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Cu serves as a promising electrocatalyst for converting CO2 into valuable C2 products in CO2 reduction reactions (CO2RR). However, instability in CO* formation is crucial for CO2 adsorption‐ desorption still remains a challenge under reduction conditions. This study explores the impact of lanthanide oxide, particularly CeO2, on Cu‐based catalytic performances. By leveraging Ce's distinctive electronic structure, CO* species are stabilized during the reaction in CeO2─Cu2O, resulting in exceptional catalytic performance for CO2 electroreduction to C2 products. Hybridizing CeO2‐Cu2O with graphene aerogel enhances electrochemical active surface area and CO2RR efficiency. The resulting CeO2─Cu2O(10%)/GA electrocatalyst exhibits a remarkable faradaic efficiency for C2 products, exceeding 62%, alongside exceptional stability over 80 h with wide potential window (−0.8 to −1.2 V) using a H‐cell. Systematic investigations elucidate the intricate interplay between surface properties and catalytic activity. Furthermore, a solar cell‐ powered CO2 reduction system demonstrates consistent performance (−27.8 mA cm−2 at 3.46 V) under solar radiation of ≈100 mW cm−2, showcasing outstanding stability with nearly 100% retention over 4 h of continuous illumination. In short, by harnessing catalytic and electronic effects, this innovation advances the development of electrocatalysts with heightened CO2‐to‐C2 selectivity, bridging fundamental research with technological innovation to tackle critical global challenges. [ABSTRACT FROM AUTHOR]

[Display omitted] Li metal batteries (LMBs) are among the most promising options for next-generation secondary batteries under the rapidly growing demand for high-energy–density electrochemical energy storage. However, the implementation of LMBs are hindered by major obstacles such as dentritic Li deposition and low cycling Coulombic efficiency. A practical functional separator is developed in this study, which consists of a Lewis acidic mixed oxide of ZrO 2 -SiO 2 -Al 2 O 3 as a functional coating with anion anchoring ability to modulate ion transport in the vicinity of the Li metal anode, delivering a high Li+ transference number of 0.88 in carbonate electrolytes that suppresses dendrite formation. The strong Lewis acid sites in ZrO 2 -SiO 2 -Al 2 O 3 originate from coordinatively unsaturated Zr4+ ions, which immobilize anions and reduce their decomposition rate. This significantly improves the chemical stability of the electrolyte and induces a more stable solid electrolyte interphase layer. The modified separator enables an anode-free cell containing a high-loading LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode to present stable charge and discharge cycling for 150 cycles at 0.5C. By effectively suppressing Li dendrite growth and supporting the long-term operation of anode-free LMBs, this study offers a novel approach to rationally design mixed oxides with high Lewis acidity for functional separators. [ABSTRACT FROM AUTHOR]

New SCR catalysts based on Mn supported on simple or mixed aerogel oxides (Mn/ZrO2, Mn/CeO2-ZrO2 and Mn/CeO2-ZrO2-SO42−) were prepared for selective catalytic reduction of nitrogen oxide by ammonia (NO-SCR by NH3). One step sol gel method followed by supercritical drying process were used for elaborating the catalytic supports, however, Mn species were incorporated into aerogels via impregnation method. Structural, textural, acidic and redox properties of samples were studied using XRD; BET and porosity measurements; NH3-TPD and H2-TPR techniques. The results revealed that Mn/ZrO2 and Mn/CeO2-ZrO2 solids develop mesoporous texture, good crystallinity of zirconia tetragonal phase and nano-sized particles but exhibit a poor NO-SCR activity. The addition of SO42− induces a disorder in ZrO2 structure but it generates very active strong acid sites for the high temperature NO reduction. 100% NO conversion into N2 was achieved above 400 °C over the new Mn/CeO2-ZrO2-SO42− catalytic system. [ABSTRACT FROM AUTHOR]

Environmental remediation evinces sensitive detection and elimination of contaminants from the environment. Recent investigations delineate nanomaterials as potentially useful agents in environment remediation. In this investigation, we have developed multifunctional CdO‐ZnO nanocomposite (NCs) for efficient degradation of organic dyes and sensitive detection of nitrite ions which also exhibits excellent luminescence and antioxidant properties. The CdO‐ZnO NCs were developed through a facile method which improved the yield quantity by decreasing the energy consumption there by reducing the cost. Thus synthesized CdO‐ZnO NCs were characterized through X‐ray diffraction, FT‐IR, SEM, TEM, EDX studies. These studies confirmed the successful formation of CdO‐ZnO composite and the average particle size of the NCs was found to be ~50 nm. Selective reduction of harmful industrial organic dyes from the water bodies is one of the important aspects of water pollution. As prepared CdO‐ZnO NCs degraded the MB dye completely in 30 min under visible light irradiation. The effect of various parameters such as catalytic load, dye concentration and pH on the degradation of dye was assessed and the NCs exhibited maximum degradation efficiency at 25 mg of catalytic load and alkaline pH of 11. The photoluminescence studies reveal that the NCs have inherent excellent luminescence property by exhibiting the emission band at 277 and 282 nm. From electrochemical studies, the CdO‐ZnO NCs proclaimed magnificent nitrite sensing property with the LOD value of 9.8 μM. Additionally, antioxidant studies disclosed that NCs remarkably scavenged the DPPH free radicals with IC50 value of 249 μg/mL. Thus, this study establishes simple method for the development of efficient mixed oxide material CdO‐ZnO for multifunctional properties that could find industrial applications. [ABSTRACT FROM AUTHOR]

Four-component oxide catalysts MnOx–CuO–ZrO2–CeO2 are synthesized by co-precipitation with varying the calcination temperature from 400 °C to 800 °C. Formation and decomposition processes in mixed oxides are studied by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The redox properties of the obtained samples are tested by temperature-programmed hydrogen reduction, and the catalytic characteristics are examined in the CO oxidation reaction. At 400-600 °C homogeneous solid solution MnxCuyZrzCeqO2 with the fluorite structure is formed. Temperature elevation to 700-800 °C facilitates the gradual decomposition of initial oxide, with manganese and copper cations leaving its composition in the form of highly dispersed CuO and CuxMn3–xO4 particles. The occurrence of different active states in the catalyst and their transitions into each other under the temperature effect is shown to maintain the high activity in the CO oxidation reaction up to 800 °C. [ABSTRACT FROM AUTHOR]

