(569cm) Synthesis and Characterization of Ag-Based Bimetallic Transition Metals for the Oxygen Reduction Reaction in Acidic Media

The oxygen reduction reaction (ORR) stands as a crucial process in numerous electrochemical applications, notably in proton-exchange membrane fuel cells (PEMFC) and metal-air batteries. Although precious metal catalysts like Pt have long been favored in fuel cell technology, their scarcity and high cost pose significant challenges. To address this, extensive efforts have been directed towards minimizing Pt usage by employing bimetallic electrocatalysts, where a noble metal is paired with an earth-abundant transition metal. Moreover, variations in bimetallic compositions can profoundly influence catalytic performance in ORR, owing to electronic effects and induced lattice strain. Among these approaches, silver (Ag)-based bimetallic electrocatalysts have emerged as particularly promising candidates for investigating the integration of less stable transition metals into ORR processes. Consequently, this study aims to assess the efficacy of Ag-based bimetallic electrocatalysts for ORR in acidic environments by exploring the impacts of composition and electrolyte conditions. Through a combination of wet and vacuum-based synthetic techniques and electrochemical characterization, we attempt to elucidate the synergistic interactions between Ag and the secondary transition metal, leading to enhanced ORR activity and selectivity. Additionally, stability measurements were monitored using online inductively coupled plasma – mass spectrometry, affirming Ag's role in stabilizing the dissolution of the secondary metal during ORR. In essence, Ag-based bimetallic ORR electrocatalysts present a promising avenue for stabilizing earth-abundant transition metals in acidic media, thereby reducing reliance on precious metals for fuel cell technology.