Synthesis and Electrocatalysis of ternary shape-controlled octahedral Pt alloy Nano catalysts for the Oxygen Reduction Reaction

三元形控八面体铂合金纳米催化剂的合成及电催化氧还原反应

• 批准号: 461853506
• 负责人: Professor Dr. Peter Strasser
• 金额: --
• 依托单位: Arbeitsgruppe Technische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/461853506?language=en
• 关键词: Synthesis; Electrocatalysis; ternary; shape; controlled

The electrocatalytic reduction of molecular oxygen (oxygen reduction reaction, ORR) is an electrode process of great significance for metal air batteries and hydrogen fuel cells. Even on Pt surfaces, the ORR is a sluggish interfacial reaction. New Low-Pt ORR catalyst concepts are needed with enhanced intrinsic reactivity and high stability. Pt alloy single crystal-based catalyst studies predicted PtNi bimetallic octahedrally-shaped nanocatalysts as a favorable group of nanostructured particle ORR catalysts. However, electrocatalyst research involving PtNi octahedral nanoparticles largely focused on small (5-9 nm edge length) and Pt-rich nano-octahedral catalysts, which unfolded only about a tenth of their predicted intrinsic reactivity in fuel cell membrane electrode assembles (MEAs). This project will address this challenge and will investigate new tunable synthetic strategies toward octahedral Pt alloy nanoparticles of a much wider size range than that accessible today. Following our underlying hypothesis, octahedrally shaped particles of this size range will fully unfold their theoretically predicted catalytic ORR reactivity in thick realistic electrode layers.The goal of this project is to establish previously inaccessible structure-size-reactivity relationships of multi-metallic Pt alloy octahedral nanocatalysts for the ORR. Specific objectives include the discovery of new synthetic pathways with precise and tunable control over the resulting alloy particle and facet size and overall composition. Of particular interest is the size regime above 30 nm that is predicted to show particularly high intrinsic catalytic reactivities, which will benefit the resulting oxygen electrode layer performance. The project work will cover previously described bimetallic PtNi reference catalysts, yet will focus on new synthetic procedures resulting in well-defined tri-metallic PtNi-M (M=Mo and other transition metals) octahedral nanocatalysts. Synthesis will be followed by physico-chemical and electrochemical characterizations to establish structure-function correlations. Promising ternary Pt nano-octahedra will be supported on porous carbon supports with varying pore structure enabling the controlled accommodation of the large nano octahedra both inside accessible pores and on the outside surface of the primary and secondary carbon structure. These supported octahedral catalysts will be subject to electrochemical activity testing in thin film as well as thick-film electrodes of Membrane Electrode Assemblies in single PEM fuel cells.

分子氧的电催化还原（氧还原反应，ORR）是金属空气电池和氢燃料电池中具有重要意义的电极过程。即使在Pt表面上，ORR也是缓慢的界面反应。需要具有增强的固有反应性和高稳定性的新的低Pt ORR催化剂概念。基于Pt合金单晶的催化剂研究预测PtNi八面体形状的纳米催化剂作为纳米结构颗粒ORR催化剂的有利组。然而，涉及PtNi八面体纳米颗粒的电催化剂研究主要集中在小的（5-9 nm边长）和富Pt的纳米八面体催化剂上，其在燃料电池膜电极组件（MEA）中仅展现了其预测的固有反应性的约十分之一。该项目将解决这一挑战，并将研究新的可调合成策略，使八面体Pt合金纳米颗粒的尺寸范围比今天更宽。根据我们的基本假设，这个尺寸范围的八面体形状的颗粒将完全展开其理论预测的催化ORR反应在厚的现实electrode layers.The的目标是建立以前无法访问的多金属Pt合金八面体纳米催化剂的ORR的结构-尺寸-反应性关系。具体目标包括发现新的合成途径，对所得合金颗粒和小面尺寸以及整体组成进行精确和可调的控制。特别感兴趣的是高于30 nm的尺寸范围，其被预测为显示出特别高的固有催化反应性，这将有益于所得的氧电极层性能。该项目工作将涵盖先前描述的PtNi-M参考催化剂，但将专注于新的合成程序，从而产生定义明确的三金属PtNi-M（M=Mo和其他过渡金属）八面体纳米催化剂。合成之后将进行物理化学和电化学表征，以建立结构-功能相关性。有前途的三元Pt纳米八面体将负载在具有不同孔结构的多孔碳载体上，使得能够在可进入的孔内以及在初级和次级碳结构的外表面上控制容纳大的纳米八面体。这些负载的八面体催化剂将在单PEM燃料电池中的膜电极组件的薄膜以及厚膜电极中进行电化学活性测试。