Bimetallic Composition-Promoted Electrocatalytic Hydrodechlorination Reaction on Silver–Palladium Alloy Nanoparticles

Abstract

Studies of the electrocatalytic hydrodechlorination (EHDC) reaction using monodisperse AgPd nanoparticle (NP) model catalysts in the present work reveal the essential role of the catalytically inert Ag component in promoting bimetallic nanocatalyst’s activity for the conversion of 2,4-dichlorophenol (2,4-DCP) to phenol (P). The EHDC reaction rate, current efficiency, and product selectivity were systematically investigated, leading to the observation of a volcano-type activity dependence on the Ag content in bimetallic NPs. The combination of kinetics analyses and density functional theory calculations demonstrates that the balance of 2,4-DCP adsorption and P desorption is the dominant factor for EHDC efficiency rather than other processes (e.g., hydrogen adsorbent formation). The presence of Ag, if precisely controlled in the proper range, alleviates the overstrong adsorption of P, allowing for a much enhanced EHDC kinetics compared to single-component Pd. This work provides a deep understanding of the EHDC mechanism over bimetallic nanocatalysts and a facile approach to optimizing this important environmental electrocatalysis strategy.