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In this study, we synthesized cobalt-doped molybdenum supported on silica (Co/MS) nanocomposites with varying concentrations of cobalt (1, 5, 10, 15, and 20 wt%) using the sol-gel method. We investigated their physico-chemical properties, photocatalytic activity, and antimicrobial efficacy. The synthesized nanocomposites were characterized using a range of techniques, including X-ray powder diffraction (XRD) to determine crystal structure, UV-vis spectroscopy for optical properties, Fourier transform infrared spectroscopy (FTIR) for functional group analysis, and scanning electron microscopy coupled with energydispersive X-ray microanalysis (SEM-EDX) for morphological and elemental composition analysis. The photocatalytic performance of these catalysts was assessed by their ability to degrade organic dyes, specifically methyl orange and methylene blue, under visible light irradiation. Our results demonstrated that the photocatalytic efficiency increased with higher cobalt content, with the 20 wt% Co/MS nanocomposite showing the highest degradation rates. Additionally, we evaluated the antibacterial activity of the nanocomposites against a range of microorganisms, including Gram-positive and Gram-negative bacteria, as well as fungal species. The 20 wt% Co/MS nanocomposite exhibited superior antimicrobial activity compared to the other samples, indicating its potential for applications in environmental remediation and antimicrobial treatments. [ABSTRACT FROM AUTHOR]

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This study examines the feasibility of utilizing mixed-oxide fuel [(U0.9, rgPu0.1) O2] instead of traditional UO2 in nuclear reactors. The utilization of (U0.9, rgPu0.1) O2 is particularly significant as it represents an effective approach to nuclear fuel recycling by combining reactor-grade plutonium extracted from partially used nuclear fuel and depleted uranium obtained through the enrichment process. The fundamental neutronic characteristics, such as the radial power distribution, were investigated using the MCNPX 2.7 algorithm to identify the specific channel for subsequent thermal-hydraulic (TH) analysis. The TH analysis was conducted using COMSOL-Multiphysics, allowing for the estimation of the fuel rod's axial and radial temperature profiles, as well as the determination of the departure from the nucleate boiling ratio. Furthermore, the coupling between heat transfer and solid structure (SS) was achieved using the Multiphysics tool in COMSOL-Multiphysics. This coupling facilitated the simulation of key SS parameters, including von Mises stress, volumetric strain, and displacement, while considering the influence of heat transfer. The results demonstrate significant improvements and enhanced safety margins when utilizing (U0.9, rgPu0.1) O2. [ABSTRACT FROM AUTHOR]

Capsicum annuum L. var. "Chile de árbol" combined with poly(lactic-co-glycolic acid) (PLGA) and TiO2-ZnO oxides synthesized at different molar ratios and pH (Ti-Zn A and B 3:1, 1:1, and 1:3) via the sol-gel method was characterized by the Brunauer–Emmett–Teller (BET) method, a UV-Vis spectrophotometer (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), High-Performance Liquid Chromatography (HPLC-DAD), and a release profile through mathematical models to explain its behavior. Furthermore, FTIR revealed the presence of PLGA, TiO2, and ZnO as well as amino group characteristics from oleoresin components, principally alkaloid groups (capsaicin and dihydrocapsaicin), as evidenced by HPLC, to identify the presence of capsaicin and dihydrocapsaicin. The UV-Vis spectra showed a slight hypsochromic shift in the PLGA treatments. The release profile demonstrated a higher controllable release in the PLGA treatments than in the double nanoemulsions. Moreover, it is important to note that the effect of NPs influenced the release profile itself, increasing the release when NPs were synthesized at an acidic pH. Therefore, the TiZnOl/PLGA A characteristics suggest that these results have potential for pharmaceutical (as drug carriers) and medical applications. [ABSTRACT FROM AUTHOR]

The development of catalytic methods for xylose transformation as renewable raw material into value-added chemicals such as lactic and glycolic acid esters has been the subject of intensive research in recent years. Thus, methyl lactate and methyl glycolate are used as a starting material for the production of lactide and glycolide – an important monomers for the production of biodegradable polymers. The aim of this work was to search of simple effective catalyst for transformation of xylose into methyl esters of lactic and glycolic acids. For this purpose, tin-containing alumina doped with СeO2, MoO3 and CuO oxides were synthesized by impregnation method. Textural and structural parameters of obtained МeO‑SnO2/Al2O3 mixed oxides were estimated from the results of low-temperature adsorption-desorption of nitrogen and X-ray diffraction. The formation of morphology ceria close to octahedra for CeО2‑SnO2/Al2O3 sample is confirmed by the X-ray phase analysis data and SEM microphotographs. The UV spectroscopy data indicates the nanosize of tin dioxide particles on the γ‑Al2O3 surface. According to the titration results, CeО2‑SnO2/Al2O3 is acid mixed oxide with H0 ≤ –3.0. The catalytic conversion of xylose solution in methanol was carried out in rotated autoclaves and in a flow stainless steel reactor with a fixed bed of catalyst. The products of the target reaction C5H10O5+2CH3OH+1/2O2 = C4H8O3+C3H6O3+2H2O were analyzed by 13C NMR. It was found that a complete conversion of 4 % xylose solution in a 70 % aqueous methanol solution occurs with the formation of methyl lactate (42 %) and methyl glycolate (24 %) on the developed CeO2-SnO2/Al2O3 catalyst loading of 3.5 mmol C5H10O5/gcat/h at 190 °C/3.0 MPa in air flow. The path of the reaction is proposed, namely: the IVSn4+ ions in           CeO2-SnO2/Al2O3 catalyst as Lewis acid sites promote retro-aldol xylose condensation and further Cannizzaro rearrangement of intermediate methyl pyruval hemiacetal into methyl lactate. And CeO2 provides selective oxidation of glycol aldehyde formed as a result of aldol decondensation of xylose to methyl glycolate. [ABSTRACT FROM AUTHOR]

Indoor air pollution is comprised of fine particles, bacteria, fungi, and hydrocarbons. Acceptable indoor air quality is maintained using several layers of air filters. Alternative materials with the capacity to remove CO2 from indoor air with antibacterial efficacy need to be further investigated. Mixed oxides of Ce1.0-xCuxO (x = 0.0, 0.1, 0.5, 0.9, 1.0) were synthesized using a co-precipitation method. Characterization studies revealed that single oxides of Ce1.0O and Cu1.0O were of cubic fluorite and monoclinic crystal structures, respectively. Results also show that Ce0.1Cu0.9O and Ce0.5Cu0.5O were composites. All samples were classified as mesoporous materials with a type IV isotherm, and the main functional group was identified as Ce–O–Cu. The surface area of Ce0.5Cu0.5O was 17.63 m2/g. The highest CO2 adsorption capacity was 5.72 cm3/g for Ce0.5Cu0.5O. Moreover, the greatest antibacterial activity against B. subtilis (12.22 mm inhibition zone) and P. aeruginosa (7.34 mm inhibition zone) was observed for Ce0.5Cu0.5O at a 30 mg/L concentration. The synthesis of mixed Ce1.0-xCuxO oxides along with their satisfactory antibacterial performance and CO2 adsorption capacity, indicate its potential use as an alternative material for inclusion in indoor air filters.

