Band Alignment of WS2/MoS2 Photoanodes with Efficient Photoelectric Responses based on Mixed Van der Waals Heterostructures

Band alignment based on mixed van der Waals heterostructures is vital to design new types of photoanodes based on transition metal dichalcogenides. Herein, different mixed ratios of WS 2 /MoS 2 photoanodes are made using a liquid‐phase exfoliation method. The WS 2 /MoS 2 photoanode is characterized by high‐resolution X‐ray photoelectron spectroscopy, which suggests type‐II heterostructure with a conduction band offset of 0.54 eV and a valence band offset of 0.55 eV. Herein, it is observed that the maximum photocurrent density at the ratio WS 2 /MoS 2 (1:1) is eight times and four times larger than pure WS 2 and MoS 2 , respectively. The amperometric I – t , Mott–Schottky, and Nyquist measurements are used to analyze the photoelectric enhancement, which suggests efficient charge separation in the photoelectrodes and low electrode–electrolyte interface resistance. Raman spectroscopy and X‐ray diffraction spectroscopy with the mode shift confirm the charge transfer and lattice change in the mixed heterostructure. The charge density difference of WS 2 /MoS 2 also confirms charge redistribution after heterostructure formation to accelerate charge transfer at the heterostructure interface efficiently. Herein, a cheap and easy way to design WS 2 /MoS 2 heterojunction‐based photoanodes for photoelectrochemical devices is explained.