Self-assembled flower-like ZnIn2S4 coupled with g-C3N4@ZIF-67 heterojunction for improved photocatalytic hydrogen performance

Abstract

Enhancing the photocatalytic performance of ZnIn2S4 (ZIS) photocatalysts is a formidable task due to their structural and compositional challenges. In this investigation, a flower-like ZnIn2S4 was synthesized, coupled with a g-C3N4@ZIF-67 heterojunction, using a hydrothermal approach. Incorporating carbon-based composites led to a special electron trapping effect, effectively mitigating the photocatalytic limitations arising from the broader band gap, weak conductivity, and poor photocatalytic response activity of GCN. Consequently, introducing carbon-based composites facilitated the construction of a stable photocatalytic heterojunction. The formed heterojunction was characterized using XRD, FE-SEM, FE-TEM, EDS, XPS, electrochemical and Mott-Schottky measurements. The composite heterojunction photocatalyst, showcasing a bifunctional design, exhibited outstanding hydrogen production performance, reaching approximately 5964 μmol g−1h−1, along with remarkable stability, outperforming pure ZIS samples. Establishing a built-in electric field at the GCN-ZIS and ZIS semiconductor interface enabled the efficient separation of photogenerated charges. This design preserved the exceptional redox capability of the semiconductors. Further, it boosted the hydrogen production efficiency of the constructed bifunctional ZIS-GCN-ZIF heterojunction, presenting a promising strategy for advancing heterojunctions in hydrogen energy applications.