specific complex metal oxide carriers, particularly the reduction of the edge effect of Ru, to activate phenyl and hydrogen and reduce the competition of the dimethoxy process. These findings about the high activity of the Ru/Al2Ti1 catalyst at nearly room temperature may be helpful to upgrading the industrial process of the pyrolysis bio-oils. [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]

This paper showcases the development of CuO nanoparticles (CuO NPs) deocrated on the surface of carbon nanotubes (CNTs) in polymer nanofiber structure. Both pulsed laser ablation and electrospinning were used to form decorated CNTs electrospun nanofibrous membrane. These technologies combine the decorated CNTs with electrospinning to create multifunctional membranes from polyurethane (PU) in a straightforward and cost-efficient manner. Different techniques were used to confirm the results. Simultaneously, we observed the morphological features and the particle size of the decorated CuO using scanning and transmission electron microscopy (SEM and TEM) with energy-dispersive X-ray spectroscopy (EDX). XRD analysis revealed sharp diffraction peaks, indicating the high crystalline structure of CuO NPs grown alongside nanotubes. Additionally, the presence of PU in the diffractogram showed minimal difference in the peak strength of the polyurethane matrix. FT-IR analysis also showed unique peaks that confirmed the substitution of graphite structure of CNTs, which shows that the successful decoration of metal oxide. In terms of catalytic performance, the produced samples demonstrated high efficiency in completing the reduction of 4-nitrophenol, particularly when CuO nanoparticles adorned the outer surface of CNTs in the membrane structure. This confirms the potential of using CuO/CNTs/PU nanofibrous membrane in significant quantities to enhance efficiency against hazardous compounds. [ABSTRACT FROM AUTHOR]

Mixed metal oxide (MMO) nanoparticles (NPs) are hybrids consisting of two or more nanoscale metal oxides. Advantages of MMO NPs over single metal oxides include improved catalytic activity, enhanced electrical and magnetic properties, and increased thermal stability due to the synergy of the different oxide components. This study presents a novel fabrication route for TiO2‐CeO2 NPs enriched with oxygen vacancies using a Haberland‐type gas aggregation cluster source. The NPs, deposited from different segmented Ti/Ce targets under varying O2 addition, were examined with respect to final composition, morphology, and Ti, Ce surface oxidation states. Particle formation mechanisms are proposed for the observed morphologies. Additionally, available O2 during deposition and its impact on the formation of defective sites were investigated. Defective sites in TiO2‐CeO2 NPs were analyzed using transfer to X‐ray photoelectron spectroscopy and transmission electron microscopy without contact to ambient oxygen. The incorporation of Ce to the target exhibits synergistic effects on the synthesis process. Segmented Ti/Ce targets enable the deposition of a broad range of mixed oxide NPs with diverse compositions and morphologies at considerably enhanced deposition rates, which is vital for practical applications. The presented fabrication approach is expected to be applicable for a broad variety of MMO NPs. [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]

A strategic option for the production of H2 from renewable resources is use of the ethanol steam reforming reaction. Catalysts based on nickel have been widely investigated for this reaction, offering the advantages of low cost and high activity. However, a difficulty is that nickel may be strongly deactivated by coke formation. Perovskite-type mixed oxides are promising precursors for nickel-based catalysts, since their reduction leads to the formation of highly dispersed metal particles that can mitigate carbon deposition. However, high calcination temperatures are required for perovskite structure formation, resulting in low surface areas and limiting the effectiveness of this method. In order to address this difficulty, the present work proposes a novel strategy whereby the perovskite-type oxide LaNiO3 is supported on SBA-15. Characterization of the catalysts was performed using XRF, XRD, SEM, TPR, TEM, BET, H2-TPD, and TGA techniques. Their performances were then evaluated in catalysis of the ethanol steam reforming reaction to produce hydrogen. Calcination at 750 °C resulted in formation of highly dispersed perovskite on a support that presented high specific surface area. The catalyst obtained from reduced LaNiO3/SBA-15 with 33 wt% perovskite was the most active in the reaction. Analyses using TGA and SEM showed the formation of carbon mainly over Ni catalysts obtained from bulk LaNiO3 perovskite, while supporting LaNiO3 on SBA-15 led to lower deposition of carbon. The superior performance of this material in catalysis could be attributed to the dispersion of the perovskite on SBA-15, resulting in smaller size of the Ni metal particles formed during the reduction, compared to the catalyst derived from bulk perovskite. This promising method could be used in the production of a wide range of other catalysts. [ABSTRACT FROM AUTHOR]

The use of metal oxide nanoparticles (NPs) in skincare products has significantly increased human skin exposure, raising safety concerns. Whilst NP's ability to penetrate healthy skin is minimal, studies have demonstrated that metal oxide NPs can induce toxicity in keratinocytes through direct contact. Moreover, NP's effect on common skin disorders like psoriasis, where barrier impairments and underlying inflammation could potentially increase NP penetration and worsen nanotoxicity is largely unstudied. In this paper, we investigated whether psoriasis-like human keratinocytes (Pso HKs) would exhibit heightened toxic responses to titanium dioxide (TiO2), zinc oxide (ZnO), and/or silica (SiO2) NPs compared to healthy HKs. Cells were exposed to each NP at concentrations ranging between 0.5 and 500 µg/ml for 6, 24, and 48 h. Amongst the metal oxide NPs, ZnO NPs produced the most pronounced toxic effects in both cell types, affecting cell viability, inducing oxidative stress, and activating the inflammasome pathway. Notably, only in ZnO NPs-treated Pso HKs, trappin-2/pre-elafin was cleaved intracellularly through a non-canonical process. In addition, tissue remodelling-related cytokines were upregulated in ZnO NP-treated Pso HKs. The full impact of the observed outcomes on psoriatic symptoms will need further evaluation. Nonetheless, our findings indicate the importance of understanding the sub-lethal impacts of NP exposures on keratinocytes, even though direct exposure may be low, particularly in the context of skin disorders where repeated and long-term exposures are anticipated. [ABSTRACT FROM AUTHOR]