In this review, we discuss liquid–phase redox reactions using oxide solid–solution catalysts. These oxide solid solutions are readily prepared by introducing various elements into the foundational metal oxide template. Doping with metal species leads to the formation of [MOx] clusters with unique coordination structures, which is a remarkable feature that deserves attention. Consequently, oxide solid solutions exhibit catalytic capabilities that extend beyond those of conventional metal–oxide catalysts. Notably, these [MOx] clusters occasionally exhibit exceptional redox activities that can be used to catalyze liquid–phase redox reactions. Hence, we conjecture that a connection exists between catalyst structure and activity. This review delves into oxide solid–solution catalysts through the lenses of organic chemistry, solid catalysts, and computational chemistry, thereby collectively shaping our understanding and prospects in this field. [ABSTRACT FROM AUTHOR]

In this study, vermiculite was explored as a support material for nickel catalysts in two key processes in syngas production: dry reforming of methane with CO2 and steam reforming of ethanol. The vermiculite underwent acid or base treatment, followed by the preparation of Ni catalysts through incipient wetness impregnation. Characterization was conducted using various techniques, including X-ray diffraction (XRD), SEM–EDS, FTIR, and temperature-programmed reduction (H2-TPR). TG-TD analyses were performed to assess the formation of carbon deposits on spent catalysts. The Ni-based catalysts were used in reaction tests without a reduction pre-treatment. Initially, raw vermiculite-supported nickel showed limited catalytic activity in the dry reforming of methane. After acid (Ni/VTA) or base (Ni/VTB) treatment, vermiculite proved to be an effective support for nickel catalysts that displayed outstanding performance, achieving high methane conversion and hydrogen yield. The acidic treatment improved the reduction of nickel species and reduced carbon deposition, outperforming the Ni over alkali treated support. The prepared catalysts were also evaluated in ethanol steam reforming under various conditions including temperature, water/ethanol ratio, and space velocity, with acid-treated catalysts confirming the best performance. [ABSTRACT FROM AUTHOR]

The 3D photoelectrochemical cell was developed with epoxy resin and a working composite electrode produced with a blend of 3D printer commercial conductive filament of polylactic acid biopolymer and carbon black (PLA/CB) mixed with silica/tungsten (VI) oxide (SiO2/WO3) synthesized was used for the determination of imidacloprid in water samples. Imidacloprid is a neonicotinoid pesticide considered potentially neurotoxic, and investigating its presence in aquatic environments is of great importance. The PLA/CB/SiO2/WO3 sensor was morphologically characterized by scanning electron microscopy. Photoelectrochemical performance of the composite sensor was evaluated by chronoamperometry, electrochemical impedance spectroscopy and cyclic voltammetry. In the presence of light (on) using differential pulse voltammetry in borate buffer solution (0.1 mol L−1, pH 7.0), the modified sensor exhibited a linear range of 0.15–93.70 μmol L−1 and with a limit of detection of 0.04 μmol L−1 to determine imidacloprid. The modified sensor did not present interferences for K+ and Fe3+ ions, carbendazim, glyphosate and thiamethoxam pesticides. Furthermore, the recovery in spiked samples successfully determined the presence of imidacloprid pesticide in tap water and natural river surface water. [ABSTRACT FROM AUTHOR]

CeO2–MnOx mixed oxides supported on different carriers (ZSM-5, TiO2, and SAPO-34) were prepared by the sol-gel combustion method and evaluated for the selective catalytic reduction of NO with NH3. The physicochemical properties of the samples were determined by using XRD, TEM, N2 adsorption (BET method), H2-TPR, and NH3-TPD. The Ce–Mn/TiO2 exhibited a higher NO conversion than Ce–Mn/ZSM-5 in the 100-200°C temperature range, but the NO conversion of Ce–Mn/ZSM-5 increases with reaction temperature (being the N2 selectivity close to 100%) whereas, for Ce–Mn/TiO2, the N2 selectivity extremely decreases. The reducibility and surface acidity of samples seems to explain the catalytic performance. Thus, although the reducibility of Ce–Mn/ZSM-5 and Ce–Mn/TiO2 was similar, the large number of surface acid sites of Ce–Mn/ZSM-5 could be a plausible reason for its excellent SCR activity. In fact, the superior SCR activity of Ce–Mn/ZSM-5 (94% NO conversion and 95% N2 selectivity at 300°C) is related to the presence of well-dispersed Ce–Mn mixed oxide nanoparticles, high reducibility, and a large number of surface acid sites. [ABSTRACT FROM AUTHOR]

3D nanostructured Prussian blue analogues (PBA) are promising candidates in the family of metal-organic frameworks (MOFs) for applications as bifunctional electrocatalysts due to their open framework structures, high specific surface areas and variable metal active sites. Due to their facile synthesis approach and unique framework structures, these nanostructures can be easily transformed into different structures/materials having different compositions. Herein, we have synthesized Ni–Fe Prussian blue analogue nanocubes (NiFe-PBA-NC) via a simple precipitation method and converted them into Ni–Fe Prussian blue analogue nanocages (NiFe-PBA-NG) and porous mixed metal oxide (NiFe-oxide). For the conversion of nanocubes to nanocages a very controlled etching process is carried out by using an ammonia solution while for the formation of porous mixed metal oxide, nanocubes are annealed in the presence of air. The transformation of nanocubes to nanocages and mixed metal-oxide is thoroughly characterized by various spectroscopic and microscopic techniques and employed as a bifunctional electrocatalyst for oxygen evolution and oxygen reduction reactions (OER and ORR, respectively) in which NiFe-oxide proved to be the best bifunctional catalyst. This thorough and systematic study reveals the fundamentals of the structure-property co-relation towards engineering novel bifunctional electrocatalysts. • Synthesis of NiFe-PBA-NC nanocubes and their conversion into nanocages and NiFe-oxide. • The prepared catalysts were characterized by XRD, FT-IR, XPS, TGA and FE-SEM techniques. • Investigation of role of morphology on oxygen evolution reaction (OER) and oxygen reduction reactions (ORR). • The Prepared catalysts were employed as bifunctional catalysts for OER and ORR in basic medium. • NiFe-oxide exhibit enhanced catalytic activity due to high electrochemical surface area. [ABSTRACT FROM AUTHOR]

