Highly efficient In2S3 nanosphere decorated WO3/Bi2WO6 dual heterostructure nanoflake arrays for enhanced low bias watersplitting under visible light irradiation

Abstract

Highly efficient visible light excitation and generating high photogenerated charges in semiconductor electrodes yet challenging in photoelectrochemical (PEC) water splitting. Herein, dual heterojunctions comprising of WO3/Bi2WO6 2D nanoflakes surrounded by In2S3 nanosphere photo absorbers used as a photoelectrodes. Under visible light irradiation, the WO3/Bi2WO6/In2S3 photoelectrode produced an excellent low overpotential-photocurrent. The photocurrent density of 4.02 mA/cm2 at 0.84 V vs. RHE was achieved for a heterostructure photoanode and 8-fold higher than WO3 photoanode. The incident photon to the current conversion efficiency of WO3/Bi2WO6/In2S3 (52% at 400 nm) is about 8 fold higher that of WO3. The improved hydrogen evolution performance was attained through hindering recombination and better band alignment between In2S3 and Bi2WO6. The low charge transfer resistance (152.8 Ohm) of WO3/Bi2WO6/In2S3 photoanode substantially improves the surface charge separation through In2S3 photoactivated catalytic sites. The WO3/Bi2WO6/In2S3 photoanode demonstrates an outstanding charge carriers lifetime, resulting in a maximum photocurrent density of 4.02 mA/cm2 for stable water splitting applications.