[Display omitted] • The catalytic ozonation performances for seven CeO 2 catalysts with different morphologies and exposed facets are disclosed. • CeO 2 nanorods with (1 1 0) and (1 0 0) facets exposed show the best performance. • A linear relationship between Frenkel-type OV density and O 3 decomposition rate is revealed regardless of morphology and exposed facet. • DFT calculation and experimental data reveal OV boosts O 3 activation on both the Ce and hydroxyl sites of CeO 2. Morphology and facet effects of metal oxides in heterogeneous catalytic ozonation (HCO) are attracting increasing interests. In this paper, the different HCO performances for degradation and mineralization of phenol of seven ceria (CeO 2) catalysts, including four with different morphologies (nanorod, nanocube, nanooctahedron and nanopolyhedron) and three with the same nanorod morphology but different exposed facets, are comparatively studied. CeO 2 nanorods with (1 1 0) and (1 0 0) facets exposed show the best performance, much better than that of single ozonation, while CeO 2 nanocubes and nanooctahedra show performances close to single ozonation. The underlying reason for their different HCO performances is revealed using various experimental and density functional theory (DFT) calculation results and the possible catalytic reaction mechanism is proposed. The oxygen vacancy (OV) is found to be pivotal for the HCO performance of the different CeO 2 catalysts regardless of their morphology or exposed facet. A linear correlation is discerned between the rate of catalytic decomposition of dissolved ozone (O 3) and the density of Frenkel-type OV. DFT calculations and in-situ spectroscopic studies ascertain that the existence of OV can boost O 3 activation on both the hydroxyl (OH) and Ce sites of CeO 2. Conversely, various facets without OV exhibit similar O 3 adsorption energies. The OH group plays an important role in activating O 3 to produce hydroxyl radical (∙OH) for improved mineralization. This work may offer valuable insights for designing Facet- and OV-regulated catalysts in HCO for the abatement of refractory organic pollutants. [ABSTRACT FROM AUTHOR]

Rapid industrialization and increasing electricity demand have highlighted the urgency to reduce energy losses in power generation, accounting for over 60% of global inefficiency. Thermoelectric materials are pivotal for improving energy conversion in high-performance systems. We synthesized La5SrCu6-xFexO15-δ samples via solidphase reaction to study elemental substitution effects on thermoelectric properties. The performance was evaluated by the dimensionless figure of merit ZT = TS² σ/κ, integrating the Seebeck coefficient (S), electrical conductivity (σ), and thermal conductivity (κ). Our results show Fe substitution significantly changes structural, electronic, magnetic, and thermoelectric properties of La5SrCu6O15-δ compound. Fe dopants improve ZT, particularly at higher temperatures, highlighting the potential application on material properties. [ABSTRACT FROM AUTHOR]

Thin‐film tandem photovoltaic (PV) technology has emerged as a promising avenue to enhance power conversion efficiency beyond the radiative efficiency limit of single‐junction devices. Combining a tunable wide‐bandgap perovskite cell with a commercially established narrow‐bandgap cadmium selenium telluride (CdSeTe) cell in a comparatively easy‐to‐fabricate four‐terminal (4‐T) arrangement is a great step in that direction. Herein, the impact of the transparent back contact and the perovskite absorber bandgap on the performance of 4‐T perovskite–CdSeTe tandem solar cells is investigated. 4‐T perovskite–CdSeTe tandem device architecture with ≈25% efficiency is demonstrated and a feasible pathway is shown to improve the tandem efficiency to more than 30%. The results show that the integration of CdSeTe with perovskite in 4‐T tandem PV configurations represents a significant advancement toward achieving higher efficiency and low‐cost tandem PVs. [ABSTRACT FROM AUTHOR]

The zinc oxide nanoparticles (ZnO NPs) is one of the most extensively utilized metal oxide nanoparticles in biomedicine, human food, cosmetics and livestock farming. However, growing evidence suggests that there is a potential risk for humans and animals because of the accumulation of ZnO NPs in cells, which leads to cell death through several different pathways. Nevertheless, the effects of ZnO NPs on porcine granulosa cells (PGCs) and how ZnO NPs regulate the follicular cells are unknown. In this study, we aimed to elucidate the role of ZnO NPs in the porcine ovary by using PGCs. Firstly, we identified the characterization of ZnO NPs used in this study and the results showed that the size of ZnO NPs was 29.0 nm. The results also demonstrated that ZnO NPs impaired cell viability and decreased steroid hormone secretion in PGCs. In addition, ZnO NPs induced reactive oxygen species (ROS) production, leading to oxidative stress of PGCs. Meanwhile, ZnO NPs also triggered autophagy in PGCs by increasing the ratio of LC3-II/LC3-I, along with the expression of SQSTM1 and ATG7. Finally, the results from N-acetylcysteine (NAC) addition suggested that ZnO NPs promoted autophagy through the enhancement of ROS production. In summary, this study demonstrates that ZnO NPs impair the viability and function of PGCs through autophagy, which is regulated by ROS production. [ABSTRACT FROM AUTHOR]

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The use of conductive and corrosion-resistant protective layers represents a key strategy for improving the durability of light absorber materials in photoelectrochemical water splitting. For high performance photoanodes such as Si, GaAs, and GaP, amorphous TiO2 protective overlayers, deposited by atomic layer deposition, are conductive for holes via a defect band in the TiO2. However, when coated on simply prepared, low-cost photoanodes such as metal oxides, no charge transfer is observed through amorphous TiO2. Here, we report a hybrid polyethyleneimine/TiO2 layer that facilitates hole transfer from model oxides BiVO4 and Fe2O3, enabling access to a broader scope of available materials for practical water oxidation. A thin polyethyleneimine layer between the light absorber and the hybrid polyethyleneimine/TiO2 acts as a hole-selective interface, improving the optoelectronic properties of the photoanode devices. These polyethyleneimine/TiO2 modified photoanodes exhibit high photostability for solar water oxidation over 400 h. This study presents a hybrid polyethyleneimine/TiO2 protective layer as a low-cost photoanode for solar water oxidation. The hybrid layer facilitates hole transfer from the photoanode and results in high photostability over 400 hours. [ABSTRACT FROM AUTHOR]