Preparation of biodiesel by commonly used homogeneous transesterification produces a large amount of wastewater as well as other disadvantages like soap formation, difficult separation, dirty glycerin, and limitation of homogeneous catalyst used by the content of free fatty acids. The paper focuses on testing mixed oxide catalyst (La-Ni/MgAl) in a two-stage transesterification on various types of oils as sources for biodiesel preparation. The tested oils include commercial sunflower and corn oil, hemp oil (commonly used in cosmetics), oil extracted from spent coffee grounds, and non-food oil derived from the Camelina sativa (L.) Crantz plant. Heterogeneous transesterification offers cleaner products, easier separation, and the possibility of reusing catalysts. La-Ni/MgAl mixed oxide was obtained from hydrotalcite, prepared by co-precipitation. The novelty of this study lies in comparing the transesterification process using different types of oils and evaluating the impact of their composition on catalyst activity. In addition, a unique feature of this study is the incorporation of a two-stage transesterification process, which allows for the reaction of any unreacted oil and achieves a content of FAME in biodiesel that meets European standards. The results showed that using two-stage transesterification with mixed oxides can achieve a FAME content higher than 98 % for all tested oils. [ABSTRACT FROM AUTHOR]

In this study, vermiculite was explored as a support material for nickel catalysts in two key processes in syngas production: dry reforming of methane with CO2 and steam reforming of ethanol. The vermiculite underwent acid or base treatment, followed by the preparation of Ni catalysts through incipient wetness impregnation. Characterization was conducted using various techniques, including X-ray diffraction (XRD), SEM–EDS, FTIR, and temperature-programmed reduction (H2-TPR). TG-TD analyses were performed to assess the formation of carbon deposits on spent catalysts. The Ni-based catalysts were used in reaction tests without a reduction pre-treatment. Initially, raw vermiculite-supported nickel showed limited catalytic activity in the dry reforming of methane. After acid (Ni/VTA) or base (Ni/VTB) treatment, vermiculite proved to be an effective support for nickel catalysts that displayed outstanding performance, achieving high methane conversion and hydrogen yield. The acidic treatment improved the reduction of nickel species and reduced carbon deposition, outperforming the Ni over alkali treated support. The prepared catalysts were also evaluated in ethanol steam reforming under various conditions including temperature, water/ethanol ratio, and space velocity, with acid-treated catalysts confirming the best performance.

The development of alternative (and free-of-antibiotics) antibacterial and antibiofilm agents is an important strategy to circumvent the resistance of bacteria to antibiotics. Herein, we explore the production of mixed oxides by incorporating silver nanoparticles in titanium dioxide as a silver concentration-dependent antibacterial agent that is further incorporated in Tilapia fish skin (a promising prototype of xenograft), integrating the antibacterial activity of mixed oxide into the intrinsic properties of Tilapia skin. The antibiofilm activity of samples prepared with high concentrations of silver (10 wt% of precursor AgNO3) has been considered a good antibiofilm response. The influence of silver content is also observed with respect to the minimum bactericidal concentration, which is reduced to 3.13 mg/mL with a characteristic kill time in the order of 30 min that is associated with antibiofilm activity in biofilm-forming strains of Staphylococcus aureus. These results indicate that modified Tilapia fish skin acquires antibacterial behavior and can be explored for xenografts with prospective applications in the light-dependent actuation of TiO2-based compounds.

Mixed solid oxides are known for their excellent catalytic property and applications in environmental remediation. This study presents a green-synthesis route for magnesium oxide-titanium oxide, a mixed oxide demonstrated to possess high performance of phenol removal from hydrocarbon refinery process wastewater. Mixed oxide (MgO-TiO2) was prepared by using the whole extract from leaves of Piliostigma Thonningii as a reducing agent. A structural attribute of the mixed oxide was investigated using X-ray Diffractometer, HighResolution Scanning Electronic Microscopy and Energy Dispersive X-ray. Petroleum refinery raw wastewater having a phenol concentration of 19.961 mg/L was treated using green-synthesized mixed oxide. Adsorptive phenols removal up to 99.5% was achieved with a dosage of 0.04 g/100 mL at a temperature of 35 °C, and a contact time of 1.167 h. By this, the treated water meets the standard acceptable phenol concentration (0.1 mg/L) in wastewater of hydrocarbon refinery. [ABSTRACT FROM AUTHOR]

Magnesium–aluminum layered double hydroxides and mixed oxides based on them were obtained by high and low supersaturation methods and analyzed. It was shown that the phase composition and formation of nano-sized particles with a large surface area is significantly affected by the rate of introduction of magnesium–aluminum systems into the medium of the precipitated material. All of the obtained samples were studied by thermogravimetric analysis with mass-spectrometric detection, X-ray diffractometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and infrared spectroscopy. [ABSTRACT FROM AUTHOR]

An efficient organic/inorganic magnetic nanohybrid of MgAl@CuFe2O4-polylysine was successfully synthesized and employed as a suitable adsorbent for removal Cr(VI) and methyl orange from water solution. The prepared nanohybrid was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometer and thermogravimetric analysis. The nanohybrid of MgAl@CuFe2O4-polylysine was employed to adsorb anionic species, i.e., Cr(VI) and methyl orange through electrostatic attraction, ligand exchange and ion exchange. Multivariate optimization with Box-Behnken design was used to evaluate effective parameters such as dosage of adsorbent, solution pH and contact time on adsorption and their interaction. Results showed that pH, contact time and adsorbent dosage are effective parameters for Cr(VI) adsorption; however, the pH of the solution is the sole effective parameter for methyl orange adsorption. Both analyte adsorptions are fast with adsorption times less than 15 min. Isotherm study revealed that the prepared nanohybrid is a highly efficient adsorbent for methyl orange and Cr(VI) with adsorption capacity of 693.6 and 281.8 mg g−1, respectively. Isotherm study showed that adsorption of both analytes well fitted with the Freundlich adsorption isotherm model, which indicated multilayer adsorption on the heterogeneous surface. The magnetic saturation for the prepared adsorbent was 12.64 emu g−1, which was adequate and suitable for magnetic separation of samples. The prepared adsorbent was regenerated using ethanol-aquaeous NaOH solution as it shows 90% removal efficiency after three cycles. [ABSTRACT FROM AUTHOR]

This study focus on modification of TiO2 with a mixture of SnO2 and CeO2 that can actively degrade methylene blue as industrial dye under visible light. The synthesis of mixed oxides SnO2/CeO2/TiO2 was carried out by the precipitation method which included dissolving the reactants using HNO3 and re-precipitation with NaOH solution. The precipitate was then dried and calcined at 650 °C. The calcined products were characterized by XRD, DRUV, FTIR, SEM-EDX, TEM, and photoluminescence spectroscopy. The addition of both SnO2 and CeO2 can decrease the bandgap of TiO2 and inhibit the recombination process. The results showed that the photodegradation of MB under visible light using mixed oxides SnO2/CeO2/TiO2 was higher than that of TiO2, SnO2, and CeO2. The preparation of mixed oxides SnO2/CeO2/TiO2 using Sn/Ce ratio of 1:1 showed the highest photodegradation of MB up to 87%. The optimum conditions for the photodegradation of 40 ppm of MB were obtained at pH 7, with 0.2 g of catalyst mass, and 120 min of reaction time. The photocatalytic mechanism of the SnO2/CeO2/TiO2 mixed oxides was obtained up to three runs without appreciable loss of activity and shows great potential to be an excellent candidate for environmental remediation.

