Low-Temperature Catalytic CO2 Dry Reforming of Methane on Ni-Si/ZrO2 Catalyst

The activity of a ZrO2-supported nickel catalyst promoted by silica (Ni-Si/ZrO2) in CO2 dry reforming of methane was carried out at 400 and 450 °C. The catalysts were prepared by an impregnation method and characterized by H2-TPR, XRD, TEM, TG-MS, Raman, XPS, and in situ XPS and DRIFTS. It was discovered that Ni-Si/ZrO2 showed higher initial conversion of CH4 (0.50 s–1) and CO2 (0.44 s–1), and stability for low temperature (400 °C) DRM reaction in comparison to an SiO2-supported nickel catalyst promoted by zirconia (Ni-Zr/SiO2) (0.32 s–1 for both CO2 and CH4). The Ni-Si/ZrO2 catalyst featured the formation of active nickel particles with a small size of 6–9 nm and with slightly strong electronic donor ability, stabilization of the initial metal nickel state under the reaction conditions, and the formation of easily removed C1 coke. However, for the 450 °C DRM reaction, the coke that formed on the Ni-Si/ZrO2 catalyst was mainly C2 coke that was difficult to remove, because the CO2 preferred to combine with H species rather than react with the coke. For the Ni-Zr/SiO2 catalyst, the Ni0 species was oxidized to a NiO species under the reaction conditions at 400 °C and could not be restored, leading to its deactivation.