Tin-based perovskite solar cells have garnered attention for their biocompatibility, narrow bandgap, and long thermal carrier lifetime. However, nip-type tin-based perovskite solar cells have underperformed largely due to the indiscriminate use of metal oxide electron transport layers originally designed for nip-type lead-based perovskite solar cells. Here, we reveal that this underperformance is caused by oxygen vacancies and deeper energy levels in metal oxide. To address these issues, we propose a metal chalcogenide electron transport layer, specifically Sn(S0.92Se0.08)2, which circumvents the oxygen molecules desorption and impedes the Sn2+ oxidation. As a result, tin-based perovskite solar cells with Sn(S0.92Se0.08)2 demonstrate a VOC increase from 0.48 – 0.73 V and a power conversion efficiency boost from 6.98 – 11.78%. Additionally, these cells exhibit improved stability, retaining over 95% of their initial efficiency after 1632 h. Our findings showcase metal chalcogenides as promising candidates for future nip-type tin-based perovskite solar cell applications. nip-Type tin-based perovskite solar cells have underperformed largely due to the metal oxide electron transport layers originally designed for lead-based devices. Here, authors employ metal chalcogenide as the electron transport layer, achieving enhanced efficiency up to 11.78% for stable devices. [ABSTRACT FROM AUTHOR]

There are several advantages to the MIG (Metal Inert Gas) process, which explains its increased use in various welding sectors, such as automotive, marine, and construction. A variant of the MIG process, where the same equipment is employed except for the deposition of a thin layer of flux before the welding operation, is the AMIG (Activated Metal Inert Gas) technique. This study focuses on investigating the impact of physical properties of individual metallic oxide fluxes for 304L stainless steel welding joint morphology and to what extent it can help determine a relationship among weld depth penetration, the aspect ratio, and the input physical properties of the oxides. Five types of oxides, TiO2, SiO2, Fe2O3, Cr2O3, and Mn2O3, are tested on butt joint design without preparation of the edges. A robust algorithm based on the particle swarm optimization (PSO) technique is applied to optimally tune the models' parameters, such as the quadratic error between the actual outputs (depth and aspect ratio), and the error estimated by the models' outputs is minimized. The results showed that the proposed PSO model is first and foremost robust against uncertainties in measurement devices and modeling errors, and second, that it is capable of accurately representing and quantifying the weld depth penetration and the weld aspect ratio to the oxides' thermal properties. [ABSTRACT FROM AUTHOR]

With the increasing market demands for wearable and portable electronic devices, binary metal oxides (BMOs) with a remarkable capacity and good structure stability have been considered as a promising candidate for fabricating coplanar micro-supercapacitors (CMSCs), serving as the power source. However, the current fabrication methods for BMO microelectrodes are complex, which greatly hinder their further development and application in BMO CMSCs. Herein, the one-step fabrication of 2.5D CuMoOx-based CMSCs (CuMoCMSCs) has been realized by numerically controlled electric discharge machining (NCEDM) for the first time. In addition, the controllable capacity of CuMoCMSCs has been achieved by adjusting the NCEDM-machining voltage. The CuMoCMSCs machined by a machining voltage of 60 V (CuMoCMSCs60) showed the best performance. The fabricated CuMoCMSCs60 with binary metal oxides could operate at an ultra-high scanning rate of 10 V s−1, and gained a capacity of 40.3 mF cm−2 (1.1 mA cm−2), which is more than 4 times higher than that of MoOx-based CMSCs (MoCMSCs60) with a single metal oxide. This is because CuMoOx BMOs materials overcome the poor electroconductivity problem of the MoOx single metal oxide. This one-step and numerically controlled fabrication technique developed in this research opens a new vision for preparing BMO materials, BMO microelectrodes, and BMO microdevices in an environmental, automatic, and intelligent way. [ABSTRACT FROM AUTHOR]

Nowadays, increasing emissions of hazardous chemicals cause serious environmental pollution. The advanced oxidation processes (AOPs), which produce numbers of reactive oxygen species (ROS), are one of the most widely used technologies for degrading refractory pollutants in aqueous phase. Among these, Fenton reaction including both homogeneous and heterogeneous processes, has received increasing attention for water treatment. In this review, various nanomaterials with different size such as nanocrystals, nanoparticles (e.g., iron-based minerals, bimetallic oxides, zero-valent iron, quantum dots) and metal-based single atom catalysts (SACs) applied in homogeneous and heterogeneous Fenton reactions, as well as the corresponding catalytic mechanisms will be systematically summarized. Several factors including the morphology, chemical composition, geometric/electronic structures influence the catalytical behavior simultaneously. Here, the recent research advancement including the advantages and further challenges in homogeneous and heterogeneous Fenton system will be introduced in detail. Furthermore, developments for different nanomaterials, from nanocrystals, nanoparticles (minerals, bimetallic oxides represented by Fe-based catalysts, and nanosized zero valent iron materials) to SACs will be discussed. Some representative catalysts for Fenton reaction and their applications will be presented. In addition, commonly-used supports (e.g., graphene oxide, g-C3N4, and carbon nanotubes) and metal-organic frameworks (MOFs)/derivatives and metal-support interaction for improving Fenton-like performance will be introduced. Finally, different types of catalysts for Fenton reaction are compared and their practical application and operational costs are summarized. [ABSTRACT FROM AUTHOR]

