Surface-adsorbed phosphate boosts bifunctionally electrocatalytic activity of Ni0.9Fe0.1S for hydrogen production

Development of efficient and inexpensive electrocatalysts for hydrogen production via water electrolysis is of great significance. Up to date, the oxygen evolution reaction (OER) is still the efficiency limiting step for overall water splitting. Here, we report a highly efficient bifunctional electrocatalyst of 3D Ni0.9Fe0.1S:Pi nanoflower arrays for HER and OER enabled by surface-adsorbed phosphate. More importantly, the resulting electrode can also catalyze organic molecules such as ethanol and glycerin to be oxidized to value-added liquid products by replacing OER for hydrogen production. With the presence of glycerol, an electrolyzer assembled using the as-prepared electrode needed an ultralow potential of 1.49 V to drive a current density of 10 mA cm-2 for efficient hydrogen production. This work sheds light on great promise of integration of oxidative biomass valorization with HER via earth-abundant electrocatalysts for yielding value-added products with lower voltage input and maximizing the energy conversion efficiency.