RESUMEN
Methanol, produced through the hydrogenation of carbon dioxide, is an essential intermediate compound that plays a crucial function in the production of various organic chemicals. Enhancing the design of copper-containing catalysts for the transformation of CO2 to methanol is a popular strategy in scientific literature, although challenges persist in advancing the efficiency of carbon dioxide transformation and the selectivity of methanol production. This research aims at creating CuZnO-M/rGO (M = Mg, Mn, and Cr) catalysts using an efficient method for selectively converting CO2 to methanol. By optimizing the operational parameters of this system, methanol productivity and CO2 conversion efficiency are enhanced. Under optimal conditions, a CO2 conversion rate of 23.5%, methanol selectivity of 90%, and a space-time yield of 0.47 gMeOH.gcat-1.h-1 were achieved with the CuZnO-MgO (5)/rGO catalyst. These levels were maintained over a 100-h period, demonstrating the stability of the catalyst system. These findings are highly consistent with the density functional theory (DFT) calculations, revealing that the CuZnO-MgO (5)/rGO catalyst possesses a -0.35 eV adsorption energy for CO2 and a favorable reaction pathway with the overpotential of 1.16 V towards methanol production emphasizing the high conversion and selectivity obtained.
Asunto(s)
Dióxido de Carbono , Cobre , Metanol , Metanol/química , Catálisis , Dióxido de Carbono/química , Cobre/química , Óxido de Zinc/química , Carbono/química , AdsorciónRESUMEN
In this contribution, CoW/X materials (X = CNT or CNF) were utilized as oxidative desulfurization (ODS) catalysts for the removal of dibenzothiophene (DBT) from a model fuel (n-decane), incorporating the H2O2 as an efficient oxidant. Different operating conditions were investigated. Both compounds revealed high desulfurization efficiency using milder operating conditions leading to low levels of the DBT compound since only 1 h while using a low ratio of H2O2/S = 6. Among synthesized compounds, the CoW (15)/CNT showed superior DBT conversion through the ODS process. In other words, the highest sulfur removal efficiency of 100% for a feed sulfur content of 500 ppm was determined in a 40-min duration under optimum conditions. This was satisfyingly more effective than a recently reported CoW (20)/rGO catalyst. The characterization of synthesized catalysts was performed in order to evaluate their physicochemical properties. Moreover, product identification of the oxidation desulfurization process was performed using the GC-Mass, FTIR, and NMR techniques where it was found that this process was that of a single product. These experimental studies were complemented with density functional theory (DFT) investigations, which indeed shed important light on understanding the adsorption mechanisms as well as electronic properties of the system undertaken.