Perpendicular magnetic anisotropy (PMA) induced at the interface of the metallic magnetic layer/oxide layer plays a major role in scaling of state-of-the-art spin-transfer-torque magnetoresistive random access memory. The realization of PMA requires the development of mature interface manipulation techniques as well as materials constituting the interface. Herein, we report large PMA using stacks developed with an ultrathin (∼0.7 nm) Fe/rock-salt CrO(001) interface via an oxygen-driven diffusion process. The stacks were prepared by sputter-deposition and post-annealing of the Cr buffer/ultrathin Fe/MgO structure. Significant oxidation of the Fe layer and Cr diffusion into the MgO layer occurred during the deposition. After post-annealing, the oxidized Fe layer was reduced to form an Fe/rock-salt-type Cr-monoxide structure due to chemical layer exchange. The lattice-matched Fe/CrO interface with a large interfacial PMA energy of 1.55 mJ/m2 was confirmed after annealing at 500 °C. X-ray absorption spectroscopy measurements revealed that the post-annealing promoted the redox reaction from the Fe oxide to the metallic Fe and the formation of the CrO. The observed PMA indicates that the oxygen-driven diffusion process by annealing resulted in the well-controlled Fe/CrO interface. The demonstrated diffusion process provides a new chemical route to fabricate artificial, well-controlled PMA interfaces, even containing metastable materials, beyond the conventional sequential layer stacking for the development of spintronic devices. [ABSTRACT FROM AUTHOR]

Super-capacitor is a well-competing energy storage system that involves fast-charging capability, a long-life cycle, stability, and good retention. Here, we examine solution combustion-derived AMn2O4 (A = Ni, Cu, Co, Zn) nanoparticles as a good supercapacitor electrode material. The electrochemical performance in a 2 M aqueous KOH electrolyte was investigated to find out the best working electrode with excellent activity. Out of all possibilities tested, NiMn2O4 delivered the utmost specific capacitance of 448.82 F g−1 at 50 mVs−1. galvanostatic charge–discharge studies also confirmed that NiMn2O4 had a higher specific capacitance of 598.61 F g−1 at 0.5 A g−1 with energy and power density of 182.31 Wh/kg and 0.20 kW/kg, respectively. Furthermore, NiMn2O4 after 5000 cycles showed excellent long-term cyclic stability, maintaining an impressive retention capability of 96.68%. The results demonstrated that NiMn2O4 electrode had good stability and electrochemical reversibility, as well as specific capacity dependent on the type of transitional metal oxides. [ABSTRACT FROM AUTHOR]

Spinel metal oxides are extensively studied for supercapacitors (SCs) in alkaline electrolytes, where charge storage capacity is limited by surface site availability due to surface reconstruction forming metal hydroxides/oxyhydroxides. The use of an acidic medium, which can boost the charge storage capacity of spinel oxides offering an additional channel of intercalation‐deintercalation of protons, is underexplored. Moreover, the impact of chemical compositions and the cationic distributions is crucial on the electrocatalysis performance of spinel oxides, however, such a correlation is first time reported for charge storage properties of spinel ferrite NiFe2O4 nanoparticles (NFO NPs). Besides, a low‐cost and scalable synthesis of NFO NPs involving the thermal decomposition of Ni‐Fe glycolate, followed by controlled air‐calcination is reported. Thus crafted NFO NPs‐based device shows impressive specific capacitance (2112 F g−1 at 10 A g−1) in half‐cell configuration. A flexible all‐solid‐state asymmetric device (full‐cell) configuration depicts impressive energy density (20.7 Wh kg−1), power density (4000 W kg−1), gravimetric capacitance (140 F g−1 at 2 A g−1), and retention of its performance (≈75% after 10,000 charging/discharging cycles). The results depict a new insight toward the tuning of electronic and charge storage properties in NFO, which otherwise are predominately attributed to only the crystallite size and morphological effects. [ABSTRACT FROM AUTHOR]

Heterogeneous catalytic ozonation (HCO) emerges as a promising chemical industrial wastewater treatment solution, offering enhanced ozone utilization and reduced secondary pollutants. However, challenges in scaling HCO arise from a limited understanding of the catalytic mechanisms of metal oxides, particularly in generating active ozone sites. Here, we demonstrated the improvement of catalytic ozonation efficiency by enhancing the covalent bonding between FeO in Fe/Co spinel oxides. This alteration exploits the stronger electron‐donating capacity of Fe (II), enhancing FeOM bonds and electron enrichment at iron sites, leading to a significant reduction in the activation energy for ozone. Pilot experiments demonstrated a 75.3% COD removal efficiency and a threefold increase in ozone utilization efficiency compared to pure ozone system for chemical industrial wastewater treatment. This study not only advances our understanding of spinel oxides in ozone catalysis but also opens new avenues for practical HCO applications in water treatment. [ABSTRACT FROM AUTHOR]

This work is devoted to studying and manufacturing a highly sensitive nonenzymatic glucose biosensing system of metal oxides via the sol–gel technique. The X‐ray diffraction patterns of all the prepared samples confirm that the samples present hexagonal crystal lattice structures of ZnO and Ag–ZnO nanoparticles. Ultraviolet (UV) analysis of all the samples is carried out to evaluate the absorption of silver in the UV region for electrical and chronoamperometric analysis. The transmittance of all the samples is observed, and the maximum transmittance is 11% for 4% AgZnO. Fourier transform infrared spectroscopy reveal the functional group stretching and vibration of the particles at different wavelength ranges. Scanning electron microsocpy analysis reveals the grain size and morphology of the samples, which decrease with increasing doping agent. Chronoamperometric analysis of all the samples reveals that the value increases with time for the 4% doped sample. The sensing response is also observed and is enhanced with increasing temperature for the 4% doped sample. The sensing response of the samples coated with carbon fiber electrodes is assessed from −0.2 to +0.5 V at a scan rate of 50 mV s−1. [ABSTRACT FROM AUTHOR]

