Structure-performance relationships of Ir-Ru electrodes for oxygen evolution during dynamic operation

动态运行过程中析氧的 Ir-Ru 电极的结构-性能关系

• 批准号: 406938448
• 负责人: Dr. Serhiy Cherevko
• 金额: --
• 依托单位: Institut für Angewandte Materialien - Elektrochemische Technologien (IAM-ET)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/406938448?language=en
• 关键词: Structure; performance; relationships; Ir; Ru

This project deals with the structure-performance relationships of Ir-Ru electrodes for oxygen evolution reaction during dynamic operation of proton exchange membrane water electrolysers. Whereas electrolyzers are key enablers for efficient storage of renewables within the "Energiewende", oxygen evolution is one of the most challenging and complex reactions hindering wide-spread application of this technology. The complexity grows even larger as the intermittent nature of renewable energy requires dynamic operation. For this purpose a fundamental understanding of the processes at the catalyst during dynamic oxygen evolution is required. Whereas state-of-the-art catalysts are based on pure Ir, Ir-Ru anodes show superior performance but lower stability, including changes in oxidation state, surface/bulk structure, morphology and even dissolution. The complex interaction of catalyst structure and electrochemical activity is not understood yet, but of utmost importance for enabling high performance, durable and low cost electrolyzers. The main objective of this proposal is to gain insight into the structure-performance relationships of Ir-Ru anodes for oxygen evolution during dynamic operation. Special focus is on changes of the catalyst composition and oxidation state and their effect on reaction kinetics, and as such on catalyst activity and durability. We will elucidate, how the structure and performance changes upon full load, partial load and dynamic operation and what limits the feasible operating range. To achieve these objectives, we will develop a methodology which interlinks in situ/operando spectroscopic and spectrometric methods, which characterize catalyst state and structure, with advanced electrochemical methods and kinetic modeling techniques, which analyze and predict performance for given catalyst states. This interdisciplinary approach includes new cells for operando X-ray spectroscopy to unravel the structure during dynamic operation and on-line inductively coupled plasma mass spectrometry and electrochemical spectroscopy setups for prescreening Ir:Ru compositions and in-depth mechanistic analysis. Results from operando spectroscopy and electrochemical characterization are combined with kinetic models that describe changes in reaction kinetics and catalyst structure and their interaction as a function of (dynamic) operating conditions. Experimentally validated kinetic models give insight into the processes at the catalyst and aid in interpreting measurements. In essence, this combination of experimental and theoretical efforts allows not only for a deeper understanding of structure-performance relationships of electrocatalysts, here exemplarily for oxygen evolution, but also for prediction of performance during dynamic operation and identification of favorable operating regimes. Moreover, the gained understanding of catalyst dynamics during oxygen evolution will pave the way for new catalysts.

本计画主要研究在质子交换膜水电解槽动态操作下，Ir-Ru电极析氧反应的结构与性能关系。虽然电解槽是在“能源转型”中有效储存可再生能源的关键推动因素，但析氧是阻碍该技术广泛应用的最具挑战性和最复杂的反应之一。由于可再生能源的间歇性需要动态运行，复杂性甚至会变得更大。为此，需要对动态析氧过程中催化剂处的过程有基本的了解。尽管现有技术的催化剂基于纯Ir，但Ir-Ru阳极显示出上级性能但较低的稳定性，包括氧化态、表面/本体结构、形态甚至溶解的变化。催化剂结构和电化学活性的复杂相互作用尚未被理解，但对于实现高性能、耐用和低成本的电解槽至关重要。本提案的主要目的是深入了解Ir-Ru阳极在动态操作过程中析氧的结构-性能关系。特别关注的是催化剂组成和氧化态的变化及其对反应动力学的影响，以及对催化剂活性和耐久性的影响。我们将阐明，结构和性能如何在满载，部分负载和动态操作时变化，以及限制可行操作范围的因素。为了实现这些目标，我们将开发一种方法，该方法将表征催化剂状态和结构的原位/操作光谱和光谱方法与先进的电化学方法和动力学建模技术联系起来，分析和预测给定催化剂状态的性能。这种跨学科的方法包括新的细胞operando X射线光谱解开动态操作过程中的结构和在线电感耦合等离子体质谱和电化学光谱设置预筛选Ir：Ru组合物和深入的机理分析。操作光谱和电化学表征的结果与动力学模型相结合，该模型描述了反应动力学和催化剂结构及其相互作用的变化作为（动态）操作条件的函数。实验验证的动力学模型可以深入了解催化剂的过程，并有助于解释测量结果。本质上，这种实验和理论努力的结合不仅允许更深入地理解电催化剂的结构-性能关系，这里示例性地用于析氧，而且允许预测动态操作期间的性能和识别有利的操作状态。此外，对析氧过程中催化剂动力学的理解将为新催化剂的开发铺平道路。