Sulfur-doped g-CN nanosheets for photocatalysis: Z-scheme water splitting and decreased biofouling.

In this study, an S-doped g-CN nanosheet was prepared as a photocatalyst for effective oxygen evolution reaction. Sulfur plays a crucial role in S-doped g-CN not only in increasing the charge density but also in reducing the energy band gap of S-doped g-CN via substitution of nitrogen sites. S-doped g-CN can serve as an oxygen-evolved photocatalyst, when combined with Ru/SrTiO:Rh in the presence of [Co(bpy)] as an electron mediator, enables photocatalytic overall water splitting under visible light irradiation with hydrogen and oxygen production rates of 24.6 and 14.5 μmol-h, respectively. Moreover, the photocatalytic overall water splitting to produce H and O using this Z-scheme system could use for five runs to at least 94.5 h under visible light irradiation. On the other hand, S-doped g-CN can reduce biofouling by bacteria such as Escherichia coli by more than 70%, by simply incubating the S-doped g-CN sample with bacterial solution under light irradiation. Our results suggest that S-doped g-CN is a potentially effective, green, and promising material for a variety of photocatalytic applications.