A Novel Synergetic Effect Between Ru and CeO2 Nanoparticles Leads to Highly Efficient Photothermocatalytic CO2 Reduction by CH4 with Excellent Coking Resistance

Highly efficient photothermocatalytic CO 2 reduction by CH 4 (CRM) on Ru/CeO 2 is realized by merely using focused UV–vis–IR irradiation. It shows very high production rates of H 2 and CO (57.37 and 65.79 mmol min −1 g −1 ), and a large light‐to‐fuel efficiency (30.6%), much higher than those of Ru/Al 2 O 3 . It also shows good catalytic durability and excellent coking resistance with an extremely low coke formation rate ( r C ), 30.6 times lower than that of Ru/Al 2 O 3 . This is attributed to a synergetic effect between Ru and CeO 2 nanoparticles. The formation of a Ru/CeO 2 interface promotes CH 4 dissociation on Ru nanoparticles. The produced carbon species is not only oxidized by the oxygen produced by CO 2 dissociation on Ru nanoparticles like Ru/Al 2 O 3 , but also by the active oxygen of CeO 2 . CO 2 molecules strongly adsorb on the resultant oxygen vacancies of CeO 2 , forming a CO 2 molecule fence around Ru nanoparticles, accelerate the oxidation of carbon species, thus improving catalytic activity and tremendously reducing r C . The photothermocatalytic CRM on Ru/CeO 2 follows a light‐driven thermocatalysis mechanism. A novel photoactivation is found to enhance the catalytic activity due to both CH 4 dissociation and the oxidation of carbon species being promoted upon light irradiation.