Development of Iridium Clusters-Loaded Tungsten Disulfide Composite Catalyst with Poisoning Tolerance for Electrochemical Ammonia Oxidation

Abstract

The electrochemical oxidation of ammonia (AOR) is a critical reaction for energy conversion and environmental remediation applications. However, the efficiency of AOR is significantly hindered by catalyst poisoning caused by adsorbed atomic nitrogen species (N_,ad), which are generated during the reaction. In this study, a novel composite catalyst consisting of iridium clusters loaded onto tungsten disulfide (Ir/WS₂) was synthesized and applied to AOR. Morphological and structural analyses confirmed the successful loading of metallic Ir clusters with an average diameter of 1.5 nm on WS₂ nanobelts. Electrochemical measurements demonstrated that the Ir/WS₂ catalyst exhibited superior activity and durability for AOR compared to conventional Ir clusters loaded onto activated carbon. This enhancement is attributed to the stable adsorption of NHx intermediate species on WS₂, which suppresses N_,ad formation via complete dehydrogenation and facilitates the dimerization of NHx intermediates. These findings highlight the potential of WS₂-based composite materials for the development of efficient and durable AOR catalysts.