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 (H-2) evolution is a greatly promising strategy for solar to H-2 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 H-2 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 H-2 evolution of NCO/ZCS p-n heterojunction was proposed. (C) 2019 Elsevier B.V. All rights reserved.