Suppressing Metal-Support Interaction Enhances Photothermal CO<sub>2</sub> Methanation on the Ru/CeO<sub>2</sub> Catalysts
Yun Zhou, Peng Zheng, Jiajian Gao, Wenqing Xu, Yang Yang, Lili Zhang, Tingyu Zhu, Guangwen Xu, Ziyi Zhong, Fabing Su
Abstract
Metal-support interactions can significantly affect the catalytic performance of heterogeneous catalysts and have been studied extensively in thermal catalysis and electrocatalysis. However, the role of strong metal-support interactions (SMSIs) in regulating photoinduced electron transfer has been rarely investigated in photocatalysis. In this study, we have prepared two model catalysts using the impregnation method─one with SMSI effect (Ru/CeO 2 ) and the other with suppressed SMSI effect (Ru/CeO 2 –H 2 )─and tested them for photothermal CO 2 methanation. The methane production rate of Ru/CeO 2 –H 2 (275.1 mmol/g Ru /h) was more than twice that of Ru/CeO 2 (111.2 mmol/g Ru /h) at 200 °C under light irradiation. Various characterizations and theoretical calculations suggest that hot electrons, generated by local surface plasma, transferred to the Ru/CeO 2 –H 2 from the dispersed Ru sites, filling the oxygen vacancies in Ru/CeO 2 –H 2, where the adsorption and activation of CO 2 was enhanced under light irradiation. Also, it is evident that the electron-deficient Ru sites speed up the decomposition of H 2 . The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies showed that CO 2 methanation on Ru/CeO 2 –H 2 and Ru/CeO 2 chiefly followed the formate-intermediated pathway, although the CO-intermediated pathway was also present. This study offers a technique to enhance photothermal CO 2 methanation by controlling the interaction between the metal and the support.