Harnessing interfacial π–d conjugation in covalently linked COFs with amine-Zn0.4Cd0.6S strengthens photoinduced charge transfer for photocatalysis

Abstract

This study focuses on the effective enhancement of photocatalytic activity by strategically combining inorganic and organic semiconductors in a heterojunction. The challenge lies in seamlessly integrating these disparate components. In this research, we successfully fabricated inorganic–organic bridged heterojunctions between COF (Covalent Organic Framework) and metal sulfides, linked by stable covalent bonds. This approach led to efficient photocatalytic hydrogen (H2) evolution from water (H2O), marking a significant milestone. Comparing the performance of our ZCS-COF hybrids to the individual constituents, i.e., pure TpPa-1-COF and amine-Zn0.4Cd0.6S (ZCS), we observed a remarkable improvement in photocatalytic efficiency under visible light irradiation. Particularly noteworthy is the ZCS-COF-20 hybrid, which exhibited an impressive photocatalytic H2 production rate of 11.3 mmol g-1h−1. This rate is tenfold higher than that of the pristine TpPa-1-COF. This enhancement can be attributed to the interfacial π-d conjugation effects within the heterojunction. These effects facilitate the transfer of electrons from the metal sulfide to COFs via covalent bonds, ensuring efficient charge separation and transfer. Consequently, the resulting hybrid exhibits exceptional photocatalytic activity and stability.