Advances in Nanofiber-based Electrocatalysts for Oxygen Reduction Reaction

The excessive usage of fossil fuels is accompanied by the environmental pollution problems. Positively explore and develop green and sustainable energy conversion and storage technologies is of great significance to alleviate the environmental problems. Proton exchange membrane fuel cells (PEMFC) and metal air battery (MAB) stand out among many energy technologies. The oxygen reduction reaction (ORR), as critical part of PEMFC and MAB, seriously restrict the widespread use of PEMFC and MAB due to the multistep proton-electron coupling process and high energy barrier. The advantages of fiber structure, including high specific surface area, adjustable geometric structure,simple and convenient preparation, make it a new emerging architecture for the fabrication of electrocatalyst toward oxygen reduction reaction. In this review, the preparation of nanofibers and adjustable metal site in nanofiber-based electrocatalysts are summerized, and the latest progresses of nanofiber-based electrocatalyst toward ORR are discussed. Moreover, the structure-activity relationship of nanofiber-based electrocatalysts toward ORR is revealed. Finally, the challenges and opportunities of nanofiber-based electrocatalyst for ORR electro-catalysis are discussed.