Supramolecular Cage-Based Heterojunction: Chloroplast Mimicked Artificial Photosynthesis for Efficient Ethanol Production.

Photosynthesis of C2+ products like ethanol through artificial photosynthetic overall reaction is much desired yet generally challenged by spatial confinement/utilization of C1 intermediates or kinetically sluggish C─C bond coupling in the complex multi-electronic reduction processes. Inspired by nature, a supramolecular biomimetic heterojunction (Zn-TIPP/CdS) photocatalyst was designed by mimicking chloroplasts. The coupling of the unique supramolecular cage structure of Zn-TIPP with CdS in this heterojunction successfully simulates the comprehensive functions of stroma and grana in chloroplasts, achieving one of the highest ethanol production rates (138.9 µmol g-1 h-1, 93% selectivity) via artificial photosynthesis, which significantly surpasses most previously documented photocatalysts. Driven by the fast charge transfer efficiency in the biomimetic heterojunction, the spatial confinement and multisite catalytic effects of the supramolecular cage in Zn-TIPP enable the cascade conversion of CO2 into ethanol as revealed by in situ characterizations and theoretical calculations. The establishment of such redox heterojunction would promote the design of efficient photocatalysts for the generation of value-added fuels through artificial photosynthetic overall reaction.