High photocatalytic and photoelectrochemical performance of a novel 0D/2D heterojunction photocatalyst constructed by ZnSe nanoparticles and MoSe2 nanoflowers

Metal oxide photocatalysts have the disadvantages of large band gap and high internal resistance, and their photoelectrochemical properties are restricted. Metal selenides are generally characterized by narrow bandgap width, low internal resistance, high utilization rate of sunlight and superior photoelectrochemical performance. The ZnSe/MoSe2 heterostructure composite was successfully constructed by loading ZnSe nanoparticles onto MoSe2 nanoplates with three-dimensional flower-like structure. In this heterostructure composite, ZnSe nanoparticles are uniformly encapsulated by MoSe2 nanoplates, and the larger contact surface facilitates the transfer of carriers between heterojunction, while the three-dimensional flower structure of MoSe2 can transport and collect photogenerated carriers. This heterojunction composite has a full-band absorption capability of UV and visible light. Photocatalytic tests showed that the photocatalytic activity of the heterojunction photocatalyst was more than twice of MoSe2 and more than 4 times of ZnSe at the optimum ZnSe composite ratio, and photoelectric performance of that was 2.75 times of MoSe2. The results show that the photoelectrochemical performance of ZnSe/MoSe2 has been greatly improved, mainly because of the 0D/2D structure and band matching of ZnSe/MoSe2, so that the photogenerated electrons excited on the ZnSe conduction band can be transported to the conduction band of MoSe2, thereby improving the carriers' separation efficiency and photoelectrochemical performance.