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The synergy between catalysis and plasma chemistry often enhances the yield of chemical reactions in plasma-driven reactors. In the case of CO2 splitting into CO and O2, no positive synergistic effect was observed in earlier studies with plasma reactors, except for dielectric barrier discharges, that do not have a high yield and a high efficiency. Here, we demonstrate that introducing metal meshes into radio frequency-driven plasma reactors increases the relative reaction yield by 20%–50%, while supported metal oxide catalysts in the same setups have no effect. We attribute this to the double role of the metal mesh, which acts both as a catalyst for direct CO2 dissociation as well as for oxygen recombination. [ABSTRACT FROM AUTHOR]

MXenes are a new family of 2D carbides or nitrides that have attracted attention due to their layered structure, tunable surface groups and high electrical conductivity. Here, we report for the first time that the Ti2CTx MXene catalyses the selective oxidative dehydrogenation of n‐butane to butenes and 1,3‐butadiene. This catalyst showed higher intrinsic activity compared to a commercial TiC and TiO2 samples in terms of C4 olefin formation rate. We propose that the stabilisation of structural vacancies and the change in composition (from a carbide to a mixed phase oxide) in the MXene causes its higher catalytic activity. These vacancies can lead to a higher concentration of unpaired electrons in the MXene‐derived material, enhancing its nucleophilic properties and favouring the production of olefins. [ABSTRACT FROM AUTHOR]

We study the catalytic condensation of furfuryl alcohol with 1-butanol to butyl levulinate. A screening of several commercial and as-synthesized solid acid catalysts shows that propylsulfonic acid-functionalized mesoporous silica outperforms the state-of-the-art phosphotungstate acid catalysts. The catalyst is prepared via template-assisted sol-gel polycondensation of TEOS and MPTMS. It gives 96 % yield (and 100 % selectivity) of butyl levulinate in 4 h at 110 °C. Reaction profiles before and after a hot filtration test confirm that the active catalytic species do not leach into the solution. The catalyst synthesis, characterization, and mode of operation are presented and discussed. [ABSTRACT FROM AUTHOR]

A systematic study of catalytic ethylation of phenol is carried out with ethanol as a function of feed composition, time on stream (TOS), temperature, and catalyst composition over Cu1-xCoxFe2O4 (x=0.0–1.0) ferrospinel system. Phenol ethylation gives 2-ethyl phenol as a major product under the reaction conditions employed, while its selectivity decreases as temperature and Co-content increases. Compositions containing both Cu and Co (0

A systematic study on catalytic methylation of phenol is carried out with methanol as a function of reaction temperature and catalyst composition on a Cu1−xCoxFe2O4 (x=0.0 to 1.0) ferrospinel system. Phenol methylation gives two major products, namely o-cresol and 2,6-xylenol. Large phenol conversion and 2,6-xylenol production are observed at 350°C and x=0.5 shows good catalytic performance. Increase in selectivity of 2,6-xylenol at the expense of o-cresol demonstrates that the phenol methylation is sequential. X-ray diffraction of fresh catalysts reveals the formation of the spinel phase along with a mixture of CuO and α-Fe2O3 phases at x=0.0, while trace amounts of α-Fe2O3 are found for x≥0.25. Spent catalysts display better crystallinity, hinting at the integrity of the structure. X-ray photoelectron spectroscopy and X-ray-induced Auger electron spectroscopy reveal the presence of Cu2+, Fe3+, Co2+, and Co3+ species on fresh catalysts. Metal ions reduce partially to lower oxidation states on spent catalysts. Reducibility of Cu2+ species decreases with increasing x. Valence band photoemission studies demonstrate a clear change in the overlap between 3d bands of Cu, Co, and Fe from fresh to spent catalysts. The better catalytic results observed with x=0.5 are attributed to an optimum distribution of Cu species with heteroatom neighbors on the surface, and the maximum overlap between the Cu and Co 3d bands makes the ferrospinel integrate chemically and electronically. [Copyright &y& Elsevier]