As nanotechnology becomes more important and prevalent, a new reproducible and production-stable synthesis method is needed to meet the demand for the industrial production of nanomaterials. Supercritical fluid (SCF) synthesis is an essential method for the synthesis of metal and metal oxide nanoparticles owing to its fast reaction rate, uniform particle size distribution, high conversion rate, and environmentally friendly nature. This study systematically investigated the crystal nucleation mechanism of metal and metal oxide nanoparticles during synthesis. The effects of reaction material parameters and process parameters on the particle size distribution and conversion rate of nanoproducts were analyzed. Next, the SCF process and the improvement of its core components (mixer and reactor) were studied. Finally, the improvements made to the SCF process were evaluated and future investigation directions are proposed. By presenting a comprehensive overview of SCF technology, this study aims to contribute to the development of a reliable and effective method for the industrial production of nanomaterials. [ABSTRACT FROM AUTHOR]

Several studies have reported about different hydrogen production and storage materials. The use of metal oxides, particularly iron oxides, as hydrogen storage materials offers a promising solution to bridge hydrogen production and utilization. The iron‐steam process, dating back to the 18th century, leverages iron's ability to bind oxygen from steam, producing hydrogen and iron oxides. This study revisits the iron/iron oxide system for its dual application as a hydrogen storage medium and as an energy carrier in systems like fuel cells. When integrated with high‐temperature electrolysis and fuel cells, this system can efficiently operate between 600 and 1000 °C. The key to long‐term performance lies in understanding the formation and stability of oxygen‐binding structures. Stabilizing the iron oxides for cycling procedures with other metal oxides like Al2O3, SiO2, and CaO is inevitable. Ceramic‐stabilized iron oxide pellets offer advantages including high cycling capability, efficient charge/discharge operations, and potential syngas production. They are particularly suitable for heavy goods vehicles, short‐term storage, and large‐scale industrial applications. Critical process parameters for the iron oxide material and process design must be investigated if an accurate assessment of the performance of this hydrogen storage concept is to be transferred into efficient practice. [ABSTRACT FROM AUTHOR]

Engineering sites of supported metal catalysts is essential to enhancing activity and selectivity. Such enhancement is typically achieved by particle size modification, surface alloying, or attaching molecular ligands. Yet, control strategies for complex, multifunctional molecules and catalysts, where selectivity is crucial, are lacking. Here, we demonstrate that submonolayer WOx with tunable coverage preferentially decorates well‐coordinated Pt terrace sites as a stable ligand. By combining experimental kinetics with probe molecules, in situ spectroscopies, and first‐principles modeling, we show that the WOx coverage on Pt modifies the metal‐to‐acid site balance while retaining the acid strength intact and results in optimal reactivity for metal‐acid catalyzed reactions at a specific metal, size, and support‐dependent WOx coverage. The oxide can also alter the reactant adsorption mode, reversing selectivity and pathways from terrace‐ to step‐dominated, as evidenced in furfural decarbonylation and hydrogenation. The insights open avenues for improving metal/metal oxide catalysts beyond the specific system. [ABSTRACT FROM AUTHOR]

ABSTRACT The rational design of noble metal‐free electrocatalysts represents one of the basic stones for fuel cell development. With the exploration of eco‐friendly nanomaterials for the investigated alcohol oxidation process, nickel‐based electrodes have been recognized as the most auspicious anodes with promoted activity and stability. In this work, a series of NiCo2O4 nanoparticles were deposited onto graphite sheets (NiCo2O4/T) introducing varied proportions of cobalt oxide species. Co‐precipitation protocol of the respective metallic hydroxides onto the carbonaceous support was followed with consecutive annealing in an air atmosphere at 400°C. The fabricated mixed metallic oxide nanopowder was physically studied using X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X‐ray analysis (EDX), X‐ray photoelectron spectroscopy (XPS), and selected area electron diffraction (SAED). Uniformly arranged nanoparticles were observed on graphite surface as evidenced by SEM and TEM. The cubic lattice structure of formed NiCo2O4 crystals was also confirmed by XRD through the defined peaks of binary metallic oxides clarifying their successful preparation scheme. The electrocatalytic properties of these NiCo2O4/T nanocatalysts were evaluated for oxidizing ethanol molecules in basic solution. Pronounced oxidation current densities were remarkably measured at NiCo2O4/T electrodes in relation to that at NiO/T. Differing the introduced cobalt oxide content into the synthesized nanocatalyst significantly controlled its catalytic performance. NiCo2O4/T‐20 exhibited the highest activity and stability among the prepared nanomaterials. Much decreased charge transfer resistances were also recorded at this electrode demonstrating its promoted electron transfer characteristics. This work could provide a reasonable route for the simple synthesis of comparable transition metallic oxides with promising attitudes for energy generation purposes. [ABSTRACT FROM AUTHOR]

2D materials, owing to their nearly atomic thickness, have emerged as promising candidates across a broad spectrum of next‐generation devices and systems. In the post‐graphene era, molybdenum‐based dichalcogenides (MoX2, where X = S, Se, Te), possessing a graphene‐like structure, represent one of the most promising subsets among 2D transition metal dichalcogenides (TMDs) due to their extensively researched and distinctive electronic, optical, and mechanical properties. Further with their distinct properties of different phases (2H, 1T) make it attractive for both fundamental and applied research. It finds diverse applications, spanning from optoelectronics to catalysis and sensor development. In this review article, the unique crystal structural properties of MoX2 are highlighted and their different synthesis methods, incorporating recent advancements in synthesis approaches discussed. Subsequently the recent development of MoX2 nanocomposite based on carbon, metal, metal oxide and various polymer discussed. Finally, the key challenges impeding the advancement of sensing applications and propose avenues for future development, drawing upon the current progress in 2D MoX2 and their nanocomposites also find mention in this review. [ABSTRACT FROM AUTHOR]