In this work, anodic oxidation of Ti-40 wt.% Zr alloy in EG/NH4F/H2O electrolyte was done to produce anodic self-aligned oxide nanotube arrays. The nanotubes were amorphous but upon annealing at 400° C they were crystallized into ZrO2–TiO2 nanotubes and ZrTiO4–TiO2 nanotubes at 600 °C. The nanotubes were used to reduce 60 ppm Cr(VI) ions under sunlight or UV irradiation. 100% removal of Cr(VI) was achieved on ZrTiO4–TiO2 nanotubes after 5 h of exposure to UV light but only 53% removal was obtained on ZrO2–TiO2 nanotubes. The higher photocatalytic activity of the ZrTiO4–TiO2 nanotubes can be related to the presence of the ZrTiO4 phase which has good acid–base properties as well as the junction formation between ZrTiO4 and TiO2 that can further enhance the reduction process.

Developing highly active catalyst for oxygen evolution reaction (OER) with low noble metal loading is crucial for the application of proton exchange membrane (PEM) water electrolysis. Ir-transition metal (TM) binary catalyst with chemical leaching was reported to perform excellent activity with TM leaching. However, most of the studies on the activation-decay focused on the final status, and the variation process remains unclear. With cysteamine·HCl, a modified facile molten salt method was applied to prepared highly active Ir–Ni mixed oxide (c-xNiIrMO), which perform 5.5 times higher mass activity than commercial IrO 2. The variation of active surface area, intrinsic activity, conductivity of prepared catalyst layer during the activation process are studied to unveil the key factors for the activity enhancement. With further stability test, c-xNiIrMO with Ni content lower than 67% performs decrease intrinsic activity and improved kinetic performance in the first hundred cycles. After obtaining a stable Ir 0.95 Ni 0.05 O x structure, further cycling results in typical activity decay with dissolution of Ir. • Cysteamine·HCl modified c-NiIrMO performs a highest 2.51 times of Ir mass activity compared to nc-NiIrMO. • Cysteamine·HCl not only plays a role in particle fining but also contributes to the formation of active Ir–OH. • For activation with Ni leaching, surface enlargement plays a key role for c-IrNiMO with Ni content lower than 40%. • Formation of Ir–OH is the dominant factor for the activation of sample with higher Ni content. • A three–step variation process dominated by Ni and Ir dissolution can be observed in the activation-decay process. [ABSTRACT FROM AUTHOR]

The development of alternative (and free-of-antibiotics) antibacterial and antibiofilm agents is an important strategy to circumvent the resistance of bacteria to antibiotics. Herein, we explore the production of mixed oxides by incorporating silver nanoparticles in titanium dioxide as a silver concentration-dependent antibacterial agent that is further incorporated in Tilapia fish skin (a promising prototype of xenograft), integrating the antibacterial activity of mixed oxide into the intrinsic properties of Tilapia skin. The antibiofilm activity of samples prepared with high concentrations of silver (10 wt% of precursor AgNO3) has been considered a good antibiofilm response. The influence of silver content is also observed with respect to the minimum bactericidal concentration, which is reduced to 3.13 mg/mL with a characteristic kill time in the order of 30 min that is associated with antibiofilm activity in biofilm-forming strains of Staphylococcus aureus. These results indicate that modified Tilapia fish skin acquires antibacterial behavior and can be explored for xenografts with prospective applications in the light-dependent actuation of TiO2-based compounds. [ABSTRACT FROM AUTHOR]

In the CO2 hydrogenation reaction, selective synthesis of CO at low temperature and high pressure is needed to integrate the reverse water gas shift reaction with Fischer‐Tropsch synthesis. Here, we show that a mixed oxide catalyst prepared by doping indium (In) into TiO2 produces CO with the formation rate of 22 μmol g−1 s−1. The CO selectivity was more than 99 % at 350 °C and 3 MPa pressure. Moreover, the catalyst was durable for over 100 h on stream. During reaction the interfacial In3+−O−Ti4+ sites were first reduced in presence of H2 and then oxidized back with CO2 producing CO. Because of the redox mechanism, the formation of methanol and methane was limited. This study shows the development of a promoter‐free oxide catalyst for CO2 hydrogenation and the importance of the redox property at the oxide interface for selective hydrogenation of CO2 to CO under unfavorable conditions. [ABSTRACT FROM AUTHOR]

Pure and mixed oxides were synthesized using three methods, namely, coprecipitation, hydrothermal treatment using CTAB and Pechini treatment using glycerol, and investigated for the transformation of fructose, aiming to determine the influence of textural, structural, and acid-base properties on conversion and selectivity. All systems led to fructose conversion in an aqueous medium, and the factors that influenced the transformation were the textural and structural properties, as well as the number of acid sites present in the catalysts. The best conversions were observed using mixed oxides, highlighting SnNb (CTAB) and SnNb (GLY), showing the importance of the modulation of properties using the synthesis method. All systems were selective mainly for 5-HMF (5-hydroxymethylfurfural) and, to a lesser extent, for the products of the retro-aldolic route, and this selectivity was preserved, regardless of the catalytic system used. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) is the core electrode reaction in energy-related technologies, such as electrolytic water, electrocatalytic carbon dioxide reduction, rechargeable metal-air batteries, and renewable fuel cells. Development of well-stocked, cost-effective, and high-performance OER electrocatalysts is the key to the improvement of energy efficiency and the large-scale commercial implementation of these technologies. Multicomponent transition metal oxides and (oxy)hydroxides are the most promising OER catalysts due to their low cost, adjustable structure, high electrocatalytic activity, and outstanding durability. In this review, a brief overview about the mechanisms of OER is first offered, accompanied with the theory and calculation criteria. Then, the latest advances in the rational design of the related OER electrocatalysts and the modulation of the electronic structure of active sites are comprehensively summarized. Specifically, various strategies (including element doping, defect engineering, and fabrication of binderless catalysts) used to improve the OER performance are detailedly discussed, emphasizing the structure—function relationships. Finally, the challenges and perspectives on this promising field are proposed. [ABSTRACT FROM AUTHOR]

