Acid-Exfoliated Metallic Co0.85Se Nanosheets as Cocatalyst on Cd0.5Zn0.5S for Photocatalytic Hydrogen Evolution under Visible-Light Irradiation

Co0.85Se, nonstoichiometric phase, as an excellent electrocatalytic activity, was used as a cocatalyst to modify Cd0.5Zn0.5S nano-photocatalyst. The Co0.85Se (1.5 wt %)/Cd0.5Zn0.5S Schottky junction shows the greatest activity for H2 generation (759.3 μmol h–1), which is 2.1 times that of bare Cd0.5Zn0.5S (350.6 μmol h–1). It turns out that Co0.85Se nanoplates can be exfoliated into nanosheets by diluted hydrochloric acid. It is noted that exfoliated metallic Co0.85Se nanosheets show a little better hydrogen evolution reaction property and a smaller charge-transfer resistance than those of Co0.85Se nanoplates, implying that exfoliated Co0.85Se nanosheets have more active sites and higher electrical conductivity. The distinct properties of exfoliated metallic Co0.85Se nanosheets enhance the efficient spatial separation of photoinduced charged particle carriers and result in an excellent enhancement in the photoelectric current and photocatalytic hydrogen evolution performance of Cd0.5Zn0.5S. The amount of Co0.85Se in the heterojunction has an obvious effect on the hydrogen evolution property. The consequences show that 1.5 wt % exfoliated Co0.85Se nanosheets added into the Cd0.5Zn0.5S sample result in the maximum water splitting rate of 759.3 μmol h–1. For other semiconductor photocatalyst systems, our work demonstrates that introducing exfoliated metallic Co0.85Se nanosheets electrocatalyst as an efficient cocatalyst to improve photocatalytic capacity without noble metals is feasible.