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

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.