Acid–base M2+MgAlO and M2+AlO mixed oxides (where M2+ = Mg, Cu, Co, Zn, and Ni) were obtained by thermal decomposition of the corresponding layered double hydroxide (LDH) precursors and used as catalysts for cyclohexanol and benzaldehyde condensation under solvent-free conditions. The catalysts were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and temperature-programmed desorption of CO2 (TPD-CO2). Gas chromatography–mass spectroscopy (GC/MS) was used for the identification and quantification of the product mixtures. In the reaction of cyclohexanol and benzaldehyde on M2+MgAlO and MgAlO catalysts, a 2,6-dibenzylidene-cyclohexanone was obtained as the main product as a result of consecutive one-pot dehydrogenation of cyclohexanol to cyclohexanone and subsequent Claisen–Schmidt condensation. In the reaction mixture obtained in the presence of NiAlO, CoAlO, and ZnAlO catalysts, a cyclohexyl ester of 6-hydroxyhexanoic acid was detected together with the main product. This is most likely a by-product obtained after the oxidation, ring opening, and subsequent esterification of the cyclohexanol. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen evolution from water is investigated in Ba–Sr–Ta–O layered compounds possessing two different crystal structures: Sr 2 Ta 2 O 7 (S.G. Cmcm, a (110) type layered pervoskite), and BaSrTa 2 O 7 (S.G. Immm, a (100) type layered perovskite). High purity samples of BaSrTa 2 O 7 and Sr 2 Ta 2 O 7 are successfully prepared by solid state reaction. Hydrogen production under UV irradiation is 26% larger in BaSrTa 2 O 7 (15.2 mmol g−1) than in Sr 2 Ta 2 O 7 (11.4 mmol g−1). The band gaps determined by diffuse reflectance spectroscopy (DRS) are 4 eV and 4.6 eV for BaSrTa 2 O 7 and Sr 2 Ta 2 O 7 , respectively. Density Functional Theory (DFT) calculations provide insights into the crystal and electronic structures of Sr 2 Ta 2 O 7 , BaSrTa 2 O 7 , and their derived series Sr 2-x Ba x Ta 2 O 7 (0 ≤ x ≤ 1). It is found that independently of the Sr/Ba content, the BaSrTa 2 O 7 -derived series show a ∼0.6 eV lower band gap and a wider conduction band than the Sr 2 Ta 2 O 7 -derived series. DFT results indicate that the enhanced hydrogen production of BaSrTa 2 O 7 is related to particular features of its crystal structure which favor Ta–Ta interactions. [Display omitted] • Two Ta-layered perovskites with different structure are unveiled as UV-photocatalysts • Accumulated H 2 evolution is 26 % higher in BaSrTa 2 O 7 than in Sr 2 Ta 2 O 7 • Experiments and calculations agree on a narrower band gap for BaSrTa 2 O 7 • Ba/Sr composition has a minor impact on the crystal and electronic structures • The BaSrTa 2 O 7 crystal structure propitiates the enhancement of H 2 production [ABSTRACT FROM AUTHOR]

In this study, the catalytic activity of calcined M3Al (M: Sr, Cd, Ni, Co, and Ca) and the effect of replacing divalent cations with Ca2+ in calcined MxCa3 − xAl hydrotalcite on the catalytic conversion of benzaldehyde and acetophenone to chalcone via Claisen–Schmidt condensation has been investigated. A series of M3Al and MxCa3 − xAl were synthesized by the co-precipitation method and characterized by SEM, BET, FT-IR, EDS, XRD, CO2-TPD techniques, and the Hammett indicator method. The results showed that the synthesized samples have normal surface area, high crystallinity, and three types of moderate, strong, and stronger basic sites. The catalytic activity is effectively dependent on the number of stronger alkaline sites. The effects of different parameters such as calcination temperature, solvents, catalyst amount, catalyst reusability, and the effects of electron-donating and electron-withdrawing groups were investigated. In optimum conditions over 0.04 wt% Sr0.5Ca2.5Al catalyst, at atmospheric pressure, 60 °C, in ethanol, yield (%) of chalcone was achieved at 87%. [ABSTRACT FROM AUTHOR]

Powdered Ni-based catalysts exhibit good performance in the dry reforming of methane (DRM); however, they suffer from limited industrial applicability. Structured monolithic catalysts can overcome these limitations. In this sense, we present the synthesis of Ni–Ce mixed oxide-type catalysts immobilized in cordierite monoliths using a simple coprecipitation method and slurry coating without additives using hydrotalcite precursors for catalyst preparation. Our research explores the role of Ce (0–7 % w/w) as a promoter and the impact of immobilizing mixed oxides (MO) within cordierite monoliths on the physicochemical properties and catalytic performance of non-previously H 2 -reduced materials in DRM at 700 °C. Our findings reveal the favorable impact of Ce on the physicochemical properties of the catalyst in both the powder and monoliths, including smaller crystallite sizes, enhanced CO 2 adsorption, and reducibility with higher Ce loading. The immobilized mixed oxide (MO) maintained its crystalline structure and formed stable, uniform layers with thicknesses below 10 μm in the monoliths. The powders exhibited stable conversions of 70–80% for CH 4 and 66–75% for CO 2 , whereas the monoliths showed conversions of 85–90% for CH 4 and 80–90% for CO 2 at 700 °C and 94,680 mL·g cat −1·h−1. A higher catalyst loading in the monoliths did not result in detrimental catalytic conversion. On average, the monoliths had a higher H 2 /CO ratio (1.25–1.5) compared to the powders (1–1.25), which may explain the increased coke formation rate in the monoliths from methane cracking. Ce improved the stability and reduced coke formation, particularly when the space velocity was lower. This research highlights the significant advantages of immobilizing mixed oxides (MO) in monolithic structures, making them highly promising for potential industrial scale-up. Their stability, recoverability, elimination of high-cost H 2 reduction, and reusability in subsequent catalytic tests contributed to their favorable characteristics. [Display omitted] • Coprecipitation simplifies slurry coatings for monolith immobilization. • Monoliths were prepared without additives. • The monoliths exhibited high stability and consistent performance upon reuse. • Ce improved stability and reduced coke formation at lower space velocities. • Immobilized catalysts produced more carbon, but no pressure drops were observed. [ABSTRACT FROM AUTHOR]

The rapid emergence of intelligent textile-based sensors has sparked considerable interest within the scientific community. A pivotal factor in advancing these sensors is the development of semiconductors with tailored band energy levels to enhance their optical properties. This enhancement primarily arises from efficient carrier separation and interfacial charge transfer processes. In pursuit of these objectives, our study presents a novel approach to fabricate flexible thin films composed of mixed oxides, specifically zinc oxide and cadmium tungstate (ZnO/CWO), within a chitosan (CS) matrix, utilizing a cost-effective method. We conducted a comprehensive characterization of the fabricated samples, encompassing structural, morphological, and optical analyses. Techniques such as X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FESEM), iono/photoluminescence, and scintillation strategies were employed. The findings from XRD and Raman spectroscopy unequivocally confirm the presence of hexagonal ZnO and monoclinic CdWO4 structures within the thin film. Notably, the ZnO/CWO composite thin films exhibit robust emissions in the blue-green and orange spectral regions compared to pure CS at room temperature. This phenomenon occurs following excitation by a 290 nm wavelength light source and a proton beam serving as an ionizing radiation source. Furthermore, FESEM/TEM analysis reveals that the synthesized ZnO/CWO composite nanoparticles predominantly exhibit a diverse range of shapes, including cubic, rod-like, and spherical, with an average diameter size of approximately 20–80 nm, demonstrating excellent dispersion within the chitosan matrix. The results obtained in this study suggest that the prepared flexible composite film holds significant promise for future applications in adaptable optical devices. [ABSTRACT FROM AUTHOR]

AbstractOptimizing materials and associated structures for detecting various environmental gas pollutant concentrations has been a major challenge in environmental sensing technology. Semiconducting metal oxides (SMOs) fabricated at the nanoscale are a class of sensor technology in which metallic species are functionalized with various dopants to modify their chemiresistivity and crystalline scaffolding properties. Studies focused on recent advances of gas sensors utilizing metal oxide nanostructures with a special emphasis on the structure-surface property relationships of some typical n-type and p-type SMOs for efficient gas detection are presented. Strategies to enhance the gas sensor performances are also discussed. These oxide material sensors have several advantages such as ease of handling, portability, and doped-based SMO sensing detection ability of environmental gas pollutants at low temperatures. SMO sensors have displayed excellent sensitivity, selectivity, and robustness. In addition, the hybrid SMO sensors showed exceptional selectivity to some CWAs when irradiated with visible light while also displaying high reversibility and humidity independence. Results showed that TiO2 surfaces can sense 50 ppm SO2 in the presence of UV light and under operating temperatures of 298–473 K. Hybrid SMO displayed excellent gas sensing response. For example, a CuO–ZnO nanoparticle network of a 4:1 vol.% CuO/ZnO ratio exhibited responses three times greater than pure CuO sensors and six times greater than pure ZnO sensors toward H2S. This review provides a critical discussion of modified gas pollutant sensing capabilities of metal oxide nanoparticles under ambient conditions, focusing on reported results during the past two decades on gas pollutants sensing. [ABSTRACT FROM AUTHOR]

