Lattice‐Confined Ir Clusters on Pd Nanosheets with Charge Redistribution for the Hydrogen Oxidation Reaction under Alkaline Conditions. Issue 43 (21st September 2021)

• Record Type: Journal Article
• Authors: Zhang, Baohua; Zhao, Guoqiang; Zhang, Bingxing; Xia, Lixue; Jiang, Yinzhu; Ma, Tianyi; Gao, Mingxia; Sun, Wenping; Pan, Hongge
• Is Part Of: Advanced materials. Volume 33:Issue 43(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-09-21
• Subjects: electrocatalysis -- epitaxial growth -- heterostructures -- hydrogen oxidation reaction -- interface chemistry; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202105400
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Electrocatalysts with high activity and long‐term stability for the hydrogen oxidation reaction (HOR) under alkaline conditions is still a major challenge for anion exchange membrane fuel cells (AEMFCs). Herein, a heterostructured Ir@Pd electrocatalyst with ultrasmall Ir nanoclusters (NCs) epitaxially confined on Pd nanosheets (NSs) for catalyzing the sluggish alkaline HOR is reported. Apparent charge redistribution occurs across the heterointerface, and both experimental and theoretical results suggest that the electrons transfer from Pd to Ir, which consequently greatly weakens the hydrogen binding on Pd. More interestingly, the interfacial epitaxy results in the formation of Ir/IrO2 Janus nanostructures, where the partially oxidized Ir species away from the interface further optimize the hydroxyl adsorption behavior. The unique Ir@Pd heterostructure eventually shows an optimal balance between hydrogen and hydroxyl adsorption, and hence exhibits impressive HOR activity with an exchange current density of up to 7.18 mA cm –2 in 0.1 m KOH solution. In addition, the Ir@Pd electrocatalyst exhibits negligible activity degradation owing to the confinement effect of the unique epitaxial interface. Abstract : A highly efficient Ir@Pd heterostructured electrocatalyst is designed for the hydrogen oxidation reaction (HOR) in alkaline media. The well‐defined heterointerface with charge redistribution possesses an optimal balance between the adsorption of Had and OHad, and substantially promotes the HOR kinetics as well as durability. The results highlight the significance of engineering multifunctional heterointerface for designing advanced alkaline HOR electrocatalysts.