Covalent Grafting of a Nickel Thiolate Catalyst onto Covalent Organic Frameworks for Increased Photocatalytic Activity

Abstract Covalent organic frameworks (COFs) have recently emerged as prospective photoactive materials with noble Pt as a cocatalyst for photocatalytic hydrogen evolution. In this work, a series of SH‐group‐functionalized covalent organic frameworks, TpPa‐1‐SH‐X, is prepared by reaction of p‐phenylenediamine (Pa) and 1,3,5‐triformylphloroglucinol (Tp) with p‐NH2C6H4SH as a modulating agent. The reaction of TpPa‐1‐SH‐X with NiII acetylacetonate Ni(acac)2 gave nickel thiolate‐immobilized TpPa‐1 (TpPa‐1‐SNi‐X). The highest hydrogen evolution rate was 10.87 mmol h−1 g−1, which was an enhancement of 16.47, 3.83, and 1.84 times than that of the parent TpPa‐1, covalent‐bond‐free [(p‐NH2C6H4S)2Ni]n/TpPa‐1‐SH‐10, and 3 wt % Pt‐deposited TpPa‐1, respectively. This enhanced photocatalytic hydrogen evolution is ascribed to enhanced crystallinity, the use of NiII thiolate as a cocatalyst and covalent bonding between the cocatalyst and TpPa‐1.