Hierarchically porous Mo-doped Ni-Fe oxide nanowires efficiently catalyzing oxygen/hydrogen evolution reactions

Developing cost-effective, active and robust electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in the same electrolyte still remains a crucial challenge for boosting the efficient conversion of sustainable energy resources. Here, based upon rapid solidification and the dealloying inheritance effect, a eutectic-derived self-templating strategy is reported to fabricate hierarchically porous Mo-doped Ni-Fe oxide nanowires for catalyzing overall water splitting. The advanced catalyst exhibits a remarkably low overpotential (only requires an overpotential of 231 mV for 10 mA cm −2 ) and low Tafel slope (39 mV dec −1 ) towards the OER in 1 M KOH. Comparing with the Ni-Fe oxide without Mo-doping, the Mo-doped Ni-Fe oxide nanowires show enhanced activities towards the HER with 84 mV less overpotential to drive a current density of 10 mA cm −2 . Strikingly, an alkaline electrolyzer assembled by using the Mo-doped Ni-Fe oxide nanowires as both the anode and the cathode consumes a cell voltage as low as 1.62 V (at 10 mA cm −2 ). The exceptional properties of the catalyst can be ascribed to its well-designed hierarchically porous nanowire network, and enhanced electric conductivity profiting from the remaining Ni metal in the oxide, as well as the synergistic effect of Mo and the Ni-Fe system. These favorable factors concurrently contribute to the boosted active surface area, facilitated electron/electrolyte transport, and accelerated reaction kinetics of water splitting. Hierarchically porous Mo-doped Ni-Fe oxide nanowires were synthesized via a eutectic-derived self-templating strategy, which exhibit superior electro-catalytic performance towards the OER/HER.