The availability of low-cost, high-efficiency oxygen evolution catalysts is pivotal to the application 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) from the typical value of 60 mV decade^-1 to 43 mV decade^-1; and the overpotential for 10 mA cm^-2 of current density from 390 mV to 340 mV in 0.1 M KOH aqueous solution. Borate doping also improves the stability of α-Ni(OH)₂ in OER. The borate-doped α-Ni(OH)₂ can even surpass the reference Ir/C precious metal catalyst in both activity and stability. These results here highlights the potential of borate doping as a promising strategy to increase the catalytic activity of base metal in water oxidation catalysts.

Figure Caption:

a). Cyclic voltammograms of OER on borate-doped α-Ni(OH)2 (denoted as B-NOH), α-Ni(OH)2 (denoted as NOH), and Ir/C

b). The volcano curve of OER overpotential as a function of the boron content of B-NOH

c). The proposed mechanism on a borate-coordinated Ni active center.