Operando spectroscopy of phosphorus species at the Pt electrode/electrolyte interface in HT-PEM fuel cells

该联合项目致力于高温聚合物电解质膜（HT-PEM）燃料电池中电极/电解质界面的基本激活和降解机制。它结合了三个小组在材料合成，operando表征和电化学研究方面的大量专业知识，以推进对磷氧酸与铂电极表面在操作条件下潜在化学反应机制的详细了解。为此，德国pi在硬x射线和软x射线光谱方面的实验专业知识将与捷克集团著名的电化学和燃料电池经验相结合和扩展。AG Roth将其在铂L2,3-edge上使用硬x射线吸收精细结构（XAFS）分析的operando分析专业知识应用于铂以及铂合金纳米颗粒催化剂的几何和电子结构在操作条件下的变化。AG Bär将利用其软x射线专业知识，与AG Roth密切合作开发一种原位电池，该电池可以通过近边x射线吸收精细结构（NEXAFS）探测磷的k边，以专门解决Pt电极表面和电解质之间相互作用的变化，即在高温质子交换膜燃料电池运行中磷酸和其他相关的磷种类。AG Bouzek将利用这些复杂表征技术的见解，提出新的材料以及优化的操作参数，以减少磷酸吸收质子交换膜燃料电池系统中的中毒和降解现象。在未来，这可能有助于广泛引入基于HT-PEM的热电联产电厂（microCHP），作为基于可再生能源的分布式能源供应的高效和环保的组成部分。

The joint project addresses the fundamental activation and degradation mechanisms at the electrode/electrolyte interface in high temperature polymer electrolyte membrane (HT-PEM) fuel cells. It combines the substantial expertise of three groups in materials synthesis, operando characterization, and electrochemical investigation to advance the detailed understanding of the underlying chemical reaction mechanisms between phosphorus oxoacids and the platinum electrode surface under operating conditions. To do so, the experimental expertise of the German PIs in hard and soft X-ray spectroscopy will be combined and extended by the renowned electrochemistry and fuel cell experience of the Czech group. AG Roth applies its expertise in operando analysis using hard X-ray absorption fine structure (XAFS) analysis at the platinum L2,3-edge to specifically probe how the geometric and electronic structure of the platinum as well as platinum-alloy nanoparticle catalyst changes under operating conditions. AG Bär will make use of its soft X-ray expertise to develop – in close collaboration with AG Roth – an in-situ cell that allows probing of the phosphorus K-edge by near edge X-ray absorption fine structure (NEXAFS) to specifically address changes in the interaction between Pt electrode surface and electrolyte, i.e. phosphoric acid and other phosphorus species of relevance in HT-PEM fuel cell operation. AG Bouzek will utilize the insight from these sophisticated characterization techniques to suggest novel materials as well as optimized operation parameters to reduce poisoning and degradation phenomena in fuel cell systems with phosphoric acid imbibed proton-exchange membranes. In the future, this may help to widely introduce combined heat and power plants (microCHP) based on HT-PEM as a highly efficient and environmentally neutral component of the distributed energy supply based on renewable energy sources.