The mesoporous catalytic composite material was prepared from both stover ash (as a source of mixed oxides) and treated rice straw with very low residue on ignition (as a pore-capping agent). X-ray diffraction and BET surface analyses of the as-prepared mesoporous mixed oxides (MMO) exhibited a partially crystalline structure with an average pore diameter of 16.4 nm. To modify the optical properties, Ni nanoparticles were loaded onto the MMO surface via the reduction with hydrazine. Both MMO and the modified material, namely Ni-MMO, were investigated by HR-TEM, IR, X-ray diffraction, BET surface analyses, XPS, PL spectra, and UV-Visible reflectance measurements. In a good agreement, all tests confirmed that Ni nanoparticles interacted with oxides on the surface with restructuring and a new potential crystal system. XPS revealed that Ni generates surface oxygen vacancies (SOV) which induced sub-band levels to stabilise e-/h* pairs. Ni-MMO with low PL intensity showed a high photocatalytic activity in degradation of Rhodamine B dye with a maximum of 99.1% after 180 min under visible irradiation and catalyst dose of 1 g L−1. The reusability test for Ni-MMO exhibits the catalyst stability in four consecutive cycles. [ABSTRACT FROM AUTHOR]

Examining proficient electro‐catalyst from earth abundant and sustainable material is highly required for clean energy generation and a step toward fuel cell. In this study, ZnO/ZrO2 mixed metal oxide has been synthesized using organic chemicals in a straightforward and environmentally friendly manner. The greener routes are not only employed for the synthesis of nano structured material but they also improve the charge transfer properties of material in term of high surface area. The as prepared nano‐oxides were probed for phase structure, morphology, surface chemistry and optical properties by spectroscopic techniques. The embedded phyto‐functionalized compounds in the prepared nano‐material were probed by FTIR and GC–MS demonstrating the phyto‐functionalization of ZnO/ZrO2 nanomaterial. Thereafter, effects of functionalization were observed on the electrochemical behavior of synthesized material. The electrochemical investigation revealed remarkable catalytic activity of fabricated ZnO/ZrO2 with small overpotential and Tafel slope for current density of 10 mA cm−2. Therefore, current work demonstrated the promising electrocatalytic potential of fabricated mixed metal oxide and paved a cost effective and efficient organic template to synthesize binary or ternary mixed oxide with enhanced electrocatalytic properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Brønsted sites generated by SiO 2 on Lewis acidic ZrO 2 , TiO 2 , Nb 2 O 5 , or Al 2 O 3. • Acid strength quantified by TMPO chemisorption 31P NMR. • Brønsted acid strength increased with MOx Lewis acidity, as Al 2 O 3 > Nb 2 O 5 > TiO 2 > ZrO 2. • Hydroalkoxylation rates maximized at near-monolayer silica loading. • Hydroalkoxylation rates scaled with Brønsted acidity. Mixed oxides are ubiquitious solid acid catalysts for a number of transformations. Here, the chemistry of mixed oxide interfaces was experimentally probed by constructing model SiO 2 on MO x interfaces using a liquid-phase, stoichiometrically-controlled deposition of tetraethyl orthosilicate (TEOS). Catalytically active Brønsted sites were generated in four series of overcoated SiO 2 on metal oxide materials prepared by depositing TEOS onto Al 2 O 3 , anatase TiO 2 , Nb 2 O 5 , and ZrO 2. Pyridine DRIFTS studies indicate that the acidity of deposited silanol groups was enhanced by interaction with the metal oxide surface, suggesting that pseudo-bridging silanol type structures were formed. Trimethylphosphine oxide (TMPO) 31P NMR experiments showed that Brønsted acid strength varied in the overcoated materials, with increasing strength in the following order: SiO 2 /ZrO 2 < SiO 2 /TiO 2 < SiO 2 /Nb 2 O 5 < SiO 2 /Al 2 O 3. This order correlated with the Lewis acidity and chemical hardness of the underlying metal oxides. The catalytic performance of the materials was evaluated in the liquid-phase hydroalkoxylation of dihydropyran with n-octanol, revealing that activity was highly dependent on SiO 2 loading, which impacted the density of acid sites, and scaled exponentially with Brønsted acid strength, determined by the core metal oxide identity. Brønsted acid strength appears to be the key driver of the materials' activity, with the highest areal rate of 2.2 mmol / m2 – h being measured over SiO 2 /Al 2 O 3. This study shows that SiO 2 -overcoated materials are a systematically tunable class of catalysts that can be applied to acid catalyzed reactions. [ABSTRACT FROM AUTHOR]

A novel bimetallic mixed oxide catalyst Mn2CoO4 was prepared by co-precipitation method・ The catalyst was characterized and analyzed by X-ray diffraction analysis, electron microscope-energy spectrum analysis and other means・ It is used to activate persulfate (PMS) to degrade Rhodamine B (RhB). The results show that when the dosage of Mn2CoO4 is 0. 25 g/L and the dosage of PMS is 0. 5 mmol/L, the removal efficiency was highest of RhB after 15 min of reaction. The removal rate is 99. 13%, the first-order reaction rate constant is as high as 0. 343 9 min 1, and the reusability is excellent. The quenching test results showed that the sulfate radical (SO4 •) played a major role in the degradation process, and the hydroxyl radical (• OH) only played a weak role, and the superoxide radical (• O2) did not participate in the reaction. [ABSTRACT FROM AUTHOR]

Single phase CuCoMgAl-layered hydroxides were obtained by making fine adjustment to their composition through changing the (Co + Cu)/Mg = 0.5; 1; 2; 3 and Co/Cu = 0.5; 1; 2 ratios. The rise of Co/Cu in systems contributed to the increase in their thermal stability. CuCoMgAl-catalysts showed high selectivity of carbonyl group hydrogenation in furfural and 5-hydroxymethylfurfural. In furfural hydrogenation, the selectivity to furfuryl alcohol was more than 99%, and in 5-hydroxymethylfurfural hydrogenation, the selectivity to 2,5-hydroxymethyl furfural was 95%. The surface of the samples with different Co/Cu after calcination and reduction was the same and had a «core-shell» structure (TEM). «Core» consisted of Cu and Co metallic particles. «Shell» consisted of CuCoMgAlOx mixed no-stoichiometric spinel oxides. There was no sintering or change in size of the metallic particles after the reaction. For the sample with Co/Cu = 1, their phase composition after reaction remained unchangeable. The increase of Co/Cu led to the formation of an X-ray amorphous phase after the reaction. This suggests the decrease in structural stability of this sample. The obtained results prove the prospects of using bimetallic CoCu-systems for hydrogenation of furan aldehydes, and opens up new directions for further research and improvement. [ABSTRACT FROM AUTHOR]

