Decoupled Artificial Photosynthesis via a Catalysis-Redox Coupled COF||BiVO<sub>4</sub> Photoelectrochemical Device
Wan Lin, Jing Lin, Xiang Zhang, Linlin Zhang, Rahul Anil Borse, Yaobing Wang
Abstract
Artificial photosynthesis is an attractive approach to direct fuel production from sunlight. However, the simultaneous O 2 evolution reaction (OER) and CO 2 reduction reaction (CDRR) present challenges for product separation and safety. Herein, we propose a strategy to temporally decouple artificial photosynthesis through photoelectrochemical energy storage. We utilized a covalent organic framework (DTCo-COF) with redox-active electron donors (−C–OH moieties) and catalytically active electron acceptors (cobalt-porphyrin) to enable reversible −C–OH/–C═O redox reaction and redox-promoted CO 2 -to-CO photoreduction. Integrating the COF photocathode with an OER photoanode in a photoelectrochemical device allows the effective storage of OER-generated electrons and protons by −C═O groups. These stored charges can be later employed for CDRR while regenerating −C═O to complete the loop, thus enabling on-demand and separate production of O 2 or solar fuels. Our work sets the stage for advancements in decoupled artificial photosynthesis and the development of more efficient solar fuel production technologies.