Fabrication of Ni and Cd co-doped Zn ZIF-L photocatalyst for enhanced solar hydrogen evolution

Recently, photocatalytic H₂ production has gained significant attention for its potential to generate clean and renewable energy. In this study, the enhancement of H₂ production was examined by introducing various transition metal elements in Zn/Ni/Cd zeolitic imidazole frameworks photocatalysts (ZIF). The photocatalysts were synthesized using a precipitation method in water, resulting in the formation of ZIF-L structures. Increasing the Ni content leads to large particle sizes and typically reduced surface areas, owing to the increased possibility of coordination at the six coordination sites of Ni atoms. The trimetallic Zn/Ni/Cd ZIF at its optimum composition exhibits the highest absorbance and narrowest band gap, consequently yielding the highest average H₂ production rate. To address unstable reproducibility from restricted electron transfer in the optimal sample, CdS is added to form a heterojunction and to achieve stable reproducibility. Consequently, improved H₂ production is achieved by incorporating imidazole organic ligands into the co-doped trimetallic ZIF-L photocatalyst. Overall, in this study, the synthesis and optimization of ZIF composite photocatalysts are elucidated, providing insights into the design of efficient materials for sustainable energy production.