This study introduces a WC quantum dot decorated defective ZnIn2S4 nanosheets (DZIS/WCQDs) photocatalyst, which achieves synergistic enhancement of photocatalytic water splitting coupled with benzyl alcohol oxidation. It is demonstrated that the unique Schottky junctions and photothermal effect significantly promote the separation and transport of photogenerated carriers. The low concentration ·OH and photogenerated holes further improve benzaldehyde conversion rate and selectivity.
Abstract
As is well known, there are problems such as low utilization rate of photogenerated holes and resource consumption of sacrificial agent in solar-driven photocatalytic water splitting to hydrogen technology. Herein, WC quantum dots decorated defective ZnIn2S4 nanosheets (DZIS/WCQDs) dual-functional photocatalysts are fabricated. Its unique Schottky junctions and photothermal effect significantly promote the separation and transport efficiency of photogenerated carriers, as well as achieving synergistic enhancement of photocatalytic water splitting coupled with selective oxidation of benzyl alcohol (BA). Moreover, the photothermal effect can slowly induce the decomposition of H2O2 to produce ·OH, and the low concentration ·OH and photogenerated holes continuously generated in situ can directly and rapidly attack the αC─H bond of BA to improve benzaldehyde (BAD) conversion rate and selectivity. Consequently, DZIS/WCQDs composites exhibit a surprising conversion rate and selectivity of 85.34% and 96.53% for BAD, and outstanding H2 and BAD evolution rates of 12.58 and 10.53 mmol g−1 h−1 without sacrificial agent and co-catalyst. Notably, combining the production rate and selectivity of products, the DZIS/WCQDs is the optimal catalyst material at present. This work opens up a green and carbon free effective path to solve the problems of low efficiency and high cost of photocatalytic hydrogen production.
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