Rapid Surface Reconstruction of In2S3 Photoanode via Flame Treatment for Enhanced Photoelectrochemical Performance.

Abstract

Surface reconstruction, re-organizing the surface atoms or structure, is a promising strategy to manipulate materials' electrical, electrochemical, and surface catalytic properties. Herein, we demonstrate a rapid surface reconstruction of indium sulfide (In2S3) via a high-temperature flame treatment to improve its charge collection properties. The flame process selectively transforms the In2S3 surface into a diffusionless In2O3 layer with high crystallinity. Additionally, it controllably generates bulk sulfur (S) vacancies within a few seconds, leading to surface-reconstructed In2S3 (sr-In2S3). When using those sr-In2S3 as photoanode for photoelectrochemical (PEC) water splitting devices, these dual functions of surface In2O3/bulk In2S3 reduce the charge recombination in the surface and bulk region, thus improving photocurrent density and stability. With optimized surface reconstruction, the sr-In2S3 photoanode demonstrates a significant photocurrent density of 8.5mA/cm2 at 1.23V versus a reversible hydrogen electrode (RHE), marking a 2.5-fold increase compared to pristine In2S3 (3.5mA/cm2). More importantly, the sr-In2S3 photoanode exhibited an impressive photocurrent density of 7.3mA/cm2 at 0.6V versus RHE for iodide oxidation reaction (IOR). We also showcase a practical and scalable surface reconstruction via flame treatment. Our work provides new insights for surface reconstruction engineering in sulfide-based semiconductors, making a breakthrough in developing efficient solar-fuel energy devices. This article is protected by copyright. All rights reserved.