The practical application of hexagonal ZnIn2S4 (ZIS) as a visible-light photocatalyst for hydrogen (H2) production is hindered by rapid internal charge recombination. In this study, we successfully synthesized Cu2CoSnS4 (CCTS) nanocrystals and loaded them onto the surface of ZIS nanosheets to create a p-n heterojunction photocatalyst. The optimized Cu2CoSnS4/ZnIn2S4 (CCTS/ZIS) heterojunction exhibited a significantly higher visible-light photocatalytic H2 evolution rate of 4.90 mmol·g–1·h–1 compared to ZIS and CCTS alone. The enhanced photocatalytic efficiency was attributed to improved electron transfer and charge separation at the heterojunction interface. The formation of p-n heterojunction facilitated the accumulation of valence band electrons in ZIS and conduction band holes in CCTS, effectively suppressing the recombination of photogenerated electrons and holes. Theoretical calculations as well as spectroscopic and photoelectrochemical characterizations supported the findings. This work presents a promising approach for designing efficient p-n heterojunction semiconductor photocatalysts for practical applications in visible-light-driven hydrogen evolution.

中文翻译：

---

Cu2CoSnS4/ZnIn2S4 异质结中的界面电荷分离促进光催化产氢

六方晶系 ZnIn2S4 (ZIS) 作为可见光光催化剂用于制氢 (H2) 的实际应用受到快速内部电荷复合的阻碍。在这项研究中，我们成功合成了 Cu2CoSnS4 (CCTS) 纳米晶体并将其负载到 ZIS 纳米片的表面上以创建 pn 异质结光催化剂。与单独的 ZIS 和 CCTS 相比，优化的 Cu2CoSnS4/ZnIn2S4 (CCTS/ZIS) 异质结表现出显着更高的可见光光催化析氢速率，为 4.90 mmol·g–1·h–1。光催化效率的提高归因于异质结界面处电子转移和电荷分离的改善。pn异质结的形成促进了ZIS中价带电子和CCTS中导带空穴的积累，有效抑制了光生电子和空穴的复合。理论计算以及光谱和光电化学表征支持了这些发现。这项工作提出了一种设计高效 pn 异质结半导体光催化剂的有前途的方法，可用于可见光驱动的析氢的实际应用。