Effect of oxygen vacancy influenced by CeO2 morphology on the methanol catalytic reforming for hydrogen production

Abstract

Methanol reforming has been a popular pathway to produce hydrogen due to the high hydrogen storage density of methanol. CeO2 as the support is widely used for catalytic methanol reforming, but the effect of CeO2 morphology on the reaction mechanism has not been revealed out. In this study, the catalytic performances of Ru/CeO2 with different CeO2 morphology, including rod, cubic and their mixed, were investigated in methanol reforming for the production of hydrogen. By regulating the temperature during hydrothermal preparation, different CeO2 supports can be achieved. Results showed that Ru/CeO2 catalyst with rod CeO2 (Ru/r-CeO2) exhibited a much better catalytic performance than the cubic catalyst (Ru/c-CeO2) and the mixed catalyst (Ru/m-CeO2), with a higher yield of hydrogen and a lower selectivity of CO product. This was mainly due to the large surface area that favored the dispersion of Ru metal site and the interaction between Ru and CeO2 support that improved the electron transfer to benefit the formation of oxygen vacancy. Therefore, the Ru/r-CeO2 catalyst possessed abundant oxygen vacancy, which enabled to adsorb the methanol efficiently and trigger the methanol reforming reaction. It also can enhance the adsorption of CO and water and promote the water-gas-shift reaction to increase the yield of hydrogen production.