Advanced Three-Dimensional Non-Precious Metal Catalysts with Tunable Active Sites for Fuel Cells

自上个世纪诞生以来，聚合物电解质膜燃料电池（pemfc）一直被高度吹捧为最有前途的技术，以满足现代社会日益增长的能源需求，同时解决环境问题。然而，阴极铂基催化剂的高成本和较差的耐久性继续阻碍着pemfc的广泛商业化。作为pt基催化剂的理想替代品，非贵金属催化剂被提出用于氧还原反应（ORR）。经过多年的发展，基于npmc的阴极的活性和耐用性仍然远远不能为PEMFC系统提供实用的解决方案。为了显著推进NPMC研究，必须解决与活性位点相关的挑战。这些挑战包括活性位点密度低、活性位点可达性低、活性位点结构不确定、固有活性低。我们建议通过合理设计npmc来克服这些挑战。具体而言，将利用活性位点原子分散等新技术，从3d前体制备三种独特的三维NPMCs (3D-NPMCs)，它们具有可调的活性位点密度、可及性和固有活性。我们将通过详细的物理化学和电化学表征以及理论计算来优化ORR的活性和耐久性，并阐明与活性位点相关的潜在因素。有前途的3d -NPMC将被制造成独特的3d结构NPMC阴极，这将被集成和广泛研究在单细胞PEMFC中。最佳电极性能和制备参数将通过实验和数值模拟确定。通过进一步广泛的PEMFC耐久性试验和相关的测试后表征，将阐明长期运行过程中性能下降和活性位点演变的机制，并相应地开发缓解策略和诊断技术。这项新研究将推进具有可调活性位点和独特3D-NPMC电极的3D-NPMC的合理设计的技术和科学知识，影响材料科学，电化学，纳米技术和清洁能源技术。它还将降低燃料电池制造和分销公司以及相关燃料电池汽车公司的成本。最后，在这项工作中受过培训的HQP将接触到来自申请人研究小组的高素质人员以及学术界和工业界的合作者。他们将有机会获得世界一流的设备来进行他们的项目和学位课程。技术、新知识和训练有素的HQP将有利于加拿大能源领域的知识型经济，同时也会引起材料科学家和工程师、化学工程师、纳米技术专家和电化学家的兴趣。

Since their birth in the last century, polymer electrolyte membrane fuel cells (PEMFCs) have been highly touted as the most promising technology to meet the ever-increasing energy demands of modern society while addressing environmental concerns. However, the high cost and poor durability of the platinum (Pt) based catalysts at cathode continue to impede widespread commercialization of PEMFCs. As a desirable alternative to Pt-based catalysts, non-precious metal catalysts (NPMCs) towards oxygen reduction reaction (ORR) were proposed. After years of progress, the activity and durability of NPMC-based cathodes are still far from providing a practical solution for PEMFC systems. To advance NPMC research significantly, challenges related to the active sites must be addressed. These challenges include low active site density, low active site accessibility, and uncertain active site structure with low inherent activity. We propose to overcome these challenges through the rational design of NPMCs. Specifically, three series of unique three-dimensional NPMCs (3D-NPMCs), with tunable active site density, accessibility, and inherent activity, will be prepared from 3D-precursors using new techniques, such as atomic dispersion of active sites. We will optimize ORR activity and durability with detailed physiochemical and electrochemical characterizations and theoretical calculations and elucidate the underlying factors related to the active sites. Promising 3D-NPMCs will be fabricated into unique 3D-architectured NPMC cathodes, which will be integrated and investigated extensively in a single cell PEMFC. The optimal electrode properties and preparation parameters will be determined via both experiment and numerical modeling. With further extensive durability tests in PEMFC and associated post-testing characterizations, the mechanism of performance degradation and active site evolution during long-term operation will be elucidated and mitigation strategies and diagnosis techniques will be developed accordingly. This novel research will advance the technical and scientific knowledge for the rational design of 3D-NPMCs with tunable active sites and unique 3D-NPMC electrodes, influencing material science, electrochemistry, nanotechnology, and clean energy technology. It also will reduce costs for fuel cell manufacturing and distribution companies, as well as related fuel cell automobile companies. Finally, the HQP trained in this work will be exposed to top-quality personnel from the applicant's research group and collaborators in academia and industry. They will have access to world-class equipment to conduct their projects and degree programs. The technology, new knowledge, and trained HQP will benefit the Canadian knowledge-based economy in the energy sector while being of interest to material scientists and engineers, chemical engineers, nanotechnologists, and electrochemists.