Bimetallic IrxPb nanowire networks with enhanced electrocatalytic activity for the oxygen evolution reaction

Abstract

Metallic nanowire networks (MNNs) have attracted increasing attention due to their high surface area and tunable compositions. Although enormous efforts have been devoted to preparing noble metal MNNs with different compositions, the composition optimization and the formation mechanism of Ir-based MNNs have not been thoroughly investigated. This work presents a facile method for synthesizing robust Ir-based bimetallic MNNs by chemical reduction. As unveiled by our characterization, the network structure is constructed by ultrafine nanowires evolved from aggregated nanoparticles. The element analysis confirms the even distribution of Pb and Ir elements. The introduction of Pb is found to be beneficial to the stable formation of Ir_xPb MNNs in the sol–gel process. By tuning the precursor ratio of Ir and Pb, the optimized Ir_xPb catalyst delivers an enhanced oxygen evolution reaction (OER) performance in acid media (307 mV at 10 mA cm⁻²), which is superior to that of the commercial IrO₂ catalyst. Besides, due to the robust structure of the Ir_xPb MNNs, excellent OER durability is observed in the accelerated durability test (ADT) (2000 cycles).