MnOx-Promoted, Coking-Resistant Nickel-Based Catalysts for Microwave-Initiated CO2 Utilization

The most important factors in improving the stability of nickel-based catalysts for methane reforming with carbon dioxide (so-called methane dry reforming, MDR) lie both in suppressing carbon formation and in inhibiting metal sintering at the high operating temperatures of this process (typically above 700 degrees C). Many efforts have been made to overcome these challenges, for example, by enhancing metal catalyst-support interactions. In this work, we used microwaves as an energy source to drive the MDR reactions under mild conditions with an overall measured catalyst bed temperature of below 220 degrees C. A high CH4 conversion of ca. 94% and a 97% conversion of CO2 were achieved over manganese-oxide modified ZrO2-supported nickel catalysts, exhibiting excellent anticoking properties. Compared with Ni/ZrO2 and Mn/ZrO2 catalysts, the Ni-Mn bimetal catalytic system stabilizes the catalytic activity of MDR by suppressing carbon deposition with the mixed-valent Mn3+/Mn2+ chemical states enhancing the absorption and conversion of CO2 during the reactions.