Nickel-Iron Bimetal as a Cost-Effective Cocatalyst for Light-Driven Hydrogen Release from Methanol and Water

Light-drivenhydrogen evolution from liquid hydrogencarriers offersan innovative solution for the realization of safe storage and transportationof hydrogen. The exploration of efficient and cost-effective cocatalystsis highly desirable for constructing an affordable light-driven catalyticarchitecture. In this work, nickel-iron bimetal (NiFe) is rationallydesigned and then supported by gallium nitride nanowires (GaN NWs)/Sifor light-driven hydrogen generation from methanol aqueous solution.Under optimized conditions, the H-2 evolution rate of NiFeis even comparable to noble metals, e.g., Pt, Ru. By correlative operando spectroscopy characterizations, with density functionaltheory calculations, it is discovered that Fe is cooperative withNi for dramatically lowering the energy barrier of the potential-limitingstep of *CHO & RARR; *CO. What is more, by coordination of photoexcitedcharge carriers with photothermal effect, the production of hydrogenfrom CH3OH/H2O is evidently improved via theevolving track of *CH3O > *CH2O/*CHO >*CO >*CO2, in concurrent H2O dissociation toward (OH)-O-& BULL;. Combined with the superior optical and electronicattributes of the GaN NWs/Si semiconductor platform, NiFe bimetalenables the achievement of a marked hydrogen activity of 61.2 mmolg(-1) h(-1) by the only input of lightunder ambient conditions. This study presents a promising strategyfor hydrogen release from liquid hydrogen carriers by using earth-abundantmaterials under mild conditions.