Engineering the Charge Density on an In 2.77 S 4 /Porous Organic Polymer Hybrid Photocatalyst for CO 2 -to-Ethylene Conversion Reaction.

The development of an efficient photocatalyst for C2 product formation from CO 2 is of urgent importance toward the deployment of solar-fuel production. Here, we report a template-free, cost-effective synthetic strategy to develop a carbazole-derived porous organic polymer (POP)-based composite catalyst. The composite catalyst is comprised of In 2.77 S 4 and porous organic polymer (POP) and is held together by induced-polarity-driven electrostatic interaction. Utilizing the synergy of the catalytically active In centers and light-harvesting POPs, the catalyst showed 98.9% selectivity toward the generation of C 2 H 4 , with a formation rate of 67.65 μmol g -1 h -1 . Two different oxidation states of the In 2.77 S 4 spinel were exploited for the C-C coupling process, and this was investigated by X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and density functional theory (DFT) calculations. The role of POP was elucidated via several photophysical and photoelectrochemical studies. The electron transfer was mapped by several correlated approaches, which assisted in establishing the Z-scheme mechanism. Furthermore, the mechanism of C 2 H 4 formation was extensively investigated using density functional theory (DFT) calculations from multiple possible pathways.