Catalytic activity of nitrogen-containing functional groups supported on carbon structures for cathodic oxygen reduction reaction for PEM fuel cells

摘要：Umit Ozkan机构：俄亥俄州州立大学提案编号：0437451研究与使用铂（Pt）催化剂相关的高成本，加上聚合物电解质膜（PEM）燃料电池中最重要的潜在损失是由于阴极中氧还原反应（ORR）的动力学，导致几项研究集中在新型ORR催化剂的开发上。 其中一些研究是基于自然启发的概念，使用血红蛋白型分子来执行氧还原功能。 据报道，含有铁（Fe）或钴（Co）中心的大有机大环在负载于高表面积碳上时对ORR具有活性。 尽管这些络合物在燃料电池环境中长时间不稳定，但当它们经受热处理时，尽管文献中有大量证据表明碳载氮官能团可能具有氧还原活性，但剩余的具有金属中心的含氮碳结构显示出活性和稳定性（含金属中心和不含金属中心）作为PEM燃料电池阴极电催化剂，其活性中心的性质和氧还原反应的机理还没有明确的认识。本研究的重点是研究含氮碳纳米结构中氧还原活性中心的性质，作为PEM燃料电池的潜在阴极催化剂。 主要目标是（a）获得对活性位点的性质、金属中心和碳载体结构的作用的基本理解，（B）开发用于这些催化剂的纳米级合成的技术和（c）建立将导致用作燃料电池电极的新型非贵金属催化材料的纳米级设计的知识库。虽然拟议研究的最终目标是开发新型无铂PEM燃料电池电极，但本研究将侧重于含氮碳电极材料的合成，以具体研究和评估影响氧还原活性的因素，金属/氮官能团/碳纳米结构/氧还原活性之间的相互关系，负责活性的活性位点，活性位点形成所需的前体材料的形式以及这些材料在真实的条件下的性能和稳定性。广泛的影响氢经济的发展是一个国家目标-因此，促进燃料电池广泛应用的技术的发展变得越来越重要。 这项工作的结果可以使燃料电池的应用更接近现实。 其他影响包括课程开发（“催化和燃料电池”新课程，OSU-IGERT计划中的系列研讨会），为研究生和本科生研究人员提供培训场所，并创建演示工具用于“女性工程新生定向”计划，该计划将捕捉想象力，并让他们对工程职业感到兴奋。 该项目还将加强P.I.法国CNRS催化研究所

ABSTRACTPI: Umit OzkanInstitution: Ohio State UniversityProposal Number: 0437451ResearchThe high costs associated with the use of platinum (Pt) catalysts coupled with the fact that the most significant potential loss in polymer electrolyte membrane (PEM) fuel cells is due to the kinetics of the oxygen reduction reaction (ORR) in the cathode have led several studies to focus on the development of novel ORR catalysts. Some of these studies are based on the nature-inspired concept of using hemoglobin-type molecules to perform the oxygen reduction function. Large organic macrocycles containing iron (Fe) or cobalt (Co) centers are reported to be active for ORR when supported on high-surface area carbon. Although these complex compounds are not stable for long periods of time in the fuel cell environment, when they are subjected to a heat treatment, the remaining nitrogen-containing carbon structures with metal centers are shown to be active and stable.Although there is ample evidence in the literature about the possible oxygen reduction activity of carbon-supported nitrogen functional groups (with and without metal centers) as potential cathode electrocatalysts for PEM fuel cells, there is no clear understanding about the nature of active sites and the mechanism of oxygen reduction reaction. The focus of this proposal is investigation of the nature of oxygen reduction active sites in nitrogen containing carbon nano-structures as potential cathode catalysts for PEM fuel cells. The main objectives are (a) acquiring a fundamental understanding of the nature of active sites, the role of the metal centers and the carbon support structure, (b) developing techniques for nano-scale synthesis of these catalysts and (c) building a knowledge base that would lead to the nano-scale design of novel, non-precious metal catalytic materials to be used as fuel cell electrodes. While the ultimate goal of the proposed research is the development of novel, platinum-free PEM fuel cell electrodes, the present study will focus on the synthesis of nitrogen-containing carbon electrode materials to specifically study and assess the factors contributing to oxygen reduction activity, the inter-relation between metal/nitrogen functional groups/carbon nano-structure/oxygen reduction activity, the active site(s) responsible for activity, the forms of precursor material necessary for active site formation, and the performance and stability of these materials under real conditions.Broad ImpactThe move to a hydrogen economy is a national target - consequently the development of technologies that facilitate wide application of fuel cells are becoming increasingly important. The results of this work could bring the application of fuel cells closer to reality. Other impacts include curriculum development (new course in "Catalysis and Fuel Cells", seminar series in OSU-IGERT program), providing a training ground for graduate and undergraduate researchers, and creating demonstration tools to be used in the "Orientation for Women Engineering Freshmen" program that would capture the imagination and that would get them excited about a career in engineering. The project will also strengthen an existing international collaboration between the P.I. and the French CNRS-Catalysis Research Institute.