报告摘要：

Semiconductor photocatalysts have been widely used for photochemical water splitting, purification of organic contaminants, and bacterial detoxification. However, most photocatalysts suffer greatly from photocorrosion under visible light irradiation. Here we report a viable strategy to markedly improve photocorrosion resistance of photocatalysts by draping ultrathin yet highly impermeable graphene layers over a semiconductor CdS electrode. Remarkably, the average lifetime of three-layer-graphene-draped CdS photocatalyst is prolonged by 8 times compared to as-prepared CdS counterpart without graphene draping. The introduction of graphene layers largely suppresses the charge carrier recombination of CdS film and decreases the carrier transfer resistance at the interface, thereby leading to increased photocurrent and enhanced photocatalytic performance. Our DFT calculations also show that electrons are readily transferred from CdS to graphene, correlating well with the PL measurement.

The photocorrosion is mainly caused by oxidation reaction between CdS and O₂ and H₂O assisted with photo-generated holes. The draped graphene effectively prevents the direct contact between CdS film and O₂and H₂O, thus considerably retarding the photocorrosion of CdS upon visible light exposure. This simple yet robust graphene-draping strategy for anti-photocorrosion of semiconductor photocatalysts is environmentally friendly as it prevents them from entering into surrounding environment, thus eliminating the possible secondary pollution [1].

[1] Mengye Wang, and Yang Chai*, et al. Journal of the American Chemistry Society, 2017, 139(11), 4144-4151.

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