Yao Ze-Cheng, Tang Tang, Jiang Zhe, Wang Lu, Hu Jin-Song, Wan Li-Jun
Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100190, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Nano. 2022 Apr 26;16(4):5153-5183. doi: 10.1021/acsnano.2c00641. Epub 2022 Apr 14.
With the potential to circumvent the need for scarce and cost-prohibitive platinum-based catalysts in proton-exchange membrane fuel cells, anion-exchange membrane fuel cells (AEMFCs) are emerging as alternative technologies with zero carbon emission. Numerous noble metal-free catalysts have been developed with excellent catalytic performance for cathodic oxygen reduction reaction in AEMFCs. However, the anodic catalysts for hydrogen oxidation reaction (HOR) still rely on noble metal materials. Since the kinetics of HOR in alkaline media is 2-3 orders of magnitude lower than that in acidic media, it is a major challenge to either improve the performance of noble metal catalysts or to develop high-performance noble metal-free catalysts. Additionally, the mechanisms of alkaline HOR are not yet clear and still under debate, further hampering the design of electrocatalysts. Against this backdrop, this review starts with the prevailing theories for alkaline HOR on the basis of diverse activity descriptors, ., hydrogen binding energy theory and bifunctional theory. The design principles and recent advances of HOR catalysts employing the aforementioned theories are then summarized. Next, the strategies and recent progress in improving the antioxidation capability of HOR catalysts, a thorny issue which has not received sufficient attention, are discussed. Moreover, the significance of correlating computational models with real catalyst structure and the electrode/electrolyte interface is further emphasized. Lastly, the remaining controversies about the alkaline HOR mechanisms as well as the challenges and possible research directions in this field are presented.
由于有可能规避质子交换膜燃料电池中对稀缺且成本高昂的铂基催化剂的需求，阴离子交换膜燃料电池（AEMFC）正作为零碳排放的替代技术而兴起。人们已经开发出许多无贵金属催化剂，它们在AEMFC的阴极氧还原反应中具有优异的催化性能。然而，用于氢氧化反应（HOR）的阳极催化剂仍然依赖于贵金属材料。由于碱性介质中HOR的动力学比酸性介质中的低2 - 3个数量级，提高贵金属催化剂的性能或开发高性能的无贵金属催化剂都是一项重大挑战。此外，碱性HOR的机理尚不清楚，仍在争论中，这进一步阻碍了电催化剂的设计。在此背景下，本综述首先基于多种活性描述符，即氢结合能理论和双功能理论，介绍了关于碱性HOR的主流理论。然后总结了采用上述理论的HOR催化剂的设计原则和最新进展。接下来，讨论了提高HOR催化剂抗氧化能力的策略和最新进展，这是一个尚未得到充分关注的棘手问题。此外，进一步强调了将计算模型与实际催化剂结构以及电极/电解质界面相关联的重要性。最后，介绍了关于碱性HOR机理的剩余争议以及该领域的挑战和可能的研究方向。
