Porous ZnIn2S4 with confined sulfur vacancies for highly efficient visible-light-driven photocatalytic H2 production

Abstract

Ternary ZnIn₂S₄ (ZIS) chalcogenide is regarded as a promising candidate for photocatalytic hydrogen production performance; however, its activity is limited by the low separation efficiency and poor migration ability of photoexcited charge carriers. Herein, porous ZnIn₂S₄ photocatalysts with confined sulfur vacancies were successfully fabricated, alleviating the above issues that impair the hydrogen evolution rate. Due to the pore structure, the charge transfer diffusion pathway is greatly shortened. Furthermore, the sulfur vacancies can serve as electron trapped centers, which greatly suppresses the recombination of photogenerated carriers. As a result, the porous ZnIn₂S₄ with confined sulfur vacancies exhibits an optimum hydrogen evolution rate of up to 1537.65 ± 118.65 μmol h⁻¹ (61 506 ± 4746 μmol g⁻¹ h⁻¹), which is approximately 6 times higher than that of pristine ZIS, and achieves an apparent quantum efficiency of 56.53% at 420 ± 15 nm. This work highlights the synergistic effects of pore structure and vacancy structure for enhancing H₂ evolution performance, and further provides new ideas to design and synthesize novel photocatalysts for highly efficient solar energy conversion.