In situ decorated Ni and Co in a CuBTC MOF for synergistic photocatalytic hydrogen generation

Abstract

In this study, a novel metal-organic framework (MOF), Co and Ni ion impregnated CuBTC, is synthesized and its photocatalytic hydrogen evolution reaction (HER) performance is investigated. The partial substitution of Cu2+ with Co2+ and Ni2+ ions in the catalyst is carried out and investigated to obtain critical insights into the underlying reaction mechanism. Morphological analysis revealed a well-defined octahedral structure for all photocatalysts. Among the synthesized materials, Co-Ni-CuBTC exhibited the highest HER rate of 23.9 mmol g−1 h−1, which is 6.6 times higher than that of pristine CuBTC. The photocatalyst characterization and its improved performance were corroborated using various physicochemical analyses including XRD, FTIR, XPS, and UV-DRS, and thermal stability assessments via TGA analysis. The Co-Ni-CuBTC composite exhibited a significant surface area and a prolonged average photoexcited charge lifetime of 1.03 nanoseconds, enhancing its photocatalytic HER efficiency. The structural stability of the Co-Ni-CuBTC photocatalyst is confirmed through post reaction SEM and XRD investigations. The photocatalytic mechanism study emphasizes the synergistic role of Co2+ and Ni2+ in the CuBTC framework with desirable photo redox properties for a superior HER. This work offers a promising strategy for uniformly incorporating multiple metal sites into organic frameworks to synergistically enhance photocatalytic performance.