物理化学学报 >> 2021, Vol. 37 >> Issue (9): 2010072.doi: 10.3866/PKU.WHXB202010072

所属专题: 燃料电池

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提升燃料电池铂基催化剂稳定性的原理、策略与方法

梁嘉顺, 刘轩, 李箐()   

  • 收稿日期:2020-10-29 录用日期:2020-11-23 发布日期:2020-11-30
  • 通讯作者: 李箐 E-mail:qing_li@hust.edu.cn
  • 作者简介:Qing Li, Email: qing_li@hust.edu.cn. Tel.: +86-18707120529
    李箐,1983年生。2010年于北京大学获得博士学位。现为华中科技大学教授,入选海外高层次人才计划青年项目。主要从事电催化、质子交换膜燃料电池、材料化学等领域的研究
  • 基金资助:
    国家自然科学基金(21972051);华中科技大学研究生创新基金(2020yjsCXCY020)

Principles, Strategies, and Approaches for Designing Highly Durable Platinum-based Catalysts for Proton Exchange Membrane Fuel Cells

Jiashun Liang, Xuan Liu, Qing Li()   

  • Received:2020-10-29 Accepted:2020-11-23 Published:2020-11-30
  • Contact: Qing Li E-mail:qing_li@hust.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21972051);the Graduates' Innovation Fund, Huazhong University of Science and Technology, China(2020yjsCXCY020)

摘要:

质子交换膜燃料电池(PEMFC)具有高转化效率、高功率密度以及低污染等优点,目前受到广泛关注。燃料电池的性能主要受限于阴极的氧还原反应,其成本也受限于阴极催化剂。目前人们已经设计了许多策略、开发了许多催化剂,特别是铂基合金催化剂,来加快氧还原反应的速率,提高燃料电池性能。然而,由于过渡金属的溶解以及纳米粒子的团聚等问题,氧还原催化剂以及燃料电池的长效稳定性仍然存在问题。如何设计高效、高稳定的燃料电池阴极催化剂,对于进一步推动燃料电池的应用十分关键。针对燃料电池阴极催化剂稳定性的问题,本文综述了近年来提升燃料电池铂基催化剂稳定性的原理、策略与方法,首先我们从热力学和动力学上阐述影响催化剂稳定性的原因及其调控原理。随后,我们将概述一些具有代表性的提升催化剂稳定性的策略和方法。最后,我们对未来发展方向进行了总结与展望。

关键词: 质子交换膜燃料电池, 电催化, 氧还原反应, 铂基催化剂, 稳定性

Abstract:

Proton exchange membrane fuel cells (PEMFCs) have attracted significant attention owing to their high conversion efficiency, high power density, and low pollution. Their performance is mainly governed by the oxygen reduction reaction (ORR) occurring at the cathode. Owing to the sluggish kinetics of ORR, a large amount of electrocatalysts, i.e., platinum (Pt), is required to accelerate the reaction rate and improve the performance of PEMFCs for practical applications. The use of Pt electrocatalysts inevitably increases the cost, thereby hindering the commercialization of PEMFCs. In addition, the activity and stability of the commercial Pt/C catalyst are still insufficient. Therefore, advanced electrocatalysts with high activity, good stability, and low cost are urgently needed. To date, some theoretical models, especially d-band center theory, have been proposed and guided the search for next-generation electrocatalysts with higher ORR activity. Based on these theories, several strategies and catalysts, especially Pt-based alloy catalysts, have been developed to accelerate ORR and improve the fuel cell performance. For instance, Pt–Ni octahedral nanoparticles (NPs) electrocatalysts have achieved remarkable ORR activity, with one order of magnitude higher activity than that of commercial Pt/C. However, PEMFCs are usually operated at a high voltage (0.6–0.8 V) and an acidic electrolyte, where the transition metals (M) are easily oxidized and etched away. The electronic effect induced by the introduction of M would be eliminated due to the dissolution of transition metals and the agglomeration of NPs, leading to the decay of ORR activity. Therefore, the long-term stability of oxygen reduction catalysts and fuel cells remains highly challenging. It is crucial to design an efficient and highly stable ORR catalyst to promote the application of PEMFCs. Aiming to the stability issues of fuel cell cathode catalysts, the current review summarizes the principles, strategies, and approaches for improving the stability of Pt-based catalysts. First, we introduce thermodynamic and kinetic principles that affect the stability of catalysts. Thermodynamic (such as cohesive energy, alloy formation energy, and segregation energy) and kinetic parameters (such as vacancy formation and diffusion barrier) regarding the structural stability of catalysts significantly affect the metal dissolution and atomic diffusion processes. In addition, these parameters seem to be associated with chemical bond energy to some extent, which could be employed as a descriptor for the stability of catalysts. Later, we outline some representative strategies and methods for improving catalyst stability, namely elemental doping, atomic arrangement engineering, chemical or physical confinement, and supporting material design. Finally, a brief summary and future research perspectives are provided.

Key words: Proton exchange membrane fuel cell, Electrocatalysis, Oxygen reduction reaction, Pt-based electrocatalyst, Stability

MSC2000: 

  • O643