Currently, most catalysts used for photoconverting carbon dioxide (CO2) typically produce C1 products. Achieving multicarbon (C2+) products, which are highly desirable due to their greater energy density and economic potential, still remains a significant challenge. This difficulty is primarily due to the kinetic hurdles associated with the C–C coupling step in the process. Given this, devising diverse strategies to accelerate C–C coupling for generating multicarbon products is requisite. Herein, we first give a classification of catalysts involved in the photoconversion of CO2 to C2+ fuels. We summarize metallic oxides, metallic sulfides, MXenes, and metal–organic frameworks as catalysts for CO2 photoreduction to C2+ products, attributing their efficacy to the inherent dual active sites facilitating C–C coupling. In addition, we survey covalent organic frameworks, carbon nitrides, metal phosphides, and graphene as cocatalysts for CO2 photoreduction to C2+ products, owing to the incorporated dual active sites that induce C–C coupling. In the end, we provide a brief conclusion and an outlook on designing new photocatalysts, understanding the catalytic mechanisms, and considering the practical application requirements for photoconverting CO2 into multicarbon products. [ABSTRACT FROM AUTHOR]

The mutual influence of interface processes during simultaneous contact of zirconia ceramic plate with adhesion-active Cu–Ga–Ti melt (on one side of the plate) and inert to oxides liquid copper (on other side of the plate) was studied. Wetting of ceramic with metal melts was studied by sessile drop method, the structure of the interfaces was determined using SEM. Due to the dissolution of ceramic oxygen in Cu–Ga–Ti, non-stoichiometric zirconia (ZrO2-x) is formed, then ‘surplus’ zirconium from the ZrO2-x structure dissolves in the copper melt, the stoichiometry of zirconia is restored and an additional amount of oxygen dissolves in the Cu–Ga–Ti melt. It leads to a decrease in the adhesion of Cu–Ga–Ti to ceramics, while improving the wetting of ZrO2 ceramics with copper. The ZrO2–Cu–Ga–Ti interface contains copper–titanium–oxygen intermetallides with zirconia inclusions, which does not provide adhesion of metals with solid oxides. If the contact of Cu–Ga–Ti with ZrO2 is formed before contact with liquid copper, then the interface layer contains oxidized titanium, which promotes adhesion of metal to ceramic. Thus, the design of the sample affects the processes in the studied systems in the same way as the heating mode and the amount of the active component. [ABSTRACT FROM AUTHOR]

The design and development of new high-performance catalysts is one of the most important and challenging issues to achieve sustainable chemical and energy production. This Feature Article describes the synthesis of nanostructured metal oxides and phosphates mainly based on earth-abundant metals and their thermocatalytic application to selective oxidation and acid–base reactions. A simple and versatile methodology for the control of nanostructures based on crystalline complex oxides and phosphates with diverse structures and compositions is proposed as another approach to catalyst design. Herein, two unique and verstile methods for the synthesis of metal oxide and phosphate nanostructures are introduced; an amino acid-aided method for metal oxides and phosphates and a precursor crystallization method for porous manganese oxides. Nanomaterials based on perovskite oxides, manganese oxides, and metal phosphates can function as effective heterogeneous catalysts for selective aerobic oxidation, biomass conversion, direct methane conversion, one-pot synthesis, acid–base reactions, and water electrolysis. Furthermore, the structure–activity relationship is clarified based on experimental and computational approaches, and the influence of oxygen vacancy formation, concerted activation of molecules, and the redox/acid–base properties of the outermost surface are discussed. The proposed methodology for nanostructure control would be useful not only for the design and understanding of the complexity of metal oxide catalysts, but also for the development of innovative catalysts. [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]

Catalysts based on Pt single atom (SA) on metal oxides have shown tremendous potentials for alkaline hydrogen evolution reaction (HER), but they are severely limited by insufficient electron interactions of Pt sites and supports. Herein, a new methodology is developed to precisely locate Pt SAs and Pt clusters into NiCo layered double oxide (LDO) nanosheets, achieved using a dual‐ion etching process with subsequent phase transformation method. Uniquely, the Pt SAs are inserted into LDO layers to form Pt─Co bonds by occupying partial Ni positions, significantly strengthening electron interactions with NiCo LDO and promoting activity of HER. Results from density functional theory calculations indicate that the H* species are preferentially absorbed onto O sites on top of these Pt SAs, which are coupled with their adjacent Pt clusters to accelerate water dissociation in the Volmer step. As‐obtained Pt─NiCo LDO exhibits a low overpotential of 92 mV at 10 mA cm−2 and a Tafel slope of 73 mV dec−1, an excellent stability over 105 hours at 60 mA cm−2, and its mass activity is 6 times higher than commercial 20% Pt/C. This study highlights essential functions of coupling interactions between Pt SAs/clusters and LDOs to boost HER for hydrogen energy production. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) nonlayered metal compounds with porous structure show broad application prospects in electrochemistry‐related fields due to their abundant active sites, open ions/electrons diffusion channels, and faradaic reactions. However, scalable and universal synthesis of 2D porous compounds still remains challenging. Here, inspired by blowing gum, a metal‐organic gel (MOG) rapid redox transformation (MRRT) strategy is proposed for the mass production of a wide variety of 2D porous metal oxides. Adequate crosslinking degree of MOG precursor and its rapid redox with NO3− are critical for generating gas pressure from interior to exterior, thus blowing the MOG into 2D carbon nanosheets, which further act as self‐sacrifice template for formation of oxides with porous and ultrathin structure. The versatility of this strategy is demonstrated by the fabrication of 39 metal oxides, including 10 transition metal oxides, one II‐main group oxide, two III‐main group oxides, 22 perovskite oxides, four high‐entropy oxides. As an illustrative verification, the 2D transition metal oxides exhibit excellent capacitive deionization (CDI) performance. Moreover, the assembled CDI cell could act as desalting battery to supply electrical energy during electrode regeneration. This MRRT strategy offers opportunities for achieving universal synthesis of 2D porous oxides with nonlayered structures and studying their electrochemistry‐related applications. [ABSTRACT FROM AUTHOR]

