Construction of 2D Bi2S3/CdS Nanosheet Arrays for Enhanced Photoelectrochemical Hydrogen Evolution

Abstract

2D Bi2S3/CdS nanosheet arrays have been constructed by a simple three-step method. Firstly, BiOI nanosheet arrays have been electrochemically grown on the surface of conductive FTO substrate and then converted into Bi2S3 nanosheet arrays by ion exchange. Finally, CdS was hydrothermally deposited onto the surface of Bi2S3 nanosheet arrays to form hybrid Bi2S3/CdS nanosheet arrays. The obtained hybrid heterojunction arrays have been used as photoanodes for photoelectrochemical hydrogen evolution and showed enhanced performance and prolonged stability. The photocurrent density of the elegant Bi2S3/CdS nanosheet arrays reaches 9.48 mA/cm2 at 1.23 VRHE under an illumination of 100 mW/cm2 from AM 1.5G sun simulator, which is more than ten times higher than that of the pure Bi2S3 nanosheet arrays and the photocurrent density does not decline obviously after 4 h of continuous operation. Ultimately, a rational mechanism is proposed to elucidate the high performance and excellent stability of Bi2S3/CdS nanosheet arrays for photoelectrochemical cells. To obtain nanosheet arrays: Arrays of Bi2S3/CdS nanosheets on a FTO substrate are synthesized by electrodeposition, ion exchange and hydrothermal process. The Bi2S3/CdS nanosheet photoanodes show better photoactive and photostability compared to bare Bi2S3 (CdS) nanosheets for photoelectrochemical splitting of water.