A salt-baking ‘recipe’ of commercial nickel-molybdenum alloy foam for oxygen evolution catalysis in water splitting

Ni-based metal foam holds promise as an electrochemical water-splitting catalyst, due to its low cost, acceptable catalytic activity and superior stability. However, its catalytic activity must be improved before it can be used as an energy-saving catalyst. Here, a traditional Chinese recipe, salt-baking, was employed to surface engineering of nickel-molybdenum alloy (NiMo) foam. During salt-baking, a thin layer of FeOOH nano-flowers was assembled on the NiMo foam surface then the resultant NiMo-Fe catalytic material was evaluated for its ability to support oxygen evolution reaction (OER) activity. The NiMo-Fe foam catalyst generated an electric current density of 100 mA cm −2 that required an overpotential of only 280 mV, thus demonstrating that its performance far exceeded that of the benchmark catalyst RuO 2 (375 mV). When employed as both the anode and cathode for use in alkaline water electrolysis, the NiMo-Fe foam generated a current density ( j ) output that was 3.5 times greater than that of NiMo. Thus, our proposed salt-baking method is a promising simple and environmentally friendly approach for surface engineering of metal foam for designing catalysts.