Dynamic Reconstruction of Photoswitchable Bismuth Molybdate for Solar-Driven CO₂ Reduction

The investigation of the photothermal synergistic reaction mechanism remains a significant challenge due to the intricate surface reconstruction processes under the multifield coupling of optical and thermal fields. Dynamic reconstruction of active sites is key to unlocking the potential for efficient catalytic reactions under real-world conditions. Herein, we present in situ technologies by capturing the dynamic behavior of photothermal active sites in real-time, offering insight into their role in photothermal catalysis. Specifically, we study the formation of a photoswitchable Bi^(3-δ)+ site, which is generated via single-electron injection at the Bi³⁺ site upon photolysis of the Bi-O bond. This site undergoes a recyclable cycle of "photoswitchable formation─single-electron transfer─self-healing filling", which not only facilitates efficient electron exchange with CO₂ but also significantly enhances the overall catalytic performance. The near-infrared (NIR) light-induced thermocontrolled transition of trapped electrons in the Bi 6p shallow donor state significantly promotes electron injection into *COOH, accelerating its dissociation. This mechanism, identified as the photothermal synergy, accounts for the 5-fold increase in catalytic activity (221.4 μmol/(g·h)) observed with the photoactivated Bi₂MoO₆ catalyst. These findings offer a perspective on the dynamic behavior of active sites and provide valuable insights into the design of next-generation photocatalysts for efficient CO₂ conversion under complex photothermal conditions.