The increase of consciousness towards global warming and the need to reduce greenhouse gas emissions lead to the necessity of finding alternative applications based on easy-to-use materials in order to control and reduce global CO2 emissions. Layered Double Hydroxides (LDHs) and LDH-derived materials are potentially good adsorbents for CO2, thanks to their low cost, easy synthesis, high sorption capacity, and surface basicity. They have been intensively studied in CO2 capture at high temperature, presenting variable sorption capacities for MgAl LDHs with the same composition, but prepared under different synthesis conditions. The ambient temperature coprecipitation synthesis method is an attractive one-step procedure to synthesize LDHs under mild conditions, with low energy consumption and short synthesis time. The present study is based on the synthesis and characterization of hydrotalcites by a mild-conditions coprecipitation process and the production of derived mixed oxides to be used as CO2 adsorbents. A critical comparison to similar materials is reported. Moreover, the effect of the surface basicity of the derived mixed oxides (measured by adsorption calorimetry) and the CO2 sorption capacity are discussed, showing a linear correlation between the amount of weak and very strong basic sites and the CO2 adsorption behavior. [ABSTRACT FROM AUTHOR]

The CoAl hydroxides with Co/Al ratios of 2 and 4 were synthesized using traditional coprecipitation and a mechanochemical method. The structural properties of the samples at all stages of catalyst preparation, the transformations occurred on the reduction of cobalt from corresponding oxides, the textural characteristics of calcined and reduced systems, and the size, morphology, and composition of particles formed after high-temperature treatments were studied in detail. It was established that the synthesis procedure of CoAl hydroxides has a significant effect on the phase composition and properties of the resulting systems. The layered double hydroxide phase was formed only when the coprecipitation method was used. The mechanochemical approach made it possible to obtain materials with a higher specific surface area. According to TEM data, the samples synthesized by coprecipitation (after oxidative and reductive treatments) had a core–shell structure, where the core included metallic Co atoms and the shell mainly consisted of CoAl spinel. The samples prepared by the mechanochemical method had highly dispersed Co nanoparticles on their surface. The catalysts based on CoAl systems prepared by the mechanochemical method were more active in the hydrogenation of furfural: its conversion reached 97% on a sample with the ratio Co/Al = 4. In this case, the selectivity for furfuryl alcohol formation on the studied catalysts was almost 100% regardless of the synthesis procedure and Co/Al ratio. [ABSTRACT FROM AUTHOR]

A rational synthetic approach is introduced to enable hydrogen insertion into oxides by forming a solid solution of a reducible oxide with a less reducible oxide as exemplified with RuO2 and TiO2 (Ru_x, a mixture of x% RuO2 with (100−x)% TiO2). Hydrogen exposure at 250 °C to Ru_x (Ru_x_250R) results in substantial hydrogen incorporation accompanied by lattice strain that in turn induces pronounced activity variations. Here, we demonstrate that hydrogen incorporation in mixed oxides promotes the oxidation catalysis of propane combustion with Ru_60_250R being the catalytically most active catalyst. [ABSTRACT FROM AUTHOR]

The reaction to obtain furan alcohols is one of the most important in the upgrading of furan derivates. An attractive route is the transfer hydrogenation of furfural using acidic‐basic catalysts. In this work, mixed oxides derived from ternary hydrotalcites were employed to obtain furfuryl alcohol from furfural assisted by microwave irradiation. These materials were characterized via X‐ray diffraction (XRD), N2 adsorption‐desorption isotherms, Fourier‐transform infrared (FTIR) and the CO2 temperature‐programmed desorption (CO2‐TPD) analyses. The lamellar structure of hydrotalcite‐type materials collapses during the calcination process, resulting in the loss of carbonate anions and hydroxyl groups, present in the interlayer space. This leads to the formation of mixed oxides that exhibit larger surface areas. Furthermore, these changes alter the basic nature of these materials, giving rise to the formation of strong basic sites. The reaction was studied using containing Co2+ and Ni2+ in their structure and was then optimized using distinct primary and secondary alcohols as hydrogen donor sources, as well as distinct temperatures and initial concentrations of furfural. The yields to furfuryl alcohol are strongly dependent on the type of Me2+ in layered oxides mainly due to higher basicity and to the donor employed in the reaction. The mixed oxide containing Co2+ showed complete conversion of furfural and higher yields to furfuryl alcohol (>95 %) at short times of reaction (<1 h). [ABSTRACT FROM AUTHOR]

CeO2-TiO2 is an important mixed oxide due to its catalytic properties, particularly in heterogeneous photocatalysis. This study presents a straightforward method to obtain 1D TiO2 nanostructures decorated with CeO2 nanoparticles at the surface. As the precursor, we used H2Ti3O7 nanoribbons prepared from sodium titanate nanoribbons by ion exchange. Two cerium sources with an oxidation state of +3 and +4 were used to obtain mixed oxides. HAADF–STEM mapping of the Ce4+-modified nanoribbons revealed a thin continuous layer at the surface of the H2Ti3O7 nanoribbons, while Ce3+ cerium ions intercalated partially between the titanate layers. The phase composition and morphology changes were monitored during calcination between 620 °C and 960 °C. Thermal treatment led to the formation of CeO2 nanoparticles on the surface of the TiO2 nanoribbons, whose size increased with the calcination temperature. The use of Ce4+ raised the temperature required for converting H2Ti3O7 to TiO2-B by approximately 200 °C, and the temperature for the formation of anatase. For the Ce3+ batch, the presence of cerium inhibited the conversion to rutile. Analysis of cerium oxidation states revealed the existence of both +4 and +3 in all calcined samples, regardless of the initial cerium oxidation state. [ABSTRACT FROM AUTHOR]

The structural and compositional flexibility of perovskite oxides and their complex yet tunable redox properties offer unique optimization opportunities for thermochemical energy storage (TCES). To improve the relatively inefficient and empirical‐based approaches, a high‐throughput combinatorial approach for accelerated development and optimization of perovskite oxides for TCES is reported here. Specifically, thermodynamic‐based screening criteria are applied to the high‐throughput density functional theory (DFT) simulation results of over 2000 A/B‐site doped SrFeO3−δ. 61 promising TCES candidates are selected based on the DFT prediction. Of these, 45 materials with pure perovskite phases are thoroughly evaluated. The experimental results support the effectiveness of the high‐throughput approach in determining both the oxygen capacity and the oxidation enthalpy of the perovskite oxides. Many of the screened materials exhibit promising performance under practical operating conditions: Sr0.875Ba0.125FeO3−δ exhibits a chemical energy storage density of 85 kJ kgABO3−1 under an isobaric condition (with air) between 400 and 800 °C whereas Sr0.125Ca0.875Fe0.25Mn0.75O3−δ demonstrates an energy density of 157 kJ kgABO3−1 between 400 °C/0.2 atm O2 and 1100 °C/0.01 atm O2. An improved set of optimization criteria is also developed, based on a combination of DFT and experimental results, to improve the effectiveness for accelerated development of redox‐active perovskite oxides. [ABSTRACT FROM AUTHOR]

Ethanol has been used as a renewable hydrogen‐donor in the conversion of a lignin model molecule in subcritical conditions. Noble metal‐free porous mixed oxides, obtained by activation of Cu−Ni−Al and Cu−Ni−Fe layered double hydroxide (LDH) precursors, have been used as heterogeneous catalysts for Meerwein‐Ponndorf‐Verley (MPV) hydrogen transfer and further hydrogenation by ethanol dehydrogenation products. Both the Cu/(Cu+Ni) ratio and the nature of the trivalent cation (Al or Fe) affect the activity of the catalysts, as well as the selectivity towards the different steps of the hydrogenation reactions and the cleavage of lignin‐like phenylether bonds. Accounting for the peculiar behaviour of Cu2+ and M(III) cations in the synthesis of LDHs, the coprecipitation of the precursors has been monitored by titration experiments. Structural and textural properties of the catalysts are closely related to the composition of the LDH precursors. [ABSTRACT FROM AUTHOR]

