Cu/ZnO and Cu/ZnO/ZrO2 catalysts used for methanol steam reforming

Abstract

Cu/ZnO and Cu/ZnO/ZrO2 catalysts were prepared by co-precipitation method and used in methanol steam reforming at 250 °C. The catalysts were characterized by N2 adsorption, X-ray diffraction (XRD), temperature-programmed reduction (TPR), H2 temperature-programmed desorption (H2-TPD), transmission electron microscopy (TEM), X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). ZrO2 affect the textural, structural and morphological properties of the CuO/ZnO catalyst. ZrO2 nanoclusters or amorphous material was found in Zr-based catalyst which role was to prevent the CuO and ZnO crystallite growth causing a microstrain in Cu and Zn oxides lattice. This effect facilitated the formation of exposed CuO species, which were easier to reduce and favored the catalytic performance of Zr-based catalyst. Monoclinic ZrO2 found in Zr-based catalyst decrease the CO formation deeply because of the higher capacity of monoclinical ZrO2 to adsorbed CO. The Cu2O active site found in CuO/ZnO catalyst was not more efficient than active sites in Zr-based catalyst. The results confirmed that the interactions between Cu and ZnO/ZrO2 were different from those between Cu and ZnO.