Enhancement Effect of Borate Doping on the Oxygen Evolution Activity of α-Nickel Hydroxide

The availability of low-cost oxygen evolution catalysts is critical to the successful commercialization of renewable energy conversion and storage systems based on solar energy and water splitting reactions. We demonstrate here that a moderate amount (∼12 wt %) of borate doping of crystalline α-Ni(OH) 2, a common low-cost catalyst, can lower the Tafel slope of the oxygen evolution reaction (OER) in 0.1 M KOH aqueous solution from the typical value of 60 to 43 mV decade –1 and the overpotential for 10 mA cm –2 of current density from 390 to 340 mV. Borate doping also improves the stability of α-Ni(OH) 2 in OER. The borate-doped α-Ni(OH) 2 can even surpass the benchmark Ir/C precious metal catalyst in terms of activity and stability. These results demonstrate the potential of borate doping as a strategy to increase the catalytic activity of base metal water oxidation catalysts.