Self-assembled transition metal chalcogenides@CoAl-LDH 2D/2D heterostructures with enhanced photoactivity for hydrogen evolution

Abstract

Transition metal chalcogenides (TMCs) have been well-established as ideal low-dimensional systems for photocatalytic hydrogen evolution. Strategies toward improving the activity of these TMC photocatalysts by crafting heterostructures have been intensively studied. In this study, a two-dimensional (2D) CoAl layered double hydroxide (CoAl-LDH) has been assembled on 2D TMCs (CdIn₂S₄, In₂S₃, and ZnIn₂S₄) to construct novel 2D/2D heterostructures by a facile electrostatic assembly method. The intimate interaction at the interface of hybrids and the suitable energy level alignment enable an efficient pathway for electron transfer to improve the photoactivity. Experimental results show that the photocatalytic activity of the CdIn₂S₄@CoAl-LDH hybrids for H₂ production is about 4.3 times higher than that of CdIn₂S₄ nanosheets under visible-light irradiation. The effect of 2D CoAl-LDH on enhancing the photoactivities of In₂S₃ and ZnIn₂S₄ by similarly constructing 2D heterostructures has also been determined. This work establishes a foundation to construct 2D TMC-based heterostructures using CoAl-LDH nanosheets toward enhanced photoredox activity.