Accelerated “Electron Converter” Characteristics of NiCo-LDH for a CdS-Carbide Photocatalytic System with a Dual Heterointerface

Accelerating the electron transfer and thus inhibiting recombination of photogenerated carriers hold paramount significance for photocatalytic solar hydrogen generation. Introducing an intermediate transition layer in the Schottky junction structure would modulate the Schottky barrier and thus enhance the separation efficiency of photogenerated carriers. Herein, we insert an efficient NiCo-layered-double-hydroxide (NiCo-LDH) lamina between molybdenum carbide-supported reduced graphene oxide (Mo2C/rGO, abbreviated as MG) and CdS, fabricating the sandwich composite CdS@NiCo-LDH@Mo2C/rGO (noted as CLMG) for photogenerated hydrogen. The inserted NiCo-LDH enables the dual heterogeneous interface phase of CdS/NiCo-LDH and NiCo-LDH/Mo2C and decreases the Schottky barrier of CdS/Mo2C, boosting the electron transfer of CLMG. In addition, the experiments and DFT calculations indicate that the work functions increase in the order of CdS < NiCo-LDH < Mo2C. Benefiting from the unique nanoarchitecture of the catalyst, the unidirectional cascade electron transport is realized following the order of CdS → NiCo-LDH → Mo2C with NiCo-LDH as an accelerated "electron converter", which eventually expedites the photogenerated electron transfer of CdS to Mo2C and boosts carrier separation as well as the hydrogen reduction of the integrated system, achieving a 135 times greater H2 production rate (58.07 mmol g–1 h–1) than pristine CdS (0.43 mmol g–1 h–1). Moreover, CLMG exhibits excellent durability.