Perovskite hydroxide ZnSn(OH) ₆ ‐derived three‐dimensional flower‐like SnS ₂ /Bi ₂ S ₃ heterojunction for sensitive photoelectrochemical detection of Cr(VI)

Abstract The genetic toxicity and carcinogenic activity of Cr(VI) make the development of highly efficient and sensitive methods critically important. Photoelectrochemical (PEC) sensing, which can detect heavy metals coexisting in the environment, is an emerging strategy for detecting Cr(VI). To improve the sensitivity of the PEC sensors, SnS 2 was employed to construct a SnS 2 /Bi 2 S 3 heterojunction for sensitive PEC detection of Cr(VI). Consequently, a three‐dimensional (3D) flower‐like SnS 2 was synthesized via the hydrothermal sulfidation of perovskite hydroxide ZnSn(OH) 6 cubes with the assistance of ethylene diamine tetraacetic acid to remove Zn 2+ . Subsequently, via a simple successive ionic layer adsorption and reaction method, Bi 2 S 3 was generated in situ on the SnS 2 surface, and a 3D flower‐like SnS 2 /Bi 2 S 3 heterojunction was prepared. Based on the designed 3D morphology, large surface area, multiple active sites, and matched energy levels of SnS 2 /Bi 2 S 3 heterojunction, the PEC performance has been promoted effectively for sensitive detection of Cr(VI), acquiring a broad linear range (0.01–100 μM) and a low detection limit (4.3 nM). Furthermore, the stability, selectivity, and reproducibility of the prepared PEC sensors were at practical levels, highlighting considerable potential for applications in environmental monitoring.