Structural Effectiveness of AgCl-decorated Ag Nanowires Enhancing Oxygen Reduction

Abstract

In anion exchange membrane fuel cells (AEMFCs) for green energy, silver (Ag)-based compounds are promising non-Pt electrocatalysts with high catalytic activity and a low cost for the oxygen reduction reaction (ORR). Although silver chloride (AgCl) shows high catalytic activity due to the ligand effect originating from the electronegativity difference between the two elements, its low electroconductivity remains a significant issue. Here, we report Ag-AgCl core–shell nanowires decorated with AgCl (AgCl-Ag@AgCl NWs) that have a structure capable of simultaneously exhibiting the good conductivity of a long silver (Ag) core and the high ORR catalytic activity of silver chloride (AgCl). In addition, by decorating AgCl nanoclusters on the AgCl shell, AgCl-Ag@AgCl NWs have an enlarged active surface. As a result, AgCl-Ag@AgCl NWs show highly improved catalytic performance (half-wave potential = 0.78 V vs a reversible hydrogen electrode (RHE), limiting current density = 4.51 mA/cm2). Accelerated durability tests (ADTs) confirm the high stability of AgCl-Ag@AgCl NWs after 4000 cycles of potential sweep and rotating ring disk electrode (RRDE) analysis shows remarkable efficiency with the high electron transfer number (n) (3.97). We also use density functional theory (DFT) calculation to confirm charge transfer, which improves the activity of our catalysts.