The application of open cell foams as catalytic supports has been developed in recent years due to their interesting features: large specific surface area (>300 m2 m−3), high void fractions (>0.9) and enhanced internal mass transport. Catalytic foams are highly appealing for the development of structured reactors, especially for multiphase systems. In this paper, catalytic packing material with potential application in structured reactors was developed. Aluminum foams with different macropore sizes were chosen as support for a TiO2−WOx catalyst. The main features, geometric and structural, of the foams were established. At optimized conditions a maximum catalyst loading of 234 kgcatalyst m−3support was obtained, while maintaining significant void fraction (>0.8). The structured catalyst was successfully implemented in batch reactor for a model reaction, esterification of glycolic acid with ethanol. It was shown that the catalyst does not lose performance during the coating steps and remains active for at least 3 catalytic runs, i. e. 18 h. [ABSTRACT FROM AUTHOR]

Herein, a new method for synthesizing advanced nanocomposite materials based on tungsten, molybdenum, and titanium oxides by pulsed underwater plasma is reported. This is an environmentally friendly, energy‐saving, and simple method for obtaining bimetallic oxide nanoparticles with inhomogeneous defect structures. The chemical composition and morphology of the obtained particles are explored by electron microscopy and X‐ray diffraction spectroscopy. Four types of mixed‐oxide particles of tungsten–molybdenum and tungsten–titanium are synthesized and used to make the photoanodes for dye‐sensitized solar cells (DSSCs). The best DSSC shows a fill factor of 51% and a short‐circuit current density of 4.8 mA cm−2, resulting in a conversion efficiency of 4.11% and an improvement over the cells prepared from pure titanium or tungsten oxides. [ABSTRACT FROM AUTHOR]

Mesostructured mixed metal oxides are one of the best candidates for various oxidations. Here, mesostructured Cux/Cey mixed oxides with various Cu/Ce ratios were prepared using mesoporous silica as a hard template to improve their selectivity and efficiency as the oxidative catalysts. Investigation of the different ratios of Cu/Ce showed that all catalysts are significantly more active than their salts in the oxidation of alcohols and sulfides with some green oxidants. The results demonstrated that the balance of the number of active catalytic centers (concentration of Cu) and the structural characteristics (surface area and oxygen vacancy) determine the activity of the catalysts. It also seems to be a powerful interplay among copper and cerium ions that helps the reduction of both Cu (II) and Ce (IV). [ABSTRACT FROM AUTHOR]

Ni(Mg)Al-layered hydroxides with molar ratios of (Ni + Mg)/Al = 2, 3, 4 and Ni/(Ni + Mg) = 0.1, 0.3, 0.5, 0.7 were synthesized by mechanochemical activation. It has been proven that the phase composition of the samples was presented by a single hydrotalcite phase up to Ni/(Ni + Mg) = 0.5. For the first time, catalysts based on Ni(Mg)Al-layered hydroxides prepared by a mechanochemical route have been studied in the reaction of furfural hydrogenation. The correlation between furfural conversion, the selectivity of the products, and the composition of the catalysts was established. The effect of phase composition, surface morphology, and microstructure on the activity of the catalysts was shown by XRD, SEM, and TEM. It was found that catalysts with Ni/(Ni + Mg) = 0.5 have the highest furfural conversion. Herewith, the product selectivity can be regulated by the (Ni + Mg)/Al ratio. [ABSTRACT FROM AUTHOR]

Anodic oxides were grown to 50 V on Ta-Nb sputtering deposited alloys, with high Nb content, in acetate ions containing an aqueous solution to study the effect of the anodizing bath composition on anodic layers' dielectric properties. Photoelectrochemical measurements proved the presence of a photocurrent in the band gap of photon energy lower than oxides, due to optical transitions involving localized electronic states as a consequence of acetate ions incorporation. Flat band potential value estimates assessed the insulating nature of the anodic oxides grown in the acetate buffer solution. Differential capacitance measurements showed that the highest capacitance value was measured for the sample grown on Ta-66%Nb. This capacitance value was higher with respect to those estimated for pure Ta and pure Nb anodic layers and with respect to the same alloy anodized in NaOH solution, i.e., acetate-free anodizing bath. [ABSTRACT FROM AUTHOR]

Mixed Ni-Al oxide catalytic precursors with different elemental ratios (20, 50, and 80 wt.% Ni0) were synthesized using green supercritical antisolvent co-precipitation (SAS). The obtained oxide precursors and metal catalysts were characterized in detail by X-ray diffraction (XRD) analysis, atomic pair distribution function (PDF) analysis, CO adsorption, and high-resolution transmission electron microscopy (HRTEM). It was found that the composition and structure of the Ni-Al precursors are related to the Ni content. The mixed Ni1−xAlxO oxide with NiO-based crystal structure was formed in the Ni-enriched sample, whereas the highly dispersed NiAl2O4 spinel was observed in the Al-enriched sample. The obtained metal catalysts were tested in the process of anisole H2-free hydrogenation. 2-PrOH was used as a hydrogen donor. The catalyst with 50 wt.% Ni0 demonstrated the highest activity in the hydrogenation process. [ABSTRACT FROM AUTHOR]

Copper was incorporated into the Ce-Sn and comparative Ce-Zr oxide supports by one-pot precipitation in the presence of CTAB template and by the impregnation of templated Ce-Sn and Ce-Zr oxides. The synthesized Cu-Ce-Sn and Cu-Ce-Zr catalysts were tested in the continuous-flow preferential oxidation of CO in hydrogen excess. The one-pot synthesized tin- and zirconium-doped catalysts demonstrated better CO conversion and CO2 selectivity than their impregnated counterparts. For the tin-modified ternary system that showed the best catalytic performance, the copper content was further optimized. The structure, reducibility, surface chemical state and textural properties of the catalysts were analyzed by SEM-EDX, XRD, H2-TPR, Raman spectroscopy, XPS and TEM. The nonmonotonic changes in the specific surface area, Cu+/Cu2+ ratio and ratio of lattice and non-lattice oxygen with increasing the Cu content are discussed in terms of copper distribution in the catalysts. The influence of the interaction between copper oxide species and the cerium–tin/cerium–zirconium oxide support on the performance of the ternary catalysts was thoroughly analyzed and discussed. [ABSTRACT FROM AUTHOR]

• In-situ characterization combined with ab-initio calculations for the determination of key intermediates and reactive sites. • The rate controlling step of 2Cl*→Cl 2 is facilitated by CuO (1 1 1), reducing the accumulation of Cl over CeO 2 and CeVO 4. • O 2 replenishing cycle was accelerated on CeO 2 and CeVO 4 , minimizing the evolution of the Cu-Cl bonding. The utilization of copper-based catalysts for converting by-product hydrogen chloride (HCl) into chlorine gas (Cl 2) offers a promising method for efficient management of HCl waste gas. However, a significant challenge in this process lies in catalyst deactivation, primarily attributed to the loss of active component in the form of Cu-Cl. In this study, we synthesized a Cu 2.4 CeV 0.5 O x catalyst that exhibited remarkable performance, achieving a space-time yield of 2.26 g Cl 2 /gcat*h with stable conversion efficiency at approximately 83 % maintained over 600 h. This level of stability represents a substantial improvement compared to previous studies of copper-based catalysts. In-situ DRFITS combined with ToF-SIMS confirms the reduction evolution of metal-Cl bonds. Additionally, ab-initio calculations elucidated that the rate-limiting step involves oxygen vacancy replenishment by O 2 rather than Cl over CeO 2 and CeVO 4 , thereby inhibiting Cu-Cl bond formation. This study introduces a novel approach for efficienct treatment of HCl waste gas, paving the way for its potential industrial application. [ABSTRACT FROM AUTHOR]

