Bioinspired charge reservoir enables efficient CO2 photoreduction with H2O via tungsten valence oscillation

Solar-driven conversion of CO2 and H2O into chemicals is a promising strategy, while achieving simultaneous and efficient CO2 reduction and H2O oxidation remains challenging. Here, inspired by the role of plastoquinone in temporarily storing electrons during natural photosynthesis, we design a silver-modified tungsten trioxide (Ag/WO3) that functions as a charge reservoir through reversible W6+/W5+ transitions under irradiation. When coupled with various active components, Ag/WO3 significantly enhances their CO2 conversion performance, indicating the universality of this strategy. Specifically, coupling Ag/WO3 with cobalt phthalocyanine (CoPc), the CoPc/Ag/WO3 catalyst achieves a CO production rate of ~1.5 mmol gCoPc−1 h−1, representing a 100-fold enhancement over pure CoPc. Mechanistic studies reveal that electrons stored in Ag/WO3 efficiently scavenge photogenerated holes from CoPc, thereby maintaining a high electron density at CO2 reduction sites of CoPc. This work establishes a bioinspired charge reservoir strategy for efficient CO2 photoreduction, providing a universal approach to solar fuel production. Solar-driven conversion of CO₂ and H₂O into chemicals is a promising strategy, yet achieving simultaneous and efficient CO₂ reduction and H₂O oxidation remains challenging. Here, the authors design silver-modified tungsten trioxide that acts as a charge reservoir via reversible W⁶⁺/W⁵⁺ transitions under irradiation, enabling efficient CO₂ photoreduction with H₂O.