In the current Study, undoped and bismuth doped CuO + ZnO coupled oxide thin films were meticulously deposited on glass substrates utilizing the spray pyrolysis technique. The effect of bismuth doping level in the structural, morphological, optical, electrical and electrochemical properties of these thin films were systematically investigated. X-ray diffraction patterns unequivocally confirmed the polycrystalline nature of the films, showcasing a combination of monoclinic CuO and hexagonal wurtzite ZnO phases. Furthermore, at a doping level of 8 %, the presence of the bismuth phase was observed, indicating its incorporation into the CuO–ZnO matrix. As the bismuth doping level increased, we observed a noticeable improvement in crystallinity and grain size. The distinctive characteristics of the developed thin films underscored a discernible enhancement in physical and electrochemical properties with the increase of bismuth doping level. Subsequently, The 8 % bismuth-doped CuO–ZnO thin films exhibit remarkable efficiency in degrading pharmaceutical compounds. Specifically, within a mere 2-h timeframe, these films demonstrate an exceptional degradation efficiency of 99 % towards Rifampicin, a widely used antibiotic. Moreover, their efficacy extends to other pharmaceutical pollutants, showcasing a significant degradation of 77 % for Ampicillin, an antibiotic commonly used to treat bacterial infections, and an even more substantial degradation of 90 % for Rhodamine B, a prominent dye compound. This underscores the promising potential of 8 % bismuth-doped CuO–ZnO thin films in addressing environmental and health-related challenges associated with pharmaceutical contaminants. • Undoped and bismuth doped CuO + ZnO coupled oxide thin films were meticulously deposited on glass substrates utilizing the spray pyrolysis technique et different doping levels. • Bismuth doped CuO + ZnO exerts a significant influence on both the physical and electrochemical properties of CuO–ZnO thin films. • The 8 % bismuth-doped CuO–ZnO thin films exhibit exceptional degradation efficiency of 99 % towards Rifampicin, a widely used antibiotic. • Their efficacy extends to other pharmaceutical pollutants, showcasing a significant degradation of 77 % for Ampicillin, and 90 % for Rhodamine B,. • The mechanisms of undoped and Bi doped CuO–ZnO coupled oxide thin films for the degradation of Rifampicin, ampicillin and green malachite dye was discussed. [ABSTRACT FROM AUTHOR]

The present work highlights the versatility of a TiO2-Al2O3 mixed oxide bearing highly dispersed gold nanoparticles that was applied in the CO oxidation reaction at room temperature. The TiO2, Al2O3, and TiO2-Al2O3 supports were synthesized by the sol–gel method, while gold nanoparticles were added by the deposition–precipitation with urea method using a theoretical Au loading of 2 wt.%. A promotional effect of the TiO2-Al2O3 support on the activity of gold catalysts with respect to TiO2 and Al2O3 was observed; Au/TiO2-Al2O3 showed outstanding CO oxidation, being active from 0 °C and stable throughout a 24-h test. As for the alumina content (5, 10, and 15 wt.%) in TiO2, it improved the textural properties by retarding the crystal growth and anatase–rutile phase transformation of TiO2, suppressing the deposition of carbon on the catalyst surface and stabilizing the Au nanoparticles even at high temperatures. Gold was highly dispersed with nanoparticle sizes ranging from 1 to 2 nm when H2 was used to treat thermally the Au/TiO2-Al2O3, Au/TiO2, and Au/Al2O3 materials. In addition, the XPS technique helped elicit that Au0 and Au1+ boosted their interaction with the TiO2, Al2O3, and TiO2-Al2O3 supports by means of charge transfer, which resulted in outstanding CO oxidation activity from 0 °C. Likewise, the key factors that control the peculiar catalytic performance in the CO oxidation reaction are discussed, which represents a step forward in the versatility behavior of gold catalysts supported on mixed oxide catalysts. [ABSTRACT FROM AUTHOR]

A ternary oxide of silver, copper, and manganese (Ag2CuMnO4) is prepared by hydrothermal synthesis in an alkaline medium in the presence of sodium peroxodisulfate. The obtained product with the delafossite structure has no admixtures of other crystallized phases and is tested as an ethylene oxidation catalyst. The catalytic properties of the ternary oxide are modified by pretreatments in inert (He, T = 400-600 °C) and reducing (1% CO/He, T = 200 °C) media resulting in partial or complete destruction of the pristine structure. It is established that pre-treatment of the ternary oxide diminishes its catalytic activity in the ethylene oxidation reaction. The main reaction products are ethylene oxide, acetaldehyde, carbon dioxide, and water; their yields depend on the pretreatment type and the changes during the heating–cooling cycle. [ABSTRACT FROM AUTHOR]

The study aimed to develop an electrochemical sensor based on glassy carbon, mixed oxide (SiO2/TiO2/Sb2O5), and carbon black. The material was synthesized, characterized, and used to determine thiamethoxam in raw honey and water. The morphologic structure and electrochemical performance of the sensor was characterized by scanning electron microscopy and cyclic voltammetry. Differential pulse voltammetry with a concentration of 0.1 mol L−1 of Britton-Robinson buffer at pH 7.0 allowed the generation of a method to determine thiamethoxam in a linear range of 0.25 to 100.5 μmol L−1 and with a limit of detection of 0.012 μmol L−1. The system efficiently quantified traces of thiamethoxam in raw honey and tap water samples. The modified sensor did not present interferences of K+, Na+, Ca2+, Mg2+, glyphosate, imidacloprid, and carbendazim. In addition, the device showed good recovery values for thiamethoxam when applied directly to honey and water samples without any treatment, presenting an electrochemical sensor to monitor real-time hazardous substances in environmental and food matrices. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of a novel titania/silica hybrid xerogel subsequently modified with 4-methylpyridine (4-Pic), named TiSi4Pic+Cl− is reported. The physicochemical, structural and thermal properties of TiSi4Pic+Cl− were characterized using several techniques. Anchoring cobalt(II) phthalocyanine (CoTsPc) in TiSi4Pic+Cl− showed greater electroanalytical sensitivity over other sensors built with these materials. A novel electroanalytical method was developed to quantify the noxious biocide pentachlorophenol (PCP) for environmental monitoring. The peak current intensity increased linearly with the analyte concentration in the range between 0.99 and 4.21 μmol L−1, based on the oxidation process (at + 0.81 V, vs. Ag/AgCl) of differential pulse voltammetry (DPV). The estimated limit of detection (LOD) was 29 nmol L˗1. Recovery tests in environmental samples showed a PCP concentration of 2.05 ± 0.03 μmol L−1 (n = 3). The method was statistically validated by comparing the PCP concentrations with those obtained by molecular absorption spectrometry and high-performance liquid chromatography-diode array detection (HPLC–DAD). At a 95% confidence level, no difference between the results was found, therefore confirming the excellent accuracy of the proposed method. [ABSTRACT FROM AUTHOR]

