Intermetallic Ni₂Ta Electrocatalyst for the Oxygen Evolution Reaction in Highly Acidic Electrolytes

The identification of materials capable of catalyzing the oxygen evolution reaction (OER) in highly acidic electrolytes is a critical bottleneck in the development of many water-splitting technologies. Bulk-scale solid-state compounds can be readily produced using high-temperature reactions and therefore used to expand the scope of earth-abundant OER catalysts capable of operating under strongly acidic conditions. Here, we show that high temperature arc melting and powder metallurgy reactions can be used to synthesize electrodes consisting of intermetallic Ni₂Ta that can catalyze the OER in 0.50 M H₂SO₄. Arc melted Ni₂Ta electrodes evolve oxygen at a current density of 10 mA/cm² for >66 h with corrosion rates 2 orders of magnitude lower than that of pure Ni. The overpotential required for pellets of polycrystalline Ni₂Ta to produce a current density of 10 mA/cm² is 570 mV. This strategy can be generalized to include other first-row transition metals, including intermetallic Fe₂Ta and Co₂Ta systems.