Coupled DMF and H2O photocatalytic hydrogen production via ZnIn2S4@MIL-125(Ti) heterojunction

Producing hydrogen from organic/inorganic hydrides is an innovative clean energy alternative to fossil fuels , addressing the increasing energy demands. Here, we first propose coupled photocatalytic water hydrogen production and N,N-dimethylformamide (DMF, C 3 H 7 NO) dehydrogenation technology to obtain high value-added H 2 and N,N-dimethylcarbamic acid (C 3 H 7 NO 2 ). ZnIn 2 S 4 @MIL-125(Ti) nanoheterostructures were synthesized using a simple solvothermal method and resulting in a photocatalytic H 2 production rate of 2.135 mmol h −1  g −1 (apparent quantum efficiency at 380 nm was 2.6 %) which is 2.77 times higher than pure ZnIn 2 S 4 . Liquid-phase mass spectrometry indicates that the DMF oxidation activity of ZIS@MIL heterojunction is double pure ZnIn 2 S 4 and only microcrystalline CO 2 is produced. Isotopes indicate that the production pathway of H 2 results from the coupling of the –CHO bond in DMF and the –H in water. The improved photocatalytic activity of the ZnIn 2 S 4 @MIL-125(Ti) heterostructure is attributed to facilitating efficient charge carrier transfer and separation and DMF depletion of holes accelerates electron transfer .