Electrochemical oxygen reduction plays an important role in electrochemical devices that are related to efficient energy conversion and storage such as proton exchange membrane fuel cells, direct methanol fuel cells, metal-air batteries, etc.  The oxygen reduction reaction (ORR) at cathode has sluggish reaction kinetics and it requires catalyst with high Pt loading to achieve the performance. Platinum supported on amorphous carbon (Pt/C) is the most widely used cathode catalyst system. However, the high cost, poor durability, CO poisoning and susceptibility to methanol crossover largely restrict the widespread applications of direct methanol fuel cells (DMFCs). Several cathode catalysts show a high methanol-tolerant capability but the activity and inferior long-term stability of these catalysts under fuel-cell operation conditions are inferior to Pt-based catalysts. As a result, there is a need for designing Pt-based catalysts with lower metal loading, enhanced ORR activity, better durability and good methanol tolerance. Vertically aligned carbon nanofibers (VACNFs) can be a potential candidate for enhancing or replacing Pt/C systems. VACNFs has a unique three-dimensional structure, high mechanical strength, high electrical conductivity and good chemical stability because of the interior graphitic layers. Here we demonstrated that the VACNFs can be used as a novel 3D support for reducing the Pt loading and better utilization of catalyst. The Pt/VACNF has higher catalytic activity and enhanced durability when compared with the commercial Pt/C catalyst. The Pt/VACNF also possess higher tolerance towards oxidation of methanol in the oxygen reduction region and has a higher chance of recovery in the ORR activity after CO poisoning.<br/> <br/>

Vertically aligned carbon nanofibers with reduced Pt loading as a highly active and methanol tolerant oxygen reduction electrocatalyst

2019 Spring National Meeting

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