Fabrication of a NiCo2O4/Zn0.1Cd0.9S p-n heterojunction photocatalyst with improved separation of charge carriers for highly efficient visible light photocatalytic H2 evolution

Photocatalytic hydrogen (H2) evolution is a greatly promising strategy for solar to H2 conversion. However, photocatalytic activity of single photocatalyst is limited due to the fast recombination of photogenerated charge carriers. Recently, various heterojunction photocatalysts have been constructed to improve photocatalytic activity. Herein, a novel NiCo2O4/Zn0.1Cd0.9S (NCO/ZCS) p-n heterojunction photocatalyst was fabricated via a simple calcination method. The optimized NiCo2O4 content is 3 wt%, and corresponding NCO/ZCS shows the maximum H2 evolution rate of 34.4 mmol g−1 h−1 under visible light irradiation, which is over 4.9 times higher than that of pure ZCS, and has the apparent quantum efficiency of 58.8% at 420 nm. The improved photoactivity of NCO/ZCS can be attributed to the construction of NCO/ZCS p-n heterojunction. In addition, a possible mechanism for photocatalytic H2 evolution of NCO/ZCS p-n heterojunction was proposed.