非贵金属氧还原电催化剂设计、制备及结构与性能研究

Fuel cells have become a research focus as a clean and efficient power source in 21st century. The oxygen reduction reaction (ORR) is an important reaction in the fuel cells and the reaction kinetics is slow. Needing of noble metals such as Pt-based catalysts greatly limits the large-scale application of fuel cells. Development of highly efficient non-noble metal catalyst for ORR is the goal of this project. The transition metal and nitrogen co-doped carbon materials are selected as the research object. We develop a simple and practical synthetic route, based on the reasonably designed solution phase reactions, to effectively control the morphology, size and composition of the catalyst. The non-precious nanocatalysts with high surface areas and stable structure will be obtained. The structure and formation mechanism of the active sites of the catalysts will be explored. The effects of the structure and the proportion of active sites, pyrolysis temperature and the composition of the catalyst on the catalytic performance will be systematically investigated. By using density functional theory (DFT) calculations, the change trend map of the reaction free energy in the process of catalytic oxygen reduction will be plotted to unravel the catalytic mechanism. The relationship between the structure and performance of the catalysts is theoretically explained, further guiding our experiments to gain the optimized catalysts with high-efficiency, low-cost and good stability. Combination of theoretical prediction with experimental data provides improved synthetic strategies for the fabrication of non-noble metal oxygen reduction catalysts.

燃料电池作为21世纪清洁、高效的动力源之一，已成为当前国际上研究热点。氧还原反应是燃料电池中的重要反应，由于反应动力学缓慢，需要使用贵金属如铂作为催化剂，提高了燃料电池的成本，严重制约了燃料电池的广泛应用。本项目以发展制备高效低成本、稳定的非贵金属氧还原催化剂化目标，选取过渡金属负载的氮掺杂碳材料为研究对象。发展简单实用易操作的合成路径，以液相反应为基础，合理选择合成途径，实现对催化剂的组成及纳米结构的可控制备。有效调控催化剂的活性位点、形貌、尺寸和组成，获得多孔、高比表面积、结构稳定的催化剂。揭示催化剂活性位点结构及形成机理，研究活性中心类型、活性位点比例、热解温度、组成等对性能影响。通过密度泛函理论计算，绘制在氧还原过程中反应自由能变化趋势图，理论上阐明结构与性能之间的关系，优化实验条件，获得高效、稳定的催化剂。总结规律，为非贵金属氧还原催化剂的设计、制备和应用提供理论依据和实验方法。

燃料电池作为21世纪清洁、高效的动力源之一，已成为当前国际上研究的热点。氧还原反应是燃料电池中的重要反应，由于反应动力学缓慢，需要使用贵金属如铂作为催化剂，提高了燃料电池的使用成本，严重制约了燃料电池的广泛应用。本项目以发展制备高效低成本、稳定的非贵金属氧还原催化剂化目标，选取过渡金属负载的氮掺杂碳材料为研究对象。发展简单实用易操作的合成路径，以液相反应为基础，合理选择合成途径，实现对催化剂的组成及纳米结构的可控制备。有效调控催化剂的活性位点、形貌、尺寸和组成，获得多孔、高比表面积、结构稳定的氧还原催化材料。揭示催化剂活性位点结构的存在形式及形成机理，研究活性中心类型、活性位点比例、热解温度、组成等对电催化性能影响。通过密度泛函理论计算，绘制在催化氧还原过程中反应自由能变化趋势图，理论上阐明催化剂结构与性能之间的关系，优化实验条件，获得高效、低成本、稳定的催化剂。总结相关规律，为非贵金属氧还原催化剂的设计、制备和应用提供理论依据和实验方法。