Plasma-enhanced dispersion of Cr2O3 over ceria-doped MCM-41 nanostructured catalyst used in CO2 oxidative dehydrogenation of ethane to ethylene

Abstract

Abstract A series of chromium oxide catalysts supported on the mesoporous Ce-MCM-41 molecular sieves with different (Si/Ce) molar ratios have been synthesized by hydrothermal/impregnation method and compared with the catalysts treated by plasma energy. The effect of Si/Ce molar ratio on the catalytic activity of Cr/MCM-41 nanocatalysts in dehydrogenation of ethane with CO2 was examined. The nanocatalysts were characterized by XRD, FESEM, EDX, TEM, BET and FTIR analysis. According to the results obtained by XRD analysis, by increasing the amounts of ceria in the support the content of α-Cr2O3 phase decreased. Also, the results of FESEM analysis indicates that particle size decreased by increasing ceria content and more uniform morphology achieved. Actually, the better characteristic properties and catalytic activity obtained when the molar ratio of Si/Ce was considered 25. On the other hand utilization of plasma energy in catalyst treatment developed a catalyst with better dispersion of chromium oxide and more uniform morphology and smaller particle size compared to the untreated catalyst. This nanocatalyst remains stable after 300 min time on stream reaction and 62.3% of ethylene yield achieved on it at 700 °C.