Modulation of iridium-based catalyst by a trace of transition metals for hydrogen oxidation/evolution reaction in alkaline. (10th February 2020)

• Record Type: Journal Article
• Authors: Jiang, Jinxia; Liao, Jianhua; Tao, Sicheng; Najam, Tayyaba; Ding, Wei; Wang, Haijiang; Wei, Zidong
• Is Part Of: Electrochimica acta. Volume 333(2020)
• Publication Date: 2020-02-10
• Subjects: Surface modification -- HOR/HER -- Alloy and de-alloy -- OH adsorption; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.135444
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: 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. Graphical abstract: A volcano-shaped relationship between the OH adsorption strength and the catalytic activity for hydrogen oxidation was revealed by trace metal modification on the catalyst's surface, aiding future catalyst design for hydrogen oxidation/evolution reactions. Image 1 Highlights: The HOR/HER activity of Ir alloy nanocrystals can be efficiently regulated by surface-located trace metal impurities. The regulation depends on the oxophilicity of foreign metal species that change the OH adsorption strength. A volcano-shaped relationship is illustrated between the OH adsorption strength and the catalytic activity for HOR/HER.