Micro-doping tin-bismuth on modification of Co₃O₄ electrocatalyst and degradation of ammonia nitrogen

Co₃O₄ has exhibited chlorine evolution reaction (CER) activity comparable to that of RuO₂. However, it is plagued by relatively low catalytic activity and insufficient long-term stability. In the field of cobalt oxide doping, typically, a relatively large quantity of dopants is used to modulate its performance. In contrast, the exploration of doping with trace amounts of elements has been scarce. In this study, small amounts of Sn and Bi were introduced into the Co₃O₄ electrocatalyst. The impacts of different doping ratios on the morphology and catalytic performance of the catalyst were systematically investigated. Under specific proportion conditions, the co-doping of these two elements with cobalt tetroxide demonstrated a remarkable synergistic effect. Moreover, a mechanism for the improvement of catalyst performance, based on DFT calculations, was proposed. Subsequently, the ammonia-nitrogen degradation capacity and long-term stability of the modified catalyst were evaluated through ammonia-nitrogen degradation experiments. The degradation mechanism was further elucidated using free-radical scavenging experiments.