Sacrificial Cu Layer Mediated the Formation of an Active and Stable Supported Iridium Oxygen Evolution Reaction Electrocatalyst,ACS Catalysis

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Sacrificial Cu Layer Mediated the Formation of an Active and Stable Supported Iridium Oxygen Evolution Reaction Electrocatalyst
ACS Catalysis ( IF 11.3 ) Pub Date : 2021-09-28 , DOI: 10.1021/acscatal.1c02968
Anja Lončar _{1,

2} , Daniel Escalera-López ₃ , Francisco Ruiz-Zepeda ₁ , Armin Hrnjić _{1,

2} , Martin Šala ₄ , Primož Jovanovič ₁ , Marjan Bele ₁ , Serhiy Cherevko ₃ , Nejc Hodnik _{1,

2}

Affiliation

The production of hydrogen via a proton-exchange membrane water electrolyzer (PEM-WE) is directly dependent on the rational design of electrocatalysts for the anodic oxygen evolution reaction (OER), which is the bottleneck of the process. Here, we present a smart design strategy for enhancing Ir utilization and stabilization. We showcase it on a catalyst, where Ir nanoparticles are efficiently anchored on a conductive support titanium oxynitride (TiON_x) dispersed over carbon-based Ketjen Black and covered by a thin layer of copper (Ir/CuTiON_x/C), which gets removed in the preconditioning step. Electrochemical OER activity, stability, and structural changes were compared to the Ir-based catalyst, where Ir nanoparticles without Cu are deposited on the same support (Ir/TiON_x/C). To study the effect of the sacrificial less-noble metal layer on the catalytic performance of the synthesized material, characterization methods, namely X-ray powder diffraction, X-ray photoemission spectroscopy, and identical location transmission electron microscopy were employed and complemented with scanning flow cell coupled to an inductively coupled plasma mass spectrometer, which allowed studying the online dissolution during the catalytic reaction. Utilization of these advanced methods revealed that the sacrificial Cu layer positively affects both Ir OER mass activity and its durability, which was assessed via S-number, a recently reported stability metric. Improved activity of Cu analogue was ascribed to the higher surface area of smaller Ir nanoparticles, which are better stabilized through a strong metal–support interaction (SMSI) effect.

中文翻译：

牺牲铜层介导了活性稳定的负载型铱析氧反应电催化剂的形成

通过质子交换膜水电解槽 (PEM-WE) 制氢直接取决于阳极析氧反应 (OER) 电催化剂的合理设计，这是该过程的瓶颈。在这里，我们提出了一种用于提高 Ir 利用率和稳定性的智能设计策略。我们在催化剂上展示了它，其中 Ir 纳米粒子有效地锚定在导电载体氧氮化钛 (TiON _x )上，该载体分散在碳基科琴黑上，并被一层薄薄的铜 (Ir/CuTiON _x /C)覆盖，铜被去除在预处理步骤中。将电化学 OER 活性、稳定性和结构变化与 Ir 基催化剂进行比较，其中不含 Cu 的 Ir 纳米颗粒沉积在相同的载体上（Ir/TiON _x/C）。为了研究牺牲性低贵金属层对合成材料催化性能的影响，采用X射线粉末衍射、X射线光电发射光谱和同位透射电子显微镜等表征方法，并辅以扫描流池耦合到电感耦合等离子体质谱仪，可以研究催化反应过程中的在线溶解。利用这些先进的方法表明，牺牲铜层对 Ir OER 质量活性及其耐久性产生积极影响，这是通过 S 数评估的，这是最近报道的稳定性指标。Cu 类似物的活性提高归因于较小的 Ir 纳米颗粒具有更高的表面积，

更新日期：2021-10-15

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