Optimized the Carrier Transport Path and Separation Efficiency of 2D/2D Heterojunction in Photoelectrochemical Water Splitting

Abstract

AbstractIt is a promising strategy that the photoelectrode with high charge transfer rate and separation efficiency is designed in the photoelectrochemical (PEC) water splitting. Herein, the nanoflakes/nanoflakes (2D/2D) MoS2/ZnIn2S4 heterojunction is synthesized by two‐step hydrothermal methods. The carrier transport path in heterojunction is optimized through the Schottky contact calculated by density functional theory (DFT) and large specific surface area between 2D nanoflakes MoS2 and ZnIn2S4. Besides, the bimetallic oxyhydroxide NiFeOOH can be used as co‐catalyst to improve the separation of carriers. The results exhibit that MoS2/ZnIn2S4/NiFeOOH photoelectrode with dramatically enhanced photocurrent density of 0.74 mA/cm2 at 1.23 V versus the reversible hydrogen electrode (VRHE), which is 2.6 and 5.7 times higher than the bare MoS2 and ZnIn2S4, respectively. And it has the largest charge separation efficiency (ηbulk) (22.8 %) and charge transfer efficiency (ηsurface) (64.6 %) in the as‐prepared samples. This work provides a strategy for design of the photoelectrode with excellent charge transfer efficiency and separation efficiency in PEC water splitting.