Suspension plasma spray (SPS) and solution precursor plasma spray (SPPS) are advanced thermal spraying techniques that enable creation of the coatings with desirable properties. In both techniques, it is necessary to entrain the liquid feedstock into the thermal jet so that it can be effectively transformed into oxide particles. In this study, the suspension containing 3wt.% solid load of 40 nm ZrO2-7%Y2O3 (7YSZ) powder with a medium of zirconium acetate-yttrium nitrate solution (instead of an aqueous or non-aqueous solvent) was used as titled solution medium suspension plasma spray (SMSPS) to produce the YSZ thermal barrier coating (TBC). The microstructure of SMSPS coating exhibited a columnar structure, with an inter-columnar spacing of approximately 5 microns. This columnar structure was attributed to the trajectory of nano-sized particles being affected by the plasma jet and their deposition at shallow angles on surface asperities, resulting in shadowing effect. The presence of vertical cracks within some of the columns in the microstructure of SMSPS coating was similar to the structure observed in SPPS coatings, highlighting the unique nature of this TBC structure. The oxidation testing at 1000°C for 12, 50, 120, and 250 hours revealed the formation of a thermally grown oxide (TGO) layer consisting of aluminum oxide and mixed oxides. The TGO layer growth rate was initially high, but then significantly decreased during the diffusion-controlled and steady-state stages of the test. It was found that the inter-columnar spacing in the coating facilitated oxygen diffusion, resulting in an accelerated oxidation of the bond coat during the initial stages. In addition, the SMSPS coating exhibited an average life of 753 cycles in 1-hours, 1000 ˚C thermal cycling test. The failure mechanism observed involved insular collapsing of adjacent clusters due to crack propagation which was attributed to the presence of vertical cracks and the columnar structure. [ABSTRACT FROM AUTHOR]

• In-situ characterization combined with ab-initio calculations for the determination of key intermediates and reactive sites. • The rate controlling step of 2Cl*→Cl 2 is facilitated by CuO (1 1 1), reducing the accumulation of Cl over CeO 2 and CeVO 4. • O 2 replenishing cycle was accelerated on CeO 2 and CeVO 4 , minimizing the evolution of the Cu-Cl bonding. The utilization of copper-based catalysts for converting by-product hydrogen chloride (HCl) into chlorine gas (Cl 2) offers a promising method for efficient management of HCl waste gas. However, a significant challenge in this process lies in catalyst deactivation, primarily attributed to the loss of active component in the form of Cu-Cl. In this study, we synthesized a Cu 2.4 CeV 0.5 O x catalyst that exhibited remarkable performance, achieving a space-time yield of 2.26 g Cl 2 /gcat*h with stable conversion efficiency at approximately 83 % maintained over 600 h. This level of stability represents a substantial improvement compared to previous studies of copper-based catalysts. In-situ DRFITS combined with ToF-SIMS confirms the reduction evolution of metal-Cl bonds. Additionally, ab-initio calculations elucidated that the rate-limiting step involves oxygen vacancy replenishment by O 2 rather than Cl over CeO 2 and CeVO 4 , thereby inhibiting Cu-Cl bond formation. This study introduces a novel approach for efficienct treatment of HCl waste gas, paving the way for its potential industrial application. [ABSTRACT FROM AUTHOR]

During the structural qualification testing of propellant tanks of a liquid engine, one M12 nut made of 35NCD16 steel used for the testing was found broken. Structural qualification testing was conducted to verify the design adequacy of tanks in human-rated missions. A detailed metallurgical investigation was conducted on the failed nut, bolt, and washers to determine the underlying cause of fracture. This investigation included detailed visual inspections, hardness testing, as well as microstructural characterization using tools such as the optical and scanning electron microscopy. In a comparative study, the nuts adjacent to and diametrically opposite from the failed assembly were examined along with exemplar nuts. Fractographic analysis revealed dimpled rupture characteristics with substantial inclusions in the longitudinal direction of the nut. A detailed investigation of the failed nut revealed long, aligned non-metallic inclusions, primarily mixed oxides of Mn, Si, and Cr. These inclusions were found to be the underlying cause of nut fracture below maximum tensile stresses. [ABSTRACT FROM AUTHOR]

[Display omitted] Thorium oxide is referred to as the world's nuclear fuel of the future for fourth-generation reactors, according to its numerous advantages. So, it is essential to provide practical solutions to improve thoria production technology. Recently, the oxalates co-precipitation method has received much attention as a wet method with many benefits, including reducing the production of radioactive dust and producing a homogeneous product. One of the significant advantages of this method is the possibility of precise control of the final oxide characteristics through the optimization of precipitation and heat treatment conditions. This study attempts to provide a complete report on the effect of multiple parameters of the oxalate precipitation and decomposition method, such as temperature, stirrer, and calcination, on the various properties of the final ThO 2 powder, including size, morphology, and surface area. In addition, the synthesis of (U-Th)O 2 fuels via oxalate co-precipitation and hydrothermal methods is investigated. [ABSTRACT FROM AUTHOR]

A series of clinoptilolite-supported catalysts, modified with hydrotalcite-like phase (HT) by co-precipitation, were prepared and tested in NH3-SCR reactions. It was found that deposition of HT on clinoptilolite increased conversion of NO within 250–450 °C, and that the positive impact on the catalytic activity was independent of HT loading. The promoting effect of clinoptilolite was attributed to Brönsted acid sites present in the zeolite, which facilitated adsorption and accumulation of ammonia during the catalytic process. Concentration of N2O in the post-reaction gas mixture reached its maximum at 300 °C and the by-product was most likely formed as a consequence of NH4NO3 decomposition or side reaction of NH3 oxidation in the high-temperature region. The gradual elimination of nitrous oxide, noticed as the material with the highest concentration of hydrotalcite phase, was attributed to the abundance of oligomeric iron species and the superior textural parameters of the material. UV-Vis experiments performed on the calcined samples indicated that Fe sites of higher nuclearity were generated by thermal decomposition of the hydrotalcite phase during the catalytic reaction. Therefore, calcination of the materials prior to the catalytic tests was not required to obtain satisfactory overall catalytic performance in NO reductions. [ABSTRACT FROM AUTHOR]

In this study, ternary mixed oxide catalysts containing Al2O3-MoO3-MgO and Al2O3-MoO3-WO3 were prepared with a changing ratio of MoO3:Al2O3 between 0.05 and 20.00. All catalysts showed 100% selectivity towards propene during the conversion of propan-2-ol at temperatures between 220 and 400 °C. The catalysts prepared from WO3 possessed very strong acid sites, which cause higher catalytic activity than catalysts prepared from MgO. Besides, the ratio of MoO3:Al2O3 was found to be directly proportional to the conversion yield for all catalysts. XRD results show that whole MgO reacted with Al2O3 and MoO3 to form amorphous MgMoO4 and MgAl2O4 phases during catalyst preparation. Furthermore, WO3 reacted only with Al2O3 to form Al2(WO4)3 and WO3 phase was also detected in the final product. The higher surface acidity and catalytic activity of Al2O3-MoO3-WO3 catalyst referred to this WO3 phase within the structure. [ABSTRACT FROM AUTHOR]

