Photo-thermal coupling to enhance CO 2 hydrogenation toward CH 4 over Ru/MnO/Mn 3 O 4 .

Upcycling of CO 2 into fuels by virtually unlimited solar energy provides an ultimate solution for addressing the substantial challenges of energy crisis and climate change. In this work, we report an efficient nanostructured Ru/MnO x catalyst composed of well-defined Ru/MnO/Mn 3 O 4 for photo-thermal catalytic CO 2 hydrogenation to CH 4 , which is the result of a combination of external heating and irradiation. Remarkably, under relatively mild conditions of 200 °C, a considerable CH 4 production rate of 166.7 mmol g -1 h -1 was achieved with a superior selectivity of 99.5% at CO 2 conversion of 66.8%. The correlative spectroscopic and theoretical investigations suggest that the yield of CH 4 is enhanced by coordinating photon energy with thermal energy to reduce the activation energy of reaction and promote formation of key intermediate COOH* species over the catalyst. This work opens up a new strategy for CO 2 hydrogenation toward CH 4 .