Gel-assisted synthesis of CIZS for visible-light photocatalytic reduction reaction

ZnS-CuInS2 (CIZS) solid solution is synthesized via a chitosan gel-assisted method. The bandgap of the obtained CIZS semiconductor is 1.68 eV, and the position of the flat potential is 0.86 eV. When Ru is selected as the cocatalyst, the photocatalytic hydrogen evolution rate of CIZS@Ru reaches 4.86 mmol g- 1h- 1 under visible-light (lambda>420 nm) radiation, and it presents good stability. Besides, CIZS@Ru also shows good CO2 reducibility, where the product contains hydrogen, methane, and a small amount of formate. The photoelectrochemical tests also suggest that Ru is the optimum cocatalyst compared with Rh, Pt and Ni. Meanwhile, the internal mechanism of photogenerated charge transfer between semiconductors and cocatalyst has been revealed by the band bending concept. This work provides a novel and facile strategy to fabricate p-type CIZS semiconductor with high visiblelight photocatalytic reduction performance.

Automated summary

ZnS-CuInS2 (CIZS) solid solution was synthesized via a chitosan gel-assisted method, with the obtained CIZS@Ru showing excellent photocatalytic hydrogen evolution performance and good stability under visible light irradiation, along with good CO2 reducibility. The study revealed the internal mechanism of Ru as the optimum cocatalyst.