Concurrent Photocatalytic Hydrogen Generation and Dye Degradation Using MIL-125-NH2 under Visible Light Irradiation

The impact of different transition metal-based co-catalysts toward photocatalytic water reduction when they are physically mixed with visible-light active MIL-125-NH2 is first systematically studied. All co-catalyst/MIL-125-NH2 photocatalytic systems are found to be highly stable after photocatalysis, with the NiO/MIL-125-NH2 and Ni2P/MIL-125-NH2 systems exhibiting high hydrogen (H-2) evolution rates of 1084 and 1230 mu mol h(-1) g(-1), respectively. Second, how different electron donors affect the stability and H-2 generation rate of the best Ni2P/MIL-125-NH2 system is investigated and it is found that triethylamine fulfils both requirements. Then, the electron donor is replaced with rhodamine B (RhB), a dye that is commonly used as a simulant organic pollutant, with the aim of integrating the photocatalytic H-2 generation with the degradation of RhB in a single process. This is of supreme importance as replacing the costly (and toxic) electron donors with hazardous molecules present in wastewater makes it possible to oxidize organic pollutants and produce H-2 simultaneously. This is the first study where a metal-organic framework (MOF) system is used for this dual-photocatalytic activity under visible light illumination and the proof-of-concept approach envisions a sustainable waste-water remediation process driven by the abundant solar energy, while H-2 is produced, captured, and further utilized.