Nanoporous\nIridium-Based Alloy Nanowires as Highly Efficient Electrocatalysts\nToward Acidic Oxygen Evolution Reaction

Abstract

Acidic proton exchange\nmembrane water electrolysis is a prospective energy conversion technology\nfor future hydrogen production. However, its wide application is limited\nby the excessive dependence of oxygen evolution reaction on precious\nmetals at anode. To address this issue, herein, we report a class\nof IrM (M = Ni, Co, Fe) catalysts with diluted Ir content fabricated\nvia a eutectic-directed self-templating strategy. Manipulated by the\neutectic reaction and dealloying inheritance effect, the IrM catalysts\nshow a unique network structure composed of intertwining nanoporous\nnanowires. The catalytic activities of IrM nanowires show a transition-metal-dependent\nfeature, among which IrNi delivers the best activity with an exceptionally\nlow overpotential to drive 10 mA cm^–2 (283 mV) and\na high mass activity at 1.53 V vs reversible hydrogen electrode (0.732\nA mg^–1). Such performance represents a major leap\nforward compared to that of commercial IrO₂ and most of\nstate-of-the-art Ir-based acidic catalysts toward oxygen evolution\nreaction. First-principles calculations indicate that the 3d transition-metal-dependent\ncatalytic activity of IrM electrocatalysts is related to ligand effect,\nwherein the negative shift of Ir d-band center after alloying can\neffectively weaken the adsorption of reaction intermediates.