In this study, the traditional mixed oxide process was used to create ZnNb2O6-chopped strands composites. The single phase compound with the chemical formula ZnNb2O6 was generated after sintering at 1100°C for 4 h. For the structural investigation, various quantities of ZnNb2O6-chopped strands were generated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were carried out for the structural analysis, which indicated that the second phase did not form in ZnNb2O6. Additionally, the ZnNb2O6-strands composites were manufactured by hot pressing using the compositions of ZnNb2O6-chopped strands in various proportions and epoxy. The ZnNb2O6-chopped strands compound formed in various weights, and epoxy resin were used to fabricate microwave shielding effectiveness composites. Utilizing a network analyzer, the microwave shielding effect of ZnNb2O6-chopped strands composites was investigated in a range of 6.5-18 GHz. At a thickness of 1.5 mm, a minimum of -51.32 dB shielding effectiveness value was achieved at 6.75 GHz. The ZnNb2O6-chopped strands compounds were produced as composite and their features were characterized for shielding effectivacy. The content of components in the samples may be managed for the larger and needed frequency bands to change the microwave shielding performance. [ABSTRACT FROM AUTHOR]

In this study, titania–silica oxides (TixSiy oxides) were successfully prepared via the sol–gel technique. The Ti and Si precursors were titanium (IV), isopropoxide (TTIP), and tetraethylorthosilicate (TEOS), respectively. In this work, the effects of pH and the Ti/Si atomic ratio of titanium–silicon binary oxide (TixSiy) on the structural characteristics of TixSiy oxide are reported. 29Si solid-state NMR and FTIR were used to validate the chemical structure of TixSiy oxide. The structural characteristics of TixSiy oxide were investigated using X-ray diffraction, XRF, Fe-SEM, diffraction particle size analysis, and nitrogen adsorption measurements. By applying X-ray absorption spectroscopy (XAS) obtained from synchrotron light sources, the qualitative characterization of the Ti–O–Si and Ti–O–Ti bonds in Ti–Si oxides was proposed. Some Si atoms in the SiO2 network were replaced by Ti atoms, suggesting that Si–O–Ti bonds were formed as a result of the synthesis accomplished using the sol–gel technique described in this article. Upon increasing the pH to alkaline conditions (pH 9.0 and 10.0), the nanoparticles acquired a more spherical shape, and their size distribution became more uniform, resulting in an acceptable nanostructure. TixSiy oxide nanoparticles were largely spherical in shape, and agglomeration was minimized. However, the Ti50Si50 oxide particles at pH 10.0 become nano-sized and agglomerated. The presence of a significant pre-edge feature in the spectra of Ti50Si50 oxide samples implied that a higher fraction of Ti atoms occupied tetrahedral symmetry locations, as predicted in samples where Ti directly substituted Si. The proportion of Ti atoms in a tetrahedral environment agreed with the value of 1.83 given for the Ti–O bond distance in TixSiy oxides produced at pH 9.0 using extended X-ray absorption fine structure (EXAFS) analysis. Photocatalysis was improved by adding 3% wt TiO2, SiO2, and TixSiy oxide to the PLA film matrix. TiO2 was more effective than Ti50Si50 pH 9.0, Ti50Si50 pH 10.0, Ti50Si50 pH 8.0, and SiO2 in degrading methylene blue (MB). The most effective method to degrade MB was TiO2 > Ti70Si30 > Ti50Si50 > Ti40Si60 > SiO2. Under these conditions, PLA/Ti70Si30 improved the effectiveness of the photocatalytic activity of PLA. [ABSTRACT FROM AUTHOR]

In this study, tin oxide (SnO 2), molybdenum oxide (MoO 3) and a mixed oxide based on tin and molybdenum (respectively, Sn100, Mo100 and SnMo25, synthesized by the impregnation method) were applied in xylose conversion. The best results were obtained employing Mo100 and SnMo25. In the presence of SnMo25, after 0.5 h, xylose conversions of 39.5%, 34.1% and 63.4% were obtained, respectively, at 110, 130 and 150 °C. For Mo100, conversions of 49.6%, 71.8% and 85.3% were attained under the same reaction conditions, showing that Mo100 provided the best conversion results. However, with the use of this catalyst there was an increase in the amount of soluble and insoluble polymeric material. In terms of the soluble products formed from xylose, depending on the reaction condition were detected xylulose (X), lyxose (L) and furfural (FUR), glyceraldehyde (GL), pyruvaldehyde (PYR), glycoaldehyde (GLYC), dihydroxyacetone (DHA), lactic acid (AL), levulinic acid (LA) and acetic acid (AA). However, with the use of Sn100 or without a catalyst (systems with low conversions) there was mainly the formation of lyxose. The use of Mo100 and SnMo25 (systems which exhibit high acidity) leads mainly to isomerization, epimerization and dehydration reactions, as in the case of the retro-aldol pathway and furfural conversion, highlighting the importance of Lewis and Bronsted acid sites in relation to modulating the selectivity of the systems. [Display omitted] • Individual and mixed metal oxide of tin and molybdenum were synthesized. • Catalysts were applied in xylose conversion. • Mo100 and SnMo25 lead to best xylose conversion. • Lewis and Bronsted acid sites can modulate the selectivity. [ABSTRACT FROM AUTHOR]

Mixed oxide titanium dioxide (TiO 2) and fluorine doped tin oxide (SnO 2 :F) thin films have been grown, using spray pyrolysis technique, at various substrate temperatures (Ts) ranging from 250 to 400 °C with a step of 50 °C. Samples were examined using X-ray diffraction (XRD), optical microscopy, spectrophotometry and spectrofluorimetry, with special emphasis on the evolution of their physico-chemical properties versus substrate temperature. In fact, X-ray diffraction analysis showed that a substrate temperature of about 350 °C exhibits the presence of both anatase phase of TiO 2 and tetragonal structure of SnO 2 :F compounds. A direct band gap of about 3.91 eV was obtained. Envelope method, based on transmission spectrum, was investigated in order to estimate the film thickness and some optical parameters such as real and imaginary parts of dielectric constant. Wemple Di-Dominico and Spizer Fan models were applied in order to determine the effect of substrate temperature on some dispersion parameters. Photoluminescence spectra showed different emissions in the visible region. The photodegradation mechanism of both Rhodamine B (RhB) and Malachite Green (MG) pollutants using TiO 2 –SnO 2 :F coupled oxide layer, grown at 350 °C, was discussed and an efficiency of about 90 %, after 3 h of sun irradiation, was achieved. Additionally, the layer exhibits good stability, recoverability and reusability after a cyclic test of 9 h, making it suitable for industrial applications. As a secondary application, a numerical simulation of TiO 2 –SnO 2 :F/CdS/CIGS solar cell, using SCAPS-1D software, was investigated for the first time. An open circuit voltage of about 613 mV was obtained, the current density Jsc was in the order of 33.49 mA/cm2, the Fill Factor FF and the efficiency were in the order of 79.13, 16.23 %, respectively. • TiO 2 –SnO 2 :F thin films have been, successfully, deposited on glass substrates using spray pyrolysis technique. • The growth of mixed oxide thin films at a substrate temperature of about 350 °C ensures the presence of both anatase TiO 2 compound as well as tetragonal structure of SnO 2 compound. • Both Wemple–Di Domenico and Spitzer–Fan models have been used in order to determine some optical constants. • The photocatalytic activity of TiO 2 –SnO 2 :F compound as catalysis for both malachite green (MG) and Rhodamine B (RhB) pollutants has been evaluated and an efficiency of about 90 % is obtained. • TiO 2 –SnO 2 :F mixed oxide thin layers has been used as an optical window in TiO2–SnO2:F/CdS/CIGS solar cell and SCAPS-1D package was used in order to simulate its performance. The obtained results show a promising efficiency of about 16.23 % [ABSTRACT FROM AUTHOR]

