Photo-thermal coupling to enhance CO₂ hydrogenation toward CH₄ over Ru/MnO/Mn₃O₄.

Abstract

Upcycling of CO₂ 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/Mn₃O₄ for photo-thermal catalytic CO₂ hydrogenation to CH₄, which is the result of a combination of external heating and irradiation. Remarkably, under relatively mild conditions of 200 °C, a considerable CH₄ production rate of 166.7 mmol g^-1 h^-1 was achieved with a superior selectivity of 99.5% at CO₂ conversion of 66.8%. The correlative spectroscopic and theoretical investigations suggest that the yield of CH₄ 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 CO₂ hydrogenation toward CH₄.