The chemical absorption biological reduction process gained profound attention in NOx removal. Treatments for NOx are done popularly using NH3 in selective catalytic reduction (SCR), and deNOx is greatly influenced by catalyst. In recent years, zeolites have been widely explored in ammonia‐selective catalytic reduction (NH3‐SCR) under low‐temperature windows. Different methods were employed to juxtapose the performances of zeolite catalysts with denitrification and NH3‐SCR. In this NH3‐SCR reaction, the zeolite catalyst's sulfur and water poisoning effects were also investigated. The negatives of the low‐temperature NH3‐SCR reactions were demonstrated by using different methods. Ideally, this audit will set upon essential comprehension of the SCR response on zeolite catalysts and clear the way for future exploration to accomplish reasonable applications. The current review provides a new strategy to enhance the removal of NOx and reveals the fundamental effects of different types of sustainable catalysts for the environment. Further, the perspective of the economic aspects of each catalyst is also examined. [ABSTRACT FROM AUTHOR]

The exponential advancement of science and technology, especially within the realm of nanotechnology, has significantly expanded the applications of metal and metal oxide nanoparticles across various industrial sectors, scientific domains, and research institutions. Nickel oxide nanoparticles, in particular, have garnered considerable interest due to their unique characteristics and versatile applications. This paper comprehensively reviews NiO NPs, emphasizing their biological synthesis methods, characterization techniques, and wide‐ranging biomedical applications. These applications include their efficacy against fungal, bacterial, and viral infections, anticancer properties, and potential as innovative therapeutic agents for numerous diseases. Our findings underscore the novelty of NiO NPs in enhancing therapeutic strategies and expanding their biomedical applications, paving the way for innovative medical interventions.The objective of this review is to elucidate a thorough overview of the current research landscape, highlight recent developments, and explore the potential future directions for NiO NPs. [ABSTRACT FROM AUTHOR]

In this work, ruthenium-based catalysts were synthesized via polyol reduction method with different metal oxides as support and caesium as promoter. The samples were characterized through XRD, ICP-OES, nitrogen physisorption and XPS. Then, the catalysts were tested for ammonia synthesis in the range of temperatures 548–673 K and pressures 1–5 MPa. The synthesized catalysts allowed an ammonia production rate approximately four times higher compared with the performances of similar catalytic formulations in literature (tested at same conditions). The best performance were achieved with the Cs–Ru/CeO 2 (1% wt Cs, 5% wt Ru), reaching an ammonia production of nearly 73 mmol h−1∙g cat −1 at 673 K and 5 MPa. As showed by the XPS analysis, the increased Ce3+/Ce4+ ratio led to an enhancement of oxygen vacancies, which favoured the dissociative adsorption of nitrogen, that is the limiting step in the ammonia synthesis reaction. Such high catalytic activity can be ascribed to the beneficial effect of the polyol reduction method for the maximization of the exposure of active sites. [Display omitted] • Ru-catalysts were synthesized via polyol reduction and tested for NH 3 production. • Cs–Ru/CeO 2 enabled a NH 3 production rate of 43 mmol h−1∙g cat −1 at 673 K and 1 MPa. • Increased Ce3+/Ce4+ ratio enhanced oxygen vacancies favouring N 2 adsorption. [ABSTRACT FROM AUTHOR]

Chlorine (Cl2) is one of the most important commodity chemicals that has found widespread utility in chemical industry. Most Cl2 is currently produced via the chlorine evolution reaction (CER) at the anode of chlor–alkali electrolyzers, for which platinum group‐metal (PGM)‐based mixed metal oxides (MMOs) have been used for more than half a century. However, MMOs suffer from the use of expensive and scarce PGMs and face selectivity problems due to the parasitic oxygen evolution reaction. Over the last decade, the field of CER catalysis has seen dramatic advances in both the theory and discovery of new catalysts. Theoretical approaches have enabled a fundamental understanding of CER mechanisms and provided catalyst design principles. The exploration of new materials has led to the discovery of CER catalysts other than MMOs, including non‐PGM oxides, atomically dispersed single‐site catalysts, and organic molecules, with some of which following novel reaction pathways. This minireview provides an overview of the recent advances in CER electrocatalyst research and suggests future directions for this revitalized field. [ABSTRACT FROM AUTHOR]

Sol–gel‐based solution‐processed metal oxides have emerged as a key fabrication method for applications in thin film transistors both as a semiconducting and a dielectric layer. Here, a low‐temperature, green solvent‐based, non‐toxic, and cost‐effective solution shearing approach for the fabrication of thin aluminum oxide (AlOx) dielectrics is reported. Optimization of sustainability aspects like energy demand, and selection of chemicals used allows to reduce the environmental impact of the life cycle of the resulting product already in the design phase. Using this approach, ultra‐thin, device‐grade AlOx films of 7 nm are coated—the thinnest films to be reported for any solution‐fabrication method. The metal oxide formation is achieved by both thermal annealing and deep ultra‐violet (UV) light exposure techniques, resulting in capacitances of 750 and 600 nF cm−2, respectively. The structural analysis using microscopy and x‐ray spectroscopy techniques confirmed the formation of smooth, ultra‐thin AlOx films. These thin films are employed in organic field‐effect transistors (OFETs) resulting in stable, low hysteresis devices leading to high mobilities (6.1 ± 0.9 cm2 V−1 s−1), near zero threshold voltage (−0.14 ± 0.07 V) and a low subthreshold swing (96 ± 16 mV dec−1), enabling device operation at only ±0.5 V with a good Ion/Ioff ratio (3.7 × 105). [ABSTRACT FROM AUTHOR]