TiO2, ZnO, and their combination (TiO2–ZnO) at different molar ratios and pH values (Ti–Zn A and B 3:1, 1:1, and 1:3) via the sol–gel method were characterized by SEM, XRD, UV-Vis, and FT-IR. Moreover, antibacterial tests of the nanoparticles were conducted against Escherichia coli (E. coli), Salmonella paratyphi (S. paratyphi), Staphylococcus aureus (S. aureus), and Listeria monocytogenes (L. monocytogenes). The indirect bandgap of the Ti–Zn binary oxide synthesized in the basic process at molar ratios of 3:1, 1:1, and 1:3 exhibited a higher eV (3.31, 3.30, and 3.19 eV, respectively) compared to pure TiO2 (3.2 eV) and synthesized in the acid process (3.22, 3.29, and 3.19 eV at same molar ratio, respectively); in addition, the results of the indirect bandgap were interesting due to a difference found by other authors. Moreover, the sol–gel method promoted the formation of a spherical, semi-sphere, and semi-hexagonal shape (TiO2, Ti–Zn 1:1, and Ti–Zn 1:3) with a size ≤ 150 nm synthesized during the acid process, with a crystallite size of ~71, ~12, ~34, and ~21 nm, respectively, while ZnO NPs developed a hexagonal and large size (200–800 nm) under the same synthesis process (acid). Samples were classified as TiO2 anatase phase (basic synthesis); however, the presented changes developed in the rutile phase (24% rutile phase) at an acid pH during the synthesis process. Moreover, Ti–Zn maintained the anatase phase even with a molar ratio of 1:3. The most interesting assessment was the antibacterial test; the Ti–Zn A (1:3) demonstrated a bacteriostatic effect compared with all treatments except ZnO, which showed a similar effect in dark conditions, and only Gram-positive bacteria were susceptible (Listeria monocytogenes > Staphylococcus aureus). Therefore, the Ti–Zn characteristic suggests that the results have potential in treating wastewater as well as in pharmaceutical (as drug carriers) and medical applications. [ABSTRACT FROM AUTHOR]

The Pb(Mg1/3Nb2/3)O3-based ceramic system was obtained by using a modified variant of the conventional ceramic method in order to get pyrochlore-free compositions. Solid solutions obtained from Pb(Mg1/3Nb2/3)O3 and Ln(Mg1/2Ti1/2)O3 with Ln = Y3+, La3+, Pr3+, Nd3+ and Sm3+, were synthesized using a 3-step columbite precursor method and appropriate milling and sintering conditions. The structural phases of all sintered compositions were investigated in detail. The X-ray diffraction results demonstrate that all the samples possess a perovskite structure. The influence of dopant on the incorporation degree in the solid solutions was studied. The dielectric constants at three frequencies were measured and the influence of the dopant on these values was discussed. [ABSTRACT FROM AUTHOR]

Zinc-aluminum based layered double hydroxide (ZnAl-LDH), -oxide (ZnO), -mixed oxide (Zn6Al2O9), and zinc-aluminum mixed oxide/polyvinyl alcohol (ZnAl-mixed oxide/PVA) nanocomposite have been synthesized. The samples were characterized using some analytical methods: Ultraviolet-visible spectroscopy, Fourier transforms infrared (FTIR) spectroscopy, x-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive x-ray spectroscopy. The XRD patterns of ZnAl-LDH5M and ZnAl-LDH2M show the characteristic reflections of ZnO phase beside the hydrotalcite-like structure. Using NaHCO3 in the experiment, the precipitation speed of the sample was high and in this regard, the particle size of ZnAl-LDHurea(1) was 22.37 nm. ZnAl-LDH2M and ZnAl-LDH5M describe three optical band gaps with three different energies. For ZnAl-mixed oxide/PVA, there are two types of electronic transitions could exist at ZnO which attributed to the filled O2p orbital and that associated to the empty Zn 4s orbital, with the possibility of some Zn 4p orbital. Another electronic transition could exist for Zn6Al2O9 between the filled O 2p orbital and the empty Al 3s orbitals, with the additional possibility of some Al 3p orbital. The intense FTIR band at very low wavenumber is observed for only ZnAl-LDHurea(2) which attributed to the Zn-O-bound for brucite-like LDH structures. [ABSTRACT FROM AUTHOR]

Mixed oxides of Ni0.65Zn0.35Fe2O4 stoichiometry (Ni + Zn/Fe = 1:2) were prepared by citrate and coprecipitation methods, characterized by TGA-TD, XRD, FTIR and SEM, and its catalytic properties were investigated in hydrogenation of 2-nitrophenol (2-NP) to 2-aminophenol (2-AP) counterparts under ambient conditions. The methods of preparation influenced the textural, the structural and the reactivity properties. All the preparations show the presence of mixed phases containing spinel structure and γ-Fe2O3 oxide. The crystallite sizes increase with increasing calcination temperatures due to the coalescence of nanoparticles by solid-state diffusion. All samples exhibited high catalytic activity with first-order kinetic; the sample issued from citrate method and annealed at 800 °C (Ea ~ 31.6 kJ/mol) is the most active system with a high X-ray density and a low force constant at tetrahedral sites. For this catalyst, 99.7% of 2-NP was reduced to 2-AP within 6.5 min and the recycled catalyst shows a very good activity for five catalytic runs. It could remain more than 88% activity after it was used five times. [ABSTRACT FROM AUTHOR]

