Phase engineering to construct In2S3 heterophase junctions and abundant active boundaries and surfaces for efficient Pyro-PEC performance in CdS/In2S3

Abstract

Metal sulfide photoelectrodes are considered as common catalysts for PEC water splitting, but their instability and carrier density limitations still restrict their applications. Phase modification plays a vital role in improving photocatalytic efficiency. Here, we successfully constructed In₂S₃ heterophase junctions in CdS/In₂S₃ heterojunctions by phase modulation engineering for efficient pyro-photoelectrochemical catalytic (Pyro-PEC) water splitting. The experimental results show that the CdS/In₂S₃ generated by phase engineering displays a high current density of 3.52 mA cm⁻² at 1.23 V vs. RHE under the Pyro-PEC conditions, which is a 14.67-fold enhancement of bare CdS under the photoelectrocatalytic conditions, and exhibits a 63.98% bulk transport capacity, which is a 49.51% enhancement of bare CdS under photoelectrocatalytic conditions, and the stability also improved very well. This is due to the fact that photoelectrodes with heterojunctions and heterophase junctions formed abundant phase boundaries and active surfaces to promote catalytic reactions, and enhanced the polarization force to optimize the pyroelectric performance, which ultimately achieved excellent pyro-photoelectrochemical performance. This work provides evidence for the effect of phase engineering on photoelectric and pyroelectric properties, and provides a simple and effective method for modulating the phase structure for photoanodes using hydrothermal methods.