Modulation of iridium-based catalyst by a trace of transition metals for hydrogen oxidation/evolution reaction in alkaline

摘要

We report that trace level of metal impurities on the surface of Ir alloy nanocrystals show a great impact on the electrocatalytic activity for the hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER). The HOR/HER activities were found to be predominantly related to OH adsorption that is related to the surface impurity content. Further, it was found that the foreign metal species on Ir surface could effectively enhance or depress HOR activity depending on their oxophilicity. We found that there is a volcano-shaped dependence of HOR/HER activity on the OH adsorption strength; and trace Fe species or moderate oxophilic Ru atoms on the surface of Ir based catalyst bring the modest OH adsorption and lead to enhanced HOR/HER activity. (C) 2019 Elsevier Ltd. All rights reserved.