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

该联合项目研究了高温聚合物电解质膜(HT-PEM)燃料电池电极/电解液界面的基本活化和降解机理。它结合了三个小组在材料合成、操纵态表征和电化学研究方面的丰富专业知识，促进了对操作条件下磷氧酸与铂电极表面之间潜在化学反应机理的详细理解。为此，德国PIS在硬X射线光谱学和软X射线光谱学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并加以扩展。AG Roth运用其在操纵面分析方面的专业技术，利用铂L2、3边缘的硬X射线吸收精细结构(XAFS)分析，专门探索铂和铂合金纳米颗粒催化剂在操作条件下的几何结构和电子结构是如何变化的。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，通过近边X射线吸收精细结构(NEXAFS)探测磷K边，专门解决铂电极表面与电解液(即磷酸和其他与高温质子交换膜燃料电池操作相关的磷物种)之间相互作用的变化。AG Bouzek将利用从这些复杂的表征技术中获得的见解，提出新的材料和优化的操作参数，以减少具有磷酸吸附质子交换膜的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(MicroCHP)，作为基于可再生能源的分布式能源供应中的一种高效和环境中立的组件。

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.