Reconfigurable Charge Transfer Between Type‐II and Z‐Scheme in WO 3 /Cu 2 O for All‐Day Photoreduction of CO 2

ABSTRACT Solar‐driven CO 2 conversion to high‐value chemicals provides a sustainable solution to energy and climate challenges, but its practical use is limited by sunlight intermittency. Since photocatalytic CO 2 reduction relies on photogenerated electrons, sustaining electron supply in darkness is key to all‐day photocatalysis. Inspired by battery charging/discharging, we designed a WO 3 /Cu 2 O catalyst with dynamic heterojunction reconfiguration. After 15 min of irradiation, it stores up to 16.81 C· of charge, released in darkness. Mechanistic studies reveal that during the reaction process, the valence state transition of W (W 6+ →W 5+ ) enables the WO 3 /Cu 2 O catalyst to dynamically reconfigure between Type‐II and Z‐scheme heterojunctions, realizing photogenerated charge storage and release, thereby enabling a continuous catalytic process under dark conditions and achieving all‐day photocatalysis. This work overcomes the dependence of continuous illumination in traditional photocatalysis, laying a theoretical foundation for the practical application of photocatalytic CO 2 reduction.