Designing heterostructure photocatalysts is a promising approach for developing highly efficient photocatalysts for hydrogen energy production. In this work, we synthesized a series of a covalent organic framework (COF)/g-C3N4 (CN) heterojunction photocatalysts, denoted asx% COF/CN (in whichxindicates the weight % of COF andx=5, 10, 20, 30, 40, 50, 90, 95, 100), for hydrogen production. The COF, which is a key component of the photocatalyst, was prepared by assembling benzothiadiazole (BT) and pyrene (Py) derivatives as building blocks. Integrating COF rods into the two-dimensional (2D) layered g-C3N4 structure significantly improved photocatalytic H2 production. The hybrid system (30% COF/CN) displayed an outstanding hydrogen evolution rate (HER) of 27540±805μmolg-1h-1, outperforming most known COFs and g-C3N4-based photocatalysts, besides exhibiting stable photocatalytic performance. Moreover, the apparent quantum yield (AQY) was 15.5±0.8% at 420nm. Experimental techniques and density functional theory (DFT) calculations demonstrated that the 30% COF/CN heterostructure has broad visible-light absorption, adequate band energy levels, and the best chemical reactivity descriptors compared to the individual components, resulting in effective carrier separation and excellent performance. Our findings offer a valuable strategy for developing highly efficient and stable heterojunction photocatalysts for visible-light-driven H2 evolution.
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