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

聚合物电解质膜燃料电池自上个世纪诞生以来，一直被誉为在满足现代社会日益增长的能源需求的同时解决环境问题的最有前途的技术。然而，铂(铂)基阴极催化剂的高成本和较差的耐用性仍然阻碍着质子交换膜燃料电池的广泛商业化。作为铂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，NPMC基阴极的活性和耐久性仍然远远没有为PEMFC系统提供实用的解决方案。要显著推进NPMC的研究，必须解决与活性中心相关的挑战。这些挑战包括活动站点密度低、活动站点可访问性低以及固有活动低的活动站点结构不确定。我们建议通过NPMC的合理设计来克服这些挑战。具体地说，三个系列独特的三维NPMC(3D-NPMC)，具有可调节的活性中心密度、可获得性和固有活性，将利用新的技术，如活性中心的原子分散，从3D-前体制备。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，并阐明与活性部位相关的潜在因素。有希望的3D-NPMC将被制造成独特的3D结构的NPMC阴极，并将被集成到单个电池中进行广泛的研究。通过实验和数值模拟确定最佳的电极性能和制备参数。随着PEMFC更广泛的耐久性测试和相关的测试后表征，将阐明长期运行过程中性能退化和活性中心演变的机理，并将相应开发缓解策略和诊断技术。*这一新颖的研究将为合理设计具有可调活性中心和独特3D-NPMC电极的3D-NPMC提供技术和科学知识，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，在这项工作中培训的HQP将接触到来自申请者研究小组的顶尖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级的设备来开展他们的项目和学位课程。技术、新知识和训练有素的HQP将使加拿大能源部门的知识型经济受益，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.