Copper vanadate (CV) and manganese vanadate (MV) exhibit magnetic and optical properties that have drawn the attention. Due to CV polymorphism and phase multiplicity, CV is common to exist as mixed phases. In this study, nanostructures of mixed-phase CVs mixed with MV were synthesized hydrothermally followed by calcination at 400 °C, with Mn mole fractions 0.0, 0.4, 0.6, 1.0. The uncalcined and calcined Mn-Cu vanadates (MCVs) were investigated by XRD, SEM, TEM, FT-IR, EDX, ICP-AES, TGA, DTA, DSC, BET, XPS, and VSM. XRD analysis shows co-existence of multi-phase CVs with MnV2O6 and V oxides. Electron micrographs show nanostructures of multiple morphologies (rods, cubes, sheets, and irregular). As Mn content increased in the MCVs, their thermal stability increased, optical bandgap (Eg) declined from 2.46 to 1.60 eV, and magnetism diverted from the superparamagnetic-like to paramagnetic (Hc from 1362 to 69 G and Mr/Ms from 0.430 to 0.003). Magnetism parameters of calcined MCVs were more labile to Mn content variation compared to the uncalcined MCV counterparts. [ABSTRACT FROM AUTHOR]

2,4-Dichlorophenol (2,4-DCP) is a persistent organic compound present in many water reservoirs for human consumption, generating a high risk for all species, especially for humans due to its toxicity. In this work, Mg/Al = 2, 3 and 4 layered double hydroxides activated at 450 °C are presented for the formation of photocatalysts formed by the mixture of MgO–MgAl2O4 oxides for the photocatalytic degradation of 2,4-DCP in aqueous solution in a UV irradiated reaction system. The results showed a good photocatalytic activity by achieving a complete degradation of 2,4-DCP up to mineralization. The high degradation capacity of 2,4-DCP is attributed to the presence of holes in these materials that promote the formation of hydroxyl radicals (OH⋅) and superoxide radicals (O2⋅−) in only 30 min of reaction time. [ABSTRACT FROM AUTHOR]

In the present study, the influence of adding cerium oxide to NiMo/Al2O3 hydrodesulfurization (HDS) catalysts was herein analyzed through the impregnation of cerium sulfate at the surface of an Al2O3 support obtained by a sol–gel method at two different Ce contents (1 and 5 mol% as CeO2). The cerium-containing Al2O3 supports were then impregnated with Ni(NO3)2 and (NH4)6Mo7O24 precursors in aqueous solutions at pH 7 or pH 9 before being dried at 120 °C for 4 h and finally calcined under air at 400 °C for 4 h. The as-obtained NiMo/Ce–Al2O3 catalysts were characterized at their oxide state using UV–Vis diffuse reflectance, Raman and Infrared spectroscopies after each preparation step. Catalysts were also characterized at the sulfide state by pyridine adsorption followed by infrared spectroscopy. The sulfide catalysts were then evaluated in the hydrodesulfurization of dibenzothiophene (DBT). Results show that the pH of impregnation used influences more the final HDS activity than the amount of Ce with an optimum observed using 1 mol % and a pH of impregnation of 9. The activity achieved is then 62% higher than for a NiMo/Al2O3 reference catalyst. The analysis of both Raman and UV–Vis spectroscopy results show that impregnation under basic conditions help to maximize the dispersion of the CeO2 phase onto the alumina support improving substantially the final HDS activity. [ABSTRACT FROM AUTHOR]

Surfactant addition during support synthesis resulted in materials with defined porosity, smaller particle size, and the absence of segregated ZrO2 and TiO2 crystalline phases at least to the XRD detection limit. The data obtained by N2 physisorption showed improved textural properties compared with the individual pure oxides. The Ultraviolet–visible (UV–Vis) diffuse spectroscopy revealed broadband assigned to the mixed-phase. Meanwhile, the micrographs obtained by transmission electron microscopy showed nanometric domains of crystallinity and a worm-like morphology in all the samples. Raman spectroscopy showed the possible formation of the TiZrO4 forming the mixed oxides support. The chemical analysis performed by ICP-OES corroborates the expected equimolar relation Zr/Ti and the atomic ratio Ni/(Ni + W) approximately equal to 0.31. The support properties intrinsically influenced the WS2 nano slabs, as observed by TEM micrographs for the NiW/ZT-x sulfided series. The XPS analysis revealed that sulfidation degree increases and the highest amount of NiWS phase among all the materials are observed when the NiW system is deposited on the mixed oxides prepared with pluronic. The latter was also related to the reaction rates, where the sulfided NiW/ZT-x catalysts presented higher values than the NiW/ZT reference material. NiW/ZT-P sulfided sample showed the maximum reaction rate among the series studied. [ABSTRACT FROM AUTHOR]

This paper presents synthesis hydrothermal-assisted microwave method at low temperature of NiTiO3/ZnO for photocatalytic and sonophotocatalytic degradation of rhodamine B dye. XRD patterns revealed the presence pure phases of the materials, whereas morphology by SEM clearly indicates the presence of hexagonal nanorods-prisms of ZnO mixed with agglomerated particles of NiTiO3. Photocatalysts showed energy band gap values between 2.2 and 2.9 eV allowing their activation under visible light irradiation. PL curves corroborated that NiTiO3/ZnO with 90:10 ratio is the one that presented the lowest intensity indicating higher active site generation and lower electron-hole pair recombination. Results of sonophotocatalytic activity achieved almost 95% dye degradation in 120 min for NiTiO3/ZnO (90:10), while the pure oxides degraded up to 74%. Obtaining a 35% increase in efficiency and increasing the reaction rate up to 4 times compared to photocatalytic tests. FTIR analyses show the decomposition of the molecule by sonophotocatalysis which favors the breaking of C-C, C-O and C-N bonds. In conclusion, synthesis of NiTiO3/ZnO achieved a synergy between both oxides, enhanced the electron-hole separation due to heterojunction between both semiconductors, which during sonophotocatalytic processes favored the formation of more reactive radicals. Therefore, NiTiO3/ZnO oxides can be considered as active materials for application in photoinduced processes. [ABSTRACT FROM AUTHOR]

An environmentally friendly and safe synthesis of phloroglucinol and its derivatives through the flow hydrogenation of 1,3,5-trinitrobenzenes on heterogeneous copper catalysts is reported. It was found that hydrogenation of 1,3,5-trinitrobenzene, 2,4,6-trinitrotoluene, 2,4,6-trinitroxylene, and 2,4,6-trinitromesitylene in methanol over Cu–Al mixed oxides derived from layered double hydroxides led to selective formation of the corresponding triaminobenzenes, which were isolated from the reaction mixture in the form of double salts with sulfuric acid and were stable in storage. Subsequent hydrolysis in aqueous solution gave the phloroglucinol derivatives in good yields (75–82%). [ABSTRACT FROM AUTHOR]