Calculated critical and subcritical data for systems of mixed oxides of plutonium and uranium are presented for review and subsequent incorporation into a revision of ANSI/ANS 8.12. The system specifications were prepared in parallel with the ISO standard ISO 11311:2011, involving experience from international mixed oxide fuel fabrication facilities. Data are presented for two mass fractions of plutonium to uranium plus plutonium (at 12.5% and 35%), damp mixed oxide density up to a theoretical density of 11.03 g/cm3 (for the 12.5% mass fraction, ignoring the variation due to plutonium isotopic content) and up to a density of 3.5 g/cm3 (for the 35% mass fraction), three plutonium isotopic mass fractions (100% 239Pu, 95% 239Pu with 5% 240Pu, and a reactor grade composition with 20% 240Pu and the balance 239Pu, 241Pu, and 242Pu), systems at two moderation conditions (water mass fractions at 3% and at optimal conditions) and systems at two water reflector conditions (nominal 2.5 cm and full 30.0 cm). Parameters of interest presented are values of volume (L), infinite cylinder diameter (cm), infinite slab thickness (cm), mass (kg), cylinder linear density (g/cm), and slab areal density (g/cm2). Values are presented at calculated multiplication factors of 1.000, 0.980 and 0.950. Calculations were made by various subject matter experts with various computational programs and cross section libraries. Validation methods were reviewed and discussed herein though data propagated to revision of ANSI/ANS 8.12 will reflect a conservative subcritical margin selected based on expert judgment. [ABSTRACT FROM AUTHOR]

This study investigates the use of CaO–TiO2 mixed oxides as solid base catalysts to produce biodiesel from cotton oil (Gossypium hirsutism). These CaO–TiO2 mixed-oxide catalysts were prepared in different molar proportions of Ca:Ti (0.75Ca:0.25Ti, 1Ca:1Ti e 0.25Ca:0.75Ti) and characterized by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TGA), Raman spectroscopy, scanning electron microscopy (SEM) coupled with energy-dispersive X-ray analysis, and Brunauer–Emmett–Teller surface area analysis. The effects of reaction parameters such as the methanol/oil molar ratio, the amount of catalyst amount, and the reaction temperature were also investigated. The process was evaluated by TGA and confirmed by FTIR and GC/MS. The catalysts obtained were tested in the following reaction parameters: 20:1 methanol:oil molar ratio; 10% of catalyst amount; and 60 °C temperature for 5 h. The best catalyst was determined to be 0.25Ca–0.75Ti (calcined at 800 °C), considering its catalytic and anti-leeching abilities, because it obtained the highest yield (92.2%) without leaching calcium. Therefore, CaO–TiO2 catalysts have the potential to be used in biodiesel products. [ABSTRACT FROM AUTHOR]

In this work, we designed a polycrystalline Cu‐CeO2 catalyst with defect sites, and it has superior CO oxidation activity in presence of excess H2. The oxygen defects of Cu‐CeO2 influence the adsorption of unalike surface di‐oxygen types, and the catalyst was characterized through XRD (X‐Ray Diffraction) analysis, TEM (Transmission electron microscopy), in‐situ Raman spectroscopy, in‐situ DRIFT (Diffuse reflectance infrared fourier transform) spectroscopy. TEM showed that CeO2(111) plane are the exposed plane for this reaction. Raman spectroscopy showed nature of the defects of the prepared catalyst and how it works in the reaction environment. In‐situ DRIFT spectroscopy showed that the Cu+↔Cu2+ system is working in this reaction environment. Role of interfacial Cu ions was confirmed by in‐situ DRIFT spectroscopy and DFT (Density functional theory) study. [ABSTRACT FROM AUTHOR]

In this work, we designed a polycrystalline Cu‐CeO2 catalyst with defect sites, and it has superior CO oxidation activity in presence of excess H2. The oxygen defects of Cu‐CeO2 influence the adsorption of unalike surface di‐oxygen types, and the catalyst was characterized through XRD (X‐Ray Diffraction) analysis, TEM (Transmission electron microscopy), in‐situ Raman spectroscopy, in‐situ DRIFT (Diffuse reflectance infrared fourier transform) spectroscopy. TEM showed that CeO2(111) plane are the exposed plane for this reaction. Raman spectroscopy showed nature of the defects of the prepared catalyst and how it works in the reaction environment. In‐situ DRIFT spectroscopy showed that the Cu+↔Cu2+ system is working in this reaction environment. Role of interfacial Cu ions was confirmed by in‐situ DRIFT spectroscopy and DFT (Density functional theory) study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mixed metal oxides based on tin and niobium were synthesized. • Pechini method replacing ethylene glycol with glycerol was used. • Mixed oxides lead to best fructose conversion. • High selectivity to 5-HMF. • Reuse without structural change in the catalysts. The selective and efficient conversion of fructose into chemicals has been extensively explored, especially from the perspective of a more sustainable industry based on renewable inputs together with a more environmentally friendly process. In this study, mixed metal oxides based on tin and niobium were synthesized by the Pechini method, replacing ethylene glycol with glycerol, a renewable chemical. This replacement allows the use of pure or mixed oxides exhibiting high specific surface areas but did not lead to significant differences in the amount and nature of the acid sites present in each case. Furthermore, the mixed oxides had increased numbers of Lewis acid sites, while the number of Bronsted acid sites decreased. Catalytic tests performed at 150 °C demonstrated that the use of these materials leads to conversion results higher than those observed for pure oxides (SnO 2 (EG) = 48.3 %, Nb 2 O 5 (EG) = 51.6 % and SnO 2 (G) = 56.8 %, Nb 2 O 5 (G) = 59.6 %) because 78.5 and 75.7 % consumption of fructose for SnNb (EG) and SnNb (G) was attained at 2 h, respectively. In addition, the catalysts show promising 5-hydroxymethylfurfural (5-HMF) selectivity, and the presence of lactic acid was also detected. In addition, recycling experiments were performed, and stability was observed for 4 cycles without structural change in the catalysts. [ABSTRACT FROM AUTHOR]

Various loadings of copper supported on MoO3/SiO2 (CMS) were prepared by sol-gel method and used for the synthesis of substituted benzimidazole. Further it was characterized by using X‐ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), and acidity measurement by potentiometric method. XRD results indicated that Cu is present on the support primarily as CuO. The SEM and TEM results showed dispersion of cubic CuO nanoparticles on the surface. These mixed oxides were studied for the acylation of o-phenylene diamine with acetic acid in liquid phase. 10 wt. % CMS gave best results at 110 ºC with 94.81 % conversion of o-phenylene diamine and 100 % selectivity of substituted benzimidazole. Different parameters were studied for optimization of acylation, such as: temperature, acylating agents, solvents, amount of catalyst, and different catalysts. The CMS catalyst could also be recovered and reused at three times without any discernible decrease in its catalytic activity.