Visible light-driven, selective CO2 reduction in water by In-doped Mo2C based on defect engineering

Abstract

An In-doped Mo2C (In@Mo2C-d) is described as a photocatalyst for efficient and selective CO2 reduction. It is prepared by a metal organic framework (MOF)-engaged approach combining ion exchange and carbothermal reduction and illustrates a self-core-shell nanoflower structure with rich defects. The photocatalyst performs visible light-driven CO2-to-CO reduction with 97.3% selectivity at 234.4 μmol g−1 h−1 in aqueous media. Physicochemical measurements - isotopic labelling, time-resolved photoluminescence, in situ FT-IR, density functional theory - have been used to probe the photocatalytic mechanism. The combined analyses show that electrons are localized at neighboring Mo sites with localized defects and the d-band center is closer to the Fermi level after In doping, beneficial for the photocatalysis. They also suggest that In@Mo2C-d can stabilize COOH* intermediates and facilitate CO* desorption. The results point to a previously unreported CO2 reduction photocatalyst based on molybdenum carbide in which reactivity is promoted by doping and defect engineering.