Electronic regulation of single-atomic Ti sites on metal hydroxide for boosting photocatalytic CO₂ reduction

Photocatalytic CO₂ reduction is considered a sustainable method to address energy and environmental issues by converting CO₂ into fuels and chemicals, yet the performance is still unsatisfactory. Single atom catalysts hold promising potential in photocatalysis, but the selection of metal species is still limited, especially in early transition metals. Herein, inspired by the structure of anatase TiO₂, single Ti sites were successfully incorporated into a metal hydroxide support for the first time via cationic defects, significantly enhancing the photocatalytic performance by more than 30 times (from 0.26 to 8.09 mmol g^-1 h^-1). Based on the theoretical calculation and in situ characterization, the enhancement of photocatalytic performance can be attributed to the regulation of the electronic structure by the introduction of atomically dispersed Ti sites, leading to stronger binding with intermediates and enhanced charge transfer.