Z-type heterojunction Pt/Zn0.2Cd0.8S/Cs3PW12O40: Mitigating photocorrosion, leveraging photochromism, and efficient photocatalytic hydrogen evolution

Catalysts are key components in the photocatalytic hydrogen precipitation process. However, commonly used catalysts such as sulfides, suffer from severe photogenerated carrier recombination and photocorrosion. To address this problem, in this work, Cs₃PW₁₂O₄₀, polyoxometalates with reversible photochromic effect, and Zn_0.2Cd_0.8S with photocorrosivity are constructed to form a Z-type heterojunction to facilitate the separation of photogenerated carriers, and at the same time synergize with the unique photochromic effect of Cs₃PW₁₂O₄₀ to mitigate photocorrosion. Moreover, by introducing the co-catalyst Pt to form a Schottky barrier, which further promotes the separation of photogenerated carriers, the Pt/Zn_0.2Cd_0.8S/Cs₃PW₁₂O₄₀ Z-type heterojunction ternary composites were finally rationally designed and applied to photocatalytic hydrogen precipitation for the first time. The photocatalytic hydrogen precipitation rate of the optimal heterojunction composite was 10.4 mmol/g/h, and its apparent quantum efficiency at a single wavelength of 420 nm could reach 8.15 %. Therefore, this study provides a new strategy for alleviating the photocorrosion of sulfides and the application of polyoxometalates in photocatalytic hydrogen precipitation.