Ji, Sang Gu Kim, Minho M. Han, Man Ho Cho, Junsic Son, Yoosang Kim, Young Yong Jeong, Jaeyoung Kim, Zee Hwan Chae, Keun Hwa Oh, Hyung-Suk Kim, Hyungjun Choi, Chang Hyuck 2025-01-20T01:30:20Z 2025-01-20T01:30:20Z 2025-01-17 2024-12 2520-1158 https://pubs.kist.re.kr/handle/201004/151590 Alkali metal cations (AM+) exhibit high solubility and ionic conductivity, making them optimal components in aqueous electrolytes. Despite the conventional belief that AM+ are chemically inert spectators, the strong dependence of electrocatalysis on AM+ has recently provoked debates about their unforeseen catalytic role. However, conclusive evidence is still lacking. Here we demonstrate that AM+ can couple with reaction intermediates and determine kinetics as homogeneous cocatalysts in aqueous conditions, for the alkaline oxygen reduction reaction on a carbon catalyst. In situ X-ray absorption spectroscopy reveals a change in the electronic structure of Na+ from its hydrated state on a charged electrode. In situ Raman spectroscopy further identifies that this change is due to the formation of water-unstable NaO2 as a key intermediate in OOH- production. Together with theoretical calculations, this finding enunciates the counterintuitive cocatalytic role of AM+ in aqueous environments, highlighting the exigency of refined interface design principles for better electrocatalysis. English NATURE PUBLISHING GROUP Alkali metal cations act as homogeneous cocatalysts for the oxygen reduction reaction in aqueous electrolytes Article 10.1038/s41929-024-01241-1 1 Nature Catalysis, v.7, no.12, pp.1330 - 1338 Nature Catalysis 7 12 1330 1338 N scie scopus 001381576500012 2-s2.0-85212776402 Chemistry, Physical Chemistry Article FREE-ENERGY CARBON WATER OXIDATION CO2 ELECTROCATALYSIS MECHANISM H2O ELECTROCHEMICAL REDUCTION HYDROGEN EVOLUTION