Anchoring MnWO4 Nanorods on LaTiO2N Nanoplates for Boosted Visible Light-Driven Overall CO2 Reduction.

Abstract

The photocatalytic conversion of CO2 into hydrocarbon fuel holds immense potential for achieving a carbon closed loop and carbon neutrality. Developing efficient photocatalysts plays a pivotal role in enabling the widespread application of photocatalytic CO2 reduction on a large scale. Herein, a novel S-scheme MnWO4/LaTiO2N heterojunction composite is successfully synthesized by a hydrothermal method. This composite catalyst demonstrates excellent photocatalytic activity in the reduction of CO2 to CO and CH4 using water molecules as electron donors under visible light irradiation, and the optimized 30% MnWO4/LaTiO2N composite displays significantly enhanced CO and CH4 yields of 3.94 and 0.81 μmol g-1 h-1, respectively, and the corresponding utilized photoelectron number reaches 14.7 μmol g-1 h-1, which is approximately 7.7 and 12.9 times that of LaTiO2N and MnWO4. The enhancement in photocatalytic activity of the composites can be ascribed to the construction of an S-scheme heterojunction, which exhibits improved charge transfer dynamics, retains the strongest redox capacity, and effectively suppresses back reactions. In situ Fourier-transform infrared imaging provides evidence, to a certain extent, for the existence of a temporal gradient order in the generation of multiple products during the photocatalytic reduction of CO2.