Lattice-Confined Ir Clusters on Pd Nanosheets with Charge Redistribution for the Hydrogen Oxidation Reaction under Alkaline Conditions,Advanced Materials

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Lattice-Confined Ir Clusters on Pd Nanosheets with Charge Redistribution for the Hydrogen Oxidation Reaction under Alkaline Conditions
Advanced Materials ( IF 27.4 ) Pub Date : 2021-09-21 , DOI: 10.1002/adma.202105400
Baohua Zhang ₁ , Guoqiang Zhao ₁ , Bingxing Zhang ₁ , Lixue Xia ₂ , Yinzhu Jiang ₁ , Tianyi Ma ₃ , Mingxia Gao ₁ , Wenping Sun ₁ , Hongge Pan _{1,

4}

Affiliation

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.

中文翻译：

用于碱性条件下氢氧化反应的带电荷重新分布的 Pd 纳米片上的晶格限制的 Ir 簇

在碱性条件下对氢氧化反应 (HOR) 具有高活性和长期稳定性的电催化剂仍然是阴离子交换膜燃料电池 (AEMFC) 的主要挑战。本文报道了一种异质结构的 Ir@Pd 电催化剂，其具有外延限制在 Pd 纳米片（NSs）上的超小 Ir 纳米团簇（NCs），用于催化缓慢的碱性 HOR。异质界面上发生明显的电荷重新分布，实验和理论结果表明电子从 Pd 转移到 Ir，从而大大削弱了 Pd 上的氢键。更有趣的是，界面外延导致 Ir/IrO ₂的形成Janus 纳米结构，其中部分氧化的 Ir 物质远离界面进一步优化了羟基吸附行为。独特的 Ir@Pd 异质结构最终显示出氢和羟基吸附之间的最佳平衡，因此表现出令人印象深刻的 HOR 活性，在 0.1 m KOH 溶液中的交换电流密度高达 7.18 mA cm ^–2。此外，由于独特的外延界面的限制效应，Ir@Pd 电催化剂的活性降低可以忽略不计。

更新日期：2021-10-27

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