In this study, V2O5/ZrO2 samples loaded with different wt% of V2O5, ranging between 0% and 20% (wt% = 2.5, 3.6, 7.5, 10, and 20), were prepared and studied in the dehydrogenation of 2-butanol in order to investigate their acid-basic properties and to select the most interesting sample, that was identified in the 3.6 wt%V2O5/ZrO2. Such a catalyst was modified by adding phosphate at different atomic ratios (P/V = 0.5, 1, and 2) and further characterized by XRD, SEM-EDX, ESR, UV-Vis-PIR diffuse reflectance. Tests of catalytic dehydrogenation of 2-butanol were also performed. Then, the so-prepared samples were investigated in the oxidative dehydrogenation (ODH) of propane that represents the reaction of main interest in this study. It has been shown that the introduction of 3.6 wt%V2O5 and phosphate in the zirconia matrix enhances the stability of the tetragonal structure, improves acidity, and promotes ODH activity. Compared to the unpromoted 3.6 wt%V2O5/ZrO2 catalyst, the addition of phosphate increases the overall propane conversion from 12% to 20%, and also the propylene selectivity from 54% to near 64%, in the experimental conditions F °C3H8/F°O2/F°total (cm3/min): 3.6/1.8/60 at the temperature of 500 °C. The influence of the reaction mixture on the ODH, in particular the oxygen flow rate, was addressed. Highlights: Phosphorus loaded V2O5/ZrO2 catalysts were prepared and investigated in the oxidative dehydrogenation of propane. Addition of V2O5 and phosphorus to ZrO2 stabilized the tetragonal phase with respect to the monoclinic one. Among the prepared V2O5/ZrO2 samples, the most active catalyst corresponds to 3.6 wt% of V2O5/ ZrO2, The addition of phosphorus to 3.6 wt% V2O5/ZrO2 improves acidity and selectivity to propylene. Correlation between catalysts acidity and oxidative dehydrogenation of propane was observed. [ABSTRACT FROM AUTHOR]

Silica, titania, and mixed silica–titania powders have been used as supports for loading 5 wt% Cu, 5 wt% Ag, and 2.5 wt% Cu-2.5 wt% Ag with the aim of providing a series of nanomaterials with antifouling properties. All the solids were easily prepared by the wetness-impregnation method from commercially available chemical precursors. The resulting materials were characterized by several techniques such as X-ray diffraction analysis, X-ray photoelectron spectroscopy, N2 physisorption, and temperature-programmed reduction measurements. Four selected Cu and Ag SiO2- and TiO2-supported powders were tested as fillers for the preparation of marine antifouling coatings and complex viscosity measurements. Titania-based coatings showed better adhesion than silica-based coatings and the commercial topcoat. The addition of fillers enhances the resin viscosity, suggesting better workability of titania-based coatings than silica-based ones. The ecotoxicological performance of the powders was evaluated by Microtox luminescence tests, using the marine luminescent bacterium Vibrio fisheri. Further investigations of the microbiological activity of such materials were carried out focusing on the bacterial growth of Pseudoalteromonas sp., Alteromonas sp., and Pseudomonas sp. through measurements of optical density at 600 nm (OD600nm). [ABSTRACT FROM AUTHOR]

The Phase, microstructural and dielectric properties of Ba1-xSrxTi4O9 (0 ≤ x ≤ 0.8) ceramics were investigated. The XRD analysis revealed the formation of orthorhombic structured (Pnmm) BaTi4O9 phase. The XRD peaks were observed to shift towards the lower 2θ values with increasing Sr2+ contents which may be attributed to the substitution of relatively larger cation of Sr2+ (RSr = 1.61 Å) for Ba2+ (RBa = 1.44 Å) in BaTi4O9. The dielectric constant (εr) increased with Sr2+ substitution from 22 to 122 at 1MHz. The maximum value of the dielectric loss was observed 0.11922 for x = 0.8 at 1 MHz. [ABSTRACT FROM AUTHOR]

Bio-oil derived from the pyrolysis of lignocellulosic biomass residues cannot be used directly as biofuel due to the high content of oxygenated compounds. As an alternative, bio-oil must undergo a deoxygenation process, such as catalytic hydrodeoxygenation (HDO). In this sense, this work studied the effect of different concentrations of Ce3+ and Ce4+ in layered double hydroxides (LDHs) in order to obtain mixed oxide catalysts containing NiAlCe (NiO-NiAl 2 O 4 -CeO 2) with low cost and high performance for the hydrodeoxygenation of anisole as a model bio-oil compound. Mixed oxides were obtained from the thermal decomposition of layered double hydroxides (LDHs) by using terephthalic acid as compensation anion, with molar ratio: Ni2+/(Al3++ M) = 1.0, where M = Ce3+; Ce4+ or Ce3+-Ce4+; and Al/Ce ratios of 9 and 1. Characterization analyses confirmed the formation of LDHs for all materials, although at lower Al/Ce ratio it is observed a loss of crystallinity, due to a greater repulsion and distortion of the layer structure caused by the incorporation, in greater amount, of cations with a high ionic radius. The increase in the content of cerium in mixed oxides also led to an increase in the acidity of the catalysts, in addition to a reduction in the surface area, justified by the pore blockage by CeO 2 on the catalyst surface. The greater structural and thermal stability was evidenced in the LDHs derived from Ce4+, as well as a greater dispersion of the NiO phase in the corresponding mixed oxides, and therefore presenting greater anisole conversion. The obtained data indicated that the presence of Ce4+ ions on the catalyst surface was decisive in the conversion of anisole to cyclohexane, the main deoxygenated product, obtained via the direct deoxygenation and hydrogenation mechanism. [Display omitted] • Mixed oxide (NiAlCe) prepared from layered double hydroxides (LDHs) are effective catalysts in HDO reactions. • Cerium oxidation state used during synthesis determined the textural properties as well as the catalytic activity. • Catalyst prepared from Ce4+ were more active and stable catalyst. • LDH stability and active phase dispersion explain the catalytic behaviour. [ABSTRACT FROM AUTHOR]

Reactive flash sintering (RFS) is a method that was recently developed to produce dense single‐phase bulk ceramic parts through solid‐state reactions in a single‐step that only takes a few minutes. The influence of the RFS parameters on the phase purity of a simple mixed oxide, (Zr0.8,Ce0.2)O2, was investigated. Parameters such as furnace temperature, furnace atmosphere, electric current density, and alternating current (AC) or direct current (DC) were examined. It was found that (Zr0.8,Ce0.2)O2 pellets with high densities, above 90% of its theoretical density, can be produced by RFS in a few minutes when RFS occurs under oxidizing atmospheres, AC fields with current densities of 100 mA·mm−2, and at a furnace temperature of 1200°C. Reducing conditions such as Ar‐H2 atmosphere and DC fields, low furnace temperatures, and low current densities resulted in phase impurities and poor reactions between the ZrO2 and the CeO2 powders. These results show that RFS is a useful method to produce mixed oxides, but it is very sensitive to the processing parameters. This is the first time that the influence of most of the RFS processing parameters has been studied systematically. Thus, the present work aims to provide guidelines on selecting the right processing parameters when exploring RFS. [ABSTRACT FROM AUTHOR]

Recently, catalysts with hydrotalcites and hydrotalcite-derived compounds have attracted particular interest due to their specific properties, mostly well-developed texture, high thermal stability, and favorable acid–base properties. In this work, we report the investigation of ammonia synthesis on barium-promoted cobalt catalysts supported on hydrotalcite-derived Mg-Al mixed oxides with different Mg/Al molar ratios. The obtained catalysts were characterized using TGA-MS, nitrogen physisorption, XRPD, TEM, STEM-EDX, H2-TPD, CO2-TPD, and tested in ammonia synthesis (470 °C, 6.3 MPa, H2/N2 = 3). The studies revealed that the prepared Mg-Al mixed oxides are good candidates as support materials for Co-based catalysts. However, interestingly, the support composition does not influence the activity of Ba/Co/Mg-Al catalysts. The change in Mg/Al molar ratio in the range of 2–5 did not significantly change the catalyst properties. All the catalysts are characterized by similar textural, structural, and chemisorption properties. The similar density of basic sites on the surface of the studied catalysts was reflected in their comparable performance in ammonia synthesis. [ABSTRACT FROM AUTHOR]