Constructing highly dispersed 0D Co₃S₄ quantum dots/2D g-C₃N₄ nanosheets nanocomposites for excellent photocatalytic...

The development of noble-metal-free catalysts with high efficiency photocatalytic properties is critical to the heterogeneous catalysis. Herein, zero-dimensional (0D) metal sulfide quantum dots/two-dimensional (2D) g-C₃N₄ nanosheets (Co₃S₄/CNNS) nanocomposites are synthesized by a two-step method, including the ways of in-situ deposition and water bath. The highly dispersed Co₃S₄ quantum dots (particle size is 2-4 nm) are evenly and tightly fixed on CNNS, which can be used as co-catalyst to effectively replace noble metals to improve the photocatalytic properties of CNNS. Co₃S₄/CNNS-900 has the apparent quantum efficiency, which is up to 7.85% at 400 nm. At the same time, the H₂ evolution rate of Co₃S₄/CNNS-900 is 20,536.4 μmol g^-1 h^-1, which is 555 times than CNNS. The excellent photocatalytic performance is due to the highly dispersed Co₃S₄ quantum dots on 2D CNNS, which facilitate the formation of more active sites, Co₃S₄/CNNS promotes the separation and migration of photogenerated carriers, shortens the migration distance of photogenerated carriers, and eventually leads to an increase of the photocatalytic performance.