Boron-incorporated IrO 2-Ta 2 O 5 coating as an efficient electrocatalyst for acidic oxygen evolution reaction

The Ir-based electrocatalysts for the acidic oxygen evolution reaction (OER) have demonstrated remarkable durability. Enhancing the Ir-based electrocatalytic activity still remains crucial owing to the scarcity of iridium. Here, a high -temperature sintering technique is employed to fabricate a boron (B) -incorporated IrO 2 -Ta 2 O 5 coating with an almost perfect rutile-type crystal structure on a corrosion -resistant titanium substrate, ensuring exceptional stability for the acidic OER. The B -incorporated IrO 2 -Ta 2 O 5 electrode fabricated in a mixed solution of 0.6 M H 3 BO 3 , exhibits an overpotential of 210 mV at a current density of 10 mA cm -2 and a lower Tafel slope of 34.2 mV dec - 1 in a 0.5 M H 2 SO 4 solution, which is far lower than the 272 mV overpotential and the 45.3 mV dec - 1 of the IrO 2 -Ta 2 O 5 /Ti electrode. The electrode possesses a minimal potential increase even after undergoing continuous OER for 400 h at a high current density of 100 mA cm -2 in a 0.5 M H 2 SO 4 solution. The incorporation of B species into IrO 2 -Ta 2 O 5 effectively fine-tunes the electronic structure of Ir active sites, leading to a substantial enhancement of the intrinsic electrocatalytic activity. This study provides promising prospects for reducing the energy consumption of noble IrO 2 -based electrocatalysts in the practical application of electrochemical industry for the acidic OER.