La₂O₃‐Modified LaTiO₂N Photocatalyst with Spatially Separated Active Sites Achieving Enhanced CO₂ Reduction

Activating CO 2 molecule and promoting proton release from kinetically sluggish water oxidation are two important half‐reaction processes for achieving efficient solar‐driven conversion of CO 2 to fuels. Here, an effective route is proposed that uses a solid base to modify photocatalyst with defects, aiming to simultaneously accelerate the two reaction processes. To verify this hypothesis, the La 2 O 3 is decorated on surface of LaTiO 2 N with oxygen vacancies, achieving a twofold increase in CH 4 yield rate for CO 2 reduction. The prominent activity results from the following two effects: (1) The O 2− in La 2 O 3 as basic sites favors CO 2 chemisorption in the form of CO 3 2− species, greatly contributing to both the bending of OCO bond and the decrease of the lowest unoccupied molecule orbit energy of CO 2 molecule. (2) The oxygen vacancies on LaTiO 2 N are beneficial in activating H 2 O to adsorbed OH, thus effectively decreasing the reaction barriers of water oxidation to release protons. The design concept of simultaneously activating the CO 2 and H 2 O at different spatial sites may offer a new strategy to suppress the reverse reactions for efficient solar energy conversion.