TiO_2/FePS_3 S-Scheme Heterojunction for Greatly Raised Photocatalytic Hydrogen Evolution

摘要

The aggravating extreme climate changes and natural disasters stimulatethe exploration of low-carbon/zero-carbon alternatives to traditional carbonbasedfossil fuels. Solar-to-hydrogen (STH) transformation is considered asappealing route to convert renewable solar energy into carbon-free hydrogen.Restricted by the low efficiency and high cost of noble metal cocatalysts,high-performance and cost-effective photocatalysts are required to realizethe realistic STH transformation. Herein, the 2D FePS_3 (FPS) nanosheetsanchored with TiO_2 nanoparticles (TiO_2/FePS_3) are synthesized and testedfor the photocatalytic hydrogen evolution reaction. With the integration ofFPS, the photocatalytic H_2-evolution rate on TiO_2/FePS_3 is radically increasedby ≈1686%, much faster than that of TiO_2 alone. The origin of the greatlyraised activity is revealed by theoretical calculations and various advancedcharacterizations, such as transient-state photoluminescence spectroscopy/surface photovoltage spectroscopy, in situ atomic force microscopy combinedwith Kelvin probe force microscopy (AFM-KPFM), in situ X-ray photoelectronspectroscopy (XPS), and synchrotron-based X-ray absorption near edge structure.Especially, the in situ AFM-KPFM and in situ XPS together confirm theelectron transport pathway in TiO_2/FePS_3 with light illumination, unveilingthe efficient separation/transfer of charge carrier in TiO_2/FePS_3 step-schemeheterojunction. This work sheds light on designing and fabricating novel 2Dmaterial-based S-scheme heterojunctions in photocatalysis.