Customizing Synchronous Charge Tunneling Photosystems Toward Solar CO2 Conversion

Abstract Solar‐driven CO2 conversion to high‐value‐added chemical fuels has been deemed as an emerging way of alleviating deteriorating energy depletion and greenhouse effect. Nevertheless, precise modulation of spatial vectorial charge migration/separation in CO2 artificial photosystem remains challenging due predominantly to the ultrashort charge lifetime, sluggish charge transfer kinetics, and ultra‐stable symmetry of CO2 molecules, rendering stimulation of CO2 adsorption, activation and reduction a grand challenge. Herein, we conceptually demonstrate the design of a novel semiconductor‐insulator‐cocatalyst charge tunneling photosystem via a layer‐by‐layer (LbL) assembly strategy, which involves progressive intercalation of dual ultrathin insulating polymer layers in‐between layered double hydroxides (LDHs) and transition metal chalcogenide (TMC). It is demonstrated for the first time unleash that electron‐hole pairs photoexcited over TMC can simultaneously tunnel through the insulating polymer interim layers, followed by holes trapping by terminal LDHs and directional electrons migration to the CO2 molecules absorbing on the polymers surface, synergistically boosting the charge separation and reinforcing the solar CO2 reduction. This work would open a shining frontier to strategically craft novel charge‐tunneling artificial photosystems and benefit the fundamental understanding on the CO2 photoreduction technology toward solar energy conversion.