Piezoelectric Effect Promoted Photoelectrochemical Water Splitting Ability of ZnIn2S4 Photoanode with Highly Exposed Active (110) Facets

Abstract It is important to design high performance photoelectrode materials in the process of photoelectrochemical (PEC) water splitting. Herein, ZnIn 2 S 4 nanomaterial with highly exposed active (110) facets were prepared by a simple hydrothermal method. Meanwhile, piezoelectric polarization was used to induce the generation of built‐in electric field, which can suppress the compounding of photogenerated charge carriers caused by structural defects at the semiconductor surface. By controlling the crystal facet structure, ZnIn 2 S 4 with a highly exposed active (110) facet shows a better photoelectrochemical water splitting performance under ultrasound, and its photocurrent density increases with the increase of ultrasound frequency, reaching a maximum value of 0.36 mA/cm 2 at 1.23 V RHE , which is 2.8 times higher than that without ultrasound. It can be concluded that the (110) facet of ZnIn 2 S 4 can induce a larger internal piezoelectric potential which allows rapid electron transer at the ZnIn 2 S 4 surface, under ultrasonic conditions. And the highly exposed (110) facet also provides more reactive sites, leading to further enhanced catalytic activity. Such nanomaterial with highly exposed active facets will provide inspiration for the construction of photoelectrode systems with high photoelectrochemical water splitting efficiency.