Novel noble-metal-free NiCo-LDH/CdSe S-type heterojunction with built-in electric field for high-efficiency photocatalytic H2 production

Abstract

BackgroundConstructing heterojunction is one of the effective strategies for boosting carrier separation. Although CdSe is an excellent photocatalytic material, its activity is still very low. MethodsIn this paper, NiCo-LDH/CdSe (NCCSe) binary heterojunctions were successfully prepared by a two-step hydrothermal method. The results of photocatalytic tests show that 12NCCSe composites have the highest photocatalytic H2 production activity, with an average rate of 2929.4 μmol·g−1·h−1, which is 74 times higher than that of pure CdSe (39.5 μmol·g−1·h−1). Significant findingsThere are two main reasons for the obvious improvement of photocatalytic activity. Firstly, the separation efficiency of photogenerated carriers is greatly improved, which is attributed to the formation of S-type heterojunction with built-in electric field. Secondly, the addition of NiCo-LDH greatly enhances the light absorption intensity of NCCSe composites, providing more photogenerated electrons. In addition, the mechanism of increased photocatalytic activity for NCCSe S-type heterojunction composites was further discussed. This work provides a thought for constructing NiCo-LDH-based S-type heterojunction for efficient photocatalytic H2 production, which could easily extend to other LDHs materials.