Interlaced Pd–Ag nanowires rich in grain boundary defects for boosting oxygen reduction electrocatalysis

Abstract

Given the high cost and poisoning issues of Pt, developing Pd-based catalysts as substitutes is highly essential. Although substantial progress has been made, the synthesis of Pd-based electrocatalysts with both high activity and stability in the oxygen reduction reaction (ORR) remains a challenge. In this work, we prepared Pd–Ag nanowires with up to micro-sized length and a diameter of ∼17 nm via a facile modified polyol method. The obtained Pd–Ag nanowires (NWs) exhibit interlaced features and are rich in grain boundary defects. Due to the continuous grain boundaries in the one-dimensional (1D) structure and the optimized composition, the synthesized Pd₁Ag₁ NWs show half-wave potential of 0.897 V and mass activity of 0.103 A mg⁻¹ in alkaline media toward ORR, higher than those of both state-of-the-art Pt/C and other Pd–Ag counterparts. Significantly, after stability tests over 5000 cycles, Pd₁Ag₁ NWs shows a 2 mV positive shift, much better than that of Pt/C, exhibiting striking stability for ORR. This work may provide an avenue to construct advanced catalysts by surface defect engineering.