Revealing the Promoting Effect of CeO2 on the Cu/ZnO Catalyst for Methanol Steam Reforming

Cu-based catalysts have been extensively used in methanol steam reforming (MSR) reactions because of their low cost and high efficiency. ZnO is often used in commercial Cu-based catalysts as both a structural and an electronic promoter to stabilize metal Cu nanoparticles and modify metal-support interfaces. Still, the further addition of chemical promoters is essential to further enhance the MSR reaction performance of the Cu/ZnO catalyst. In this work, CeO2-doped Cu/ZnO catalysts were prepared using the coprecipitation method, and the effects of CeO2 on Cu-based catalysts were systematically investigated. Doping with appropriate CeO2 amounts could stabilize small Cu nanoparticles through a strong interaction between CeO2 and Cu, leading to the formation of more Cu+-ZnOx interfacial sites. However, higher CeO2 contents resulted in the formation of larger Cu nanoparticles and an excess of Cu+-CeOx interfacial sites. Consequently, the Cu/5CeO(2)/ZnO catalyst with maximal Cu-ZnO interfaces exhibited the highest H-2 production rate of 94.6 mmolH(2)/(g(cat) & sdot; h) , which was 1.5 and 10.2 times higher than those of Cu/ZnO and Cu/CeO2, respectively.