Synergistic Effect of CuBDC and ZnIn₂S₄ in a Novel Heterostructure for Efficient Photocatalytic Water Splitting

Hydrogen is widely recognized as a clean and sustainable fuel, yet efficient and low-cost production methods remain a major scientific challenge. Among them, photocatalytic water splitting using sunlight is one of the most attractive approaches. In this study, we report the design and fabrication of a novel CuBDC@ZnIn₂S₄ heterostructured composite aimed at improving hydrogen evolution under visible light. Our motivation was based on the complementary strengths of both materials: CuBDC, a copper-based metal-organic framework (MOF) with high surface area and porous structure, and ZnIn₂S₄, a visible-light-responsive semiconductor known for its suitable bandgap (~۲.۴ eV) and good stability. By integrating these two components, we aimed to enhance light absorption, promote charge separation, and increase the number of active catalytic sites. The synthesis process was carefully optimized. CuBDC nanosheets were first synthesized through a solvothermal method, followed by in-situ growth of ultrathin ZnIn₂S₄ nanosheets on their surface via a mild hydrothermal step. This gentle assembly ensured good interface contact between the MOF and the semiconductor. To confirm the successful synthesis of the composite and investigate its structural and optical properties, various characterization techniques were employed. X-ray diffraction (XRD) confirmed the crystalline phases and verified the formation of the composite. Fourier-transform infrared spectroscopy (FTIR) revealed chemical interactions between the MOF and the semiconductor. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated the morphological integration and uniform distribution of components, confirming the formation of a well-defined heterojunction interface. According to BET analysis, the CuBDC@ZnIn₂S₄ composite retained a relatively high surface area despite partial pore blocking by ZnIn₂S₄. This preserved porosity, together with the inherent visible-light responsiveness and stability of ZnIn₂S₄ and the porous structure of CuBDC, promotes light absorption, efficient charge separation, and provides abundant active sites for enhanced photocatalytic hydrogen evolution. The final goal of this research is to apply the CuBDC@ZnIn₂S₄ composite in photocatalytic hydrogen production from water under visible light irradiation, aiming for sustainable and low-cost solar-to-hydrogen conversion. Preliminary results show promising activity, highlighting the potential of this composite in future clean energy applications.

کلیدواژه ها:

CuBDC@ ZnIn₂S₄ ، Water splitting ، Hydrogen ، Photocatalyst ، Visible light