The meticulous design of heterogeneous interfaces presents a promising approach for enhancing the electrocatalytic activity of Cu-based materials in nitrate reduction reactions. Herein, we developed a self-templated metal–organic frameworks transformation strategy to synthesize hollow multi-metallic oxide materials with well-defined interfaces. By utilizing novel hollow Cu–Co bimetallic Prussian blue analogs as precursors, a hollow cage composed of ultra-small CuO/Co3O4 hetero-nanograins was successfully constructed. It was discovered that this structure greatly enhanced the electrocatalytic activity for the conversion of NO3− to NH3, achieving a remarkably high Faradaic efficiency (FE) for NH3 (with a maximum FE of 90.68%) at low overpotential ranges. Furthermore, electrochemical experiments and in situ spectroscopy provided evidence that electrochemically induced reconstruction led to the formation of synergistic sites between Cu and Co3O4. This enabled the sequential reduction of nitrate and nitrite on adjacent metal/metal oxide phases, resulting in the rapid generation of NH3. [ABSTRACT FROM AUTHOR]

The catalytic relevance of different surface functionalities present on hydrotalcite‐derived Mg−Al mixed metal oxides (MgAlO) are investigated in the context of ethanol upgrade to n‐butanol. The catalyst structure and active sites were altered through changes in the Mg/Al ratio and introduction of additional redox metal oxide functionalities. After performing a series of catalytic activity tests, operando FTIR characterization, TGA measurements and in situ active center titration; qualitative and quantitative relationships between catalyst structure and catalytic performance are obtained. We found the Mg−Al mixed metal oxides system can catalyze the ethanol to n‐butanol process through a Guerbet reaction pathway, though the process is kinetically limited. By introducing redox active metal oxides to the catalyst formulation, such as MoO3 or V2O5, this problem can be partially solved, but at a cost of losing a significant fraction of high‐strength basic centers which are the most catalytically relevant function in the system, as they control enolate formation rates leading to the C−C coupling step required for n‐butanol formation. [ABSTRACT FROM AUTHOR]

In this study, nickel supported on various metal oxides were prepared by simple impregnation and the performance for CO2 methanation was tested. The oxide supports were all prepared by thermal decomposition of metal salts to provide comparable oxide properties such as surface area. Among the investigated oxides, nickel supported on CeO2 and Y2O3 showed the highest CO2 conversion of 90% at 320 °C with highest CH4 selectivity of 99%. The order of catalyst activity (XCO2@320°C) was reported: Ni/CeO2 ~ Ni/Y2O3 > > Ni/La2O3 > Ni/ZrO2 > Ni/Al2O3 > Ni/MgO > Ni/CaO > > Ni/MnO. The physicochemical properties of the catalysts were analyzed by TEM, BET, XRD, ICP, H2-TPR, CO2-TPD, H2 chemisorption, TGA, Raman, and XPS. From the characterization results, the catalyst activity was independent to specific surface area of catalyst and crystallite size of Ni. The amount of oxygen vacancies and weak-to-medium basic sites exhibited major roles for enhancing catalyst activity. The CeO2 and Y2O3 as reducible oxide supports not only provided abundant oxygen vacancies / basic sites, but also promoted Ni dispersion with appropriate interaction between metal and support, resulting in higher reducibility at low temperature. The reduction of catalyst at high temperature can significantly improve the performance of Ni supported on non-reducible MgO. However, the Ni/CeO2 and Ni/Y2O3 reduced at high temperature suffered from coalescence of CeO2 and Y2O3, though Ni crystallite sizes are well preserved from sintering. [ABSTRACT FROM AUTHOR]

The utilization of electroplating sludge (ES) to derive metal oxide functional materials is a key strategy, as it enables the recycling of valuable elements, mitigates environmental risks, and aligns with green, low-carbon development strategies. Nevertheless, the development of metal oxide composite functional materials with distinctive structures and properties derived from ES continues to present several challenges. Herein, we synthesized CuFe2O4/MgFe2O4 metal oxide composites from ES by one-step hydrothermal method. As-obtained CuFe2O4/MgFe2O4 metal oxide composites (MMOs) have a unique layered structure, richer mesoporous and microporous structures, activity sites. When evaluated as an adsorbent for Congo red (CR), as-synthesized CuFe2O4/MgFe2O4 with layered structure composite exhibited excellent adsorption capacity (1039.1 mg/g) and reusability (85.55% after five cycles), which was superior to most similar adsorbents reported till date. Such improvement is explored to mainly originate from two respects: the physical adsorption facilitated by the abundant pores formed through the stacking and growth of CuFe2O4 and MgFe2O4, and the chemisorption resulting from surface complexation and hydrogen bonding between the MMOs and CR. This strategy to directly transform ES into functional materials shows great promise both in waste management and preparation of robust adsorbents for wastewater treatment. [ABSTRACT FROM AUTHOR]

High‐performance rechargeable aluminum‐sulfur batteries (RASB) have great potential for various applications owing to their high theoretical capacity, abundant sulfur resources, and good safety. Nevertheless, the practical application of RASB still faces several challenges, including the polysulfide shuttle phenomenon and low sulfur utilization efficiency. Here, we first developed a synergistic copper heterogeneous metal oxide MoO2 derived from polymolybdate‐based metal‐organic framework as an efficient catalyst for mitigating polysulfide diffusion. This composite enhances sulfur utilization and electrical conductivity of the cathode. DFT calculations and experimental results reveal the catalyst Cu/MoO2@C not only effectively anchors aluminum polysulfides (AlPSs) to mitigate the shuttle effect, but also significantly promotes the catalytic conversion of AlPSs on the sulfur cathode side during charging and discharging. The unique nanostructure contains abundant electrocatalytic active sites of oxide nanoparticles and Cu clusters, resulting in excellent electrochemical performance. Consequently, the established RASB exhibits an initial capacity of 875 mAh g−1 at 500 mA g−1 and maintains a capacity of 967 mAh g−1 even at a high temperature of 50 °C. [ABSTRACT FROM AUTHOR]