目前质子交换膜燃料电池迫切需要活性高、稳定性好的非铂族金属催化剂以替代资源稀缺且成本高昂的铂基催化剂。本综述基于作者在该领域十几年的研究经验，讨论了目前研究所面临的挑战及可能的解决方案。作为最有前景的非贵金属氧还原电催化剂，过渡金属衍生的氮掺杂碳(M-N-C, M: Fe 或 Co)催化剂的研究在过去十年取得很大进展。但在酸性环境中稳定性较差，因而无法实际应用。目前催化剂的研究制备通常依靠基于大量的反复试验的Edisonian方法，无法实现革命性突破制备技术上可行的M-N-C催化剂。该领域迫切需要一种系统的实验设计和理论方法来真正的控制、理解和优化这类催化剂的原子排列。通过新的合成方法，高度有序的二维共轭聚合物和金属有机骨架、多孔有机聚合物及多孔树枝状聚合物等三维前驱体能够有效提高催化活性点的浓度，同时增强催化活性点在酸性电解质中的固有活性及稳定性。先进的电化学与物理表征对于催化活性点的研究是必不可少的，同时理论模拟与预测能够进一步为催化活性点与反应机理的研究提供原子级别的理解。总体而言，非铂族金属催化剂的进一步发展需要能够显著提高催化活性与稳定性的新概念与新材料。作为最新的合成策略，将大量金属原子级分散在稳定的碳基体中，同时强化N、C与金属之间的键合作用，这将有助于增强活性与稳定性。对于催化剂活性点结构的研究，需要将X射线吸收光谱以及球差电镜能谱等先进的电化学及物理表征与第一性原理密度泛函理论计算相结合。充分的认知活性点对最终发展非铂族金属催化剂是必不可少的。
Current challenge and perspective of PGM-free cathode catalysts for PEM fuel cells
DOI: 10.1007/s11708-017-0477-3
Gang WU
Abstract To significantly reduce the cost of proton exchange membrane fuel cells, platinum-group metal (PGM)-free cathode catalysts are highly desirable. Current M-N-C (M: Fe, Co or Mn) catalysts are considered the most promising due to their encouraging performance. The challenge thus has been their stability under acidic conditions, which has hindered their use for any practical applications. In this review, based on the author’s research experience in the field for more than 10 years, challenges and possible solutions to overcome these problems were discussed. The current Edisonian approach (i.e., trial and error) to developing PGM-free catalysts has been ineffective in achieving revolutionary breakthroughs. Novel synthesis techniques based on a more methodological approach will enable atomic control and allow us to achieve optimal electronic and geometric structures for active sites uniformly dispersed within the 3D architectures. Structural and chemical controlled precursors such as metal-organic frameworks are highly desirable for making catalysts with an increased density of active sites and strengthening local bonding structures among N, C and metals. Advanced electrochemical and physical characterization, such as electron microscopy and X-ray absorption spectroscopy should be combined with first principle density functional theory (DFT) calculations to fully elucidate the active site structures.
Keywords oxygen reduction, fuel cells, cathode, nonprecious metal catalysts, carbon nanocomposites
Cite this article: Gang WU. Current challenge and perspective of PGM-free cathode catalysts for PEM fuel cells [J]. Front. Energy, 19 June 2017. [Epub ahead of print] doi: 10.1007/s11708-017-0477-3
更多信息，详见：
http://journal.hep.com.cn/fie/EN/10.1007/s11708-017-0477-3
https://link.springer.com/article/10.1007/s11708-017-0477-3
