Optimized Ni-based catalysts for methane reforming with O2-containing CO2

Abstract

Reduction of CO2 in presence of oxidative impurity (e.g., O2) is more promising than utilization of pure CO2 due to skyrocketing cost for purification of captured CO2 from air or industrial exhaust gas. In this work, Ni-based catalysts are modified by CeO2 and ZrO2 to suppress negative effect of O2 on reforming of CO2 with methane, which show high CH4 conversion (97 %) and CO2 conversion (95 %) at 750 °C and can maintain high CO2 conversion even with high O2 content. The physicochemical characterizations on fresh and spent catalysts show that the interaction among Ni, CeO2 and ZrO2 results in well dispersion of smaller Ni particles, even after long-term testing. In situ DRIFTS results show that Ni/CeO2-ZrO2-SiO2 catalyst shows advantage to activate CH4 to generate active CH3*, promoting the formation of CO, and the CeO2-ZrO2 solid solution improves the CO2 adsorption, thereby reducing the competitive effect of CO2 and O2.