Nanostructured Palladium-based Alloy Catalysts for Fuel Cells

用于燃料电池的纳米结构钯基合金催化剂

• 批准号: 0651929
• 负责人: Arumugam Manthiram
• 金额: $ 30万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0651929&HistoricalAwards=false
• 关键词: Nanostructured; Palladium; based; Alloy; Catalysts

The rapid depletion of fossil fuels and growing environmental concerns have created enormous worldwide demand for alternative, clean energy technologies. Energy is the single greatest challenge facing humankind in the 21st century. Fuel cells offer tremendous promise for solving a variety of energy needs ranging from portable to automobile to stationary power, reducing our global dependence on oil and fostering future energy security, prosperity, and a cleaner environment. However, fuel cell technologies are confronted with numerous materials challenges associated with durability, performance, and cost, impeding the commercialization prospects. As evident from the 2004 National Research Council/National Academy of Engineering report and the American Physical Society report, a profound fundamental understanding of the chemical and physical processes in fuel cell materials is vital for enabling significant breakthroughs that will lead to enhanced fuel cell performance at an affordable cost. For example, the high cost and limited abundance of the currently used platinum catalysts pose serious problems for the commercialization prospects of fuel cells. This proposal addresses this critical issue by exploring new palladium-based alloy catalysts; the cost of palladium is one-fifth of the cost of platinum. Nanostructured palladium-based alloy catalysts for oxygen reduction reaction (ORR) are designed based on a guiding principle involving the pairing of a good oxygen-bond cleaving metal such as Co for first splitting the O-O bond to form adsorbed oxygen with a good oxygen-reduction metal such as Pd for efficiently reducing the adsorbed oxygen atoms to oxide ions. Potential catalyst compositions are identified by a cyclic voltammetric (CV) screening with glassy carbon microelectrodes. Multi-metallic binary and ternary alloy compositions consisting of palladium and other metals like Ti, V, Cr, Fe, Co, Ni, Cu, Mo, W, Ru, Au, and Pt are synthesized by novel low temperature approaches such as a reverse microemulsion method employing different reducing agents like sodium formate or sodium borohydride and polyol reduction methods, followed by heat treatment at moderate temperatures to achieve a high degree of alloying and homogeneity, small and uniform distribution of particle size, high catalytic activity, and good chemical stability. The alloy catalysts are characterized by a variety of physical techniques including diffraction, microscopy, spectroscopy, and electrochemical measurements (cyclic voltammetry, linear polarization, and rotating disk electrode methods). The catalytic activity is evaluated for both oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) in single cell proton exchange membrane fuel cells and direct methanol fuel cells with hydrogen and methanol fuels. Based on the results, a fundamental understanding of the catalytic mechanisms is developed.Intellectual Merit: The intellectual merit of the proposed activity is to (i) develop a basic scientific understanding of the factors that control the electrocatalytic activity of nanostructured palladium-based alloy catalysts for oxygen reduction reaction and methanol oxidation reaction in fuel cells, and (ii) utilize the knowledge to design and develop new less expensive, more efficient palladium-based catalysts for fuel cells. Palladium-based alloy catalysts designed with a guiding principle are synthesized by controlled, low temperature methods to keep the particle size small and maximize the catalytic activity, screened with cyclic voltammetry, and characterized by a variety of physical, chemical, and electrochemical techniques to establish the catalytic mechanisms involved. The proposed research activity will enhance our fundamental understanding of the structure-property-performance relationships of electrocatalysts and the commercialization prospects of fuel cell technology.Broader Impact: The proposed research provides a broader interdisciplinary training to students in a unique, nationally important area of materials for energy conversion, encompassing materials chemistry and electrochemical science and engineering. The realization of a strong scientific basis in this area can help to design and develop new materials for power sources for portable, automobile, and stationary applications, which would have a profound societal impact. The proposed activity also aims to recruit and train minority and women students and educate K-12 students and the general public about clean energy technologies and materials.

化石燃料和日益增长的环境问题的迅速耗尽，对替代性，清洁能源技术的需求产生了巨大的需求。能量是21世纪人类面临的最大挑战。燃料电池为解决从便携式到汽车再到固定电力的各种能源需求提供了巨大的希望，从而减少了我们全球对石油的依赖，并促进了未来的能源安全，繁荣和更清洁的环境。但是，燃料电池技术面临着与耐用性，性能和成本相关的许多材料挑战，从而阻碍了商业化的前景。从2004年国家研究委员会/美国国家工程学院报告和美国物理学会报告中可以明显看出，对燃料电池材料中化学和物理过程的深刻基本理解对于实现重大突破至关重要，这将以可承受的成本导致燃料电池的性能增强。例如，当前使用的铂催化剂的高成本和有限的丰度在燃料电池的商业化前景中构成了严重的问题。该提案通过探索新的钯基合金催化剂来解决这个关键问题。钯的成本是白金成本的五分之一。基于纳米结构化的钯基合金催化剂（ORR）是基于指导原理设计的，涉及涉及良好的氧键裂片金属（例如CO），例如首先将O-O键拆分，以形成充满氧气的氧气，并用良好的氧气金属（如Pd），例如有效地重新添加氧气，以便有效地重新添加氧气。潜在的催化剂组合物是通过用玻璃碳微电极的环状伏安法（CV）筛选来鉴定的。 Multi-metallic binary and ternary alloy compositions consisting of palladium and other metals like Ti, V, Cr, Fe, Co, Ni, Cu, Mo, W, Ru, Au, and Pt are synthesized by novel low temperature approaches such as a reverse microemulsion method employing different reducing agents like sodium formate or sodium borohydride and polyol reduction methods, followed by heat treatment at适度的温度以达到高度的合金和均匀性，粒径的小而均匀的分布，高催化活性以及良好的化学稳定性。合金催化剂的特征是多种物理技术，包括衍射，显微镜，光谱和电化学测量（环状伏安法，线性极化和旋转盘电极方法）。评估了单细胞质子交换膜燃料电池中的氧还原反应（ORR）和甲醇氧化反应（MOR）的催化活性，并用氢和甲醇燃料将甲醇燃料电池直接引导。 Based on the results, a fundamental understanding of the catalytic mechanisms is developed.Intellectual Merit: The intellectual merit of the proposed activity is to (i) develop a basic scientific understanding of the factors that control the electrocatalytic activity of nanostructured palladium-based alloy catalysts for oxygen reduction reaction and methanol oxidation reaction in fuel cells, and (ii) utilize the knowledge to design and develop new less expensive, more efficient用于燃料电池的基于钯的催化剂。钯基原理设计的基于钯的合金催化剂是由受控的低温方法合成的，以保持粒径很小并最大化催化活性，并以环状伏安法进行筛选，并以各种物理，化学，化学，化学和电化学技术的特征来建立涉及催化机制。拟议的研究活动将增强我们对电催化剂的结构质能性能关系和燃料电池技术的商业化前景的基本理解。Broader的影响：拟议的研究为学生提供了更广泛的跨学科培训。在这一领域实现强大的科学基础可以帮助设计和开发用于便携式，汽车和固定应用的电源的新材料，这将产生深远的社会影响。拟议的活动还旨在招募和培训少数民族和女学生，并教育K-12学生和公众关于清洁能源技术和材料的知识。