Carbon Nanofibers as Potential Catalyst Support for Fuel Cell Cathodes: A Review

Polymer electrolyte membrane fuel cells (PEMFCs) are a fast growing next-generation energy conversion technology, which hold promising interest for transportation and other applications. Nevertheless, successful commercialization of PEMFCs has been significantly retarded principally due to the high cost and poor durability of Pt/C catalysts used for anodic and cathodic reactions. Under typical fuel cell operating conditions, a traditional Pt/C catalyst is prone to degrade by various mechanisms, such as electrochemical carbon corrosion, which results in detrimental effects on the long-term performance. There have been tremendous efforts undertaken to develop durable carbon supports by introducing graphitic carbon components. In this context, carbon nanofiber supported catalysts have been investigated as highly durable supports for Pt and non-Pt nanoparticles in recent years. We anticipate it is timely to review the developments in this topic. This Review highlights the current progress on the graphitic nanofibers as a catalyst support in terms of morphology, electrocatalytic activity, various functionalization strategies, and so on, specifically focusing on the effect of nanofiber edge carbons and the advantages of surface reconstruction of nanofiber edge carbon into loops with regard to the stability of carbon support and fuel cell performance. We believe this Review stands as a guide for future researchers to figure out a rational design of oxygen reduction reaction catalysts, especially dealing with highly graphitized carbons.