Metal-free N-doped ultrafine carbon fibers from electrospun Polymers of Intrinsic Microporosity (PIM-1) based fibers for oxygen reduction reaction

摘要

Synthesis of nitrogen-doped carbon fibers (CF) has been proved to be one of the most promising oxygen reduction reaction (ORR) Catalysts which can replace the state-of-art Pt catalyst for non-noble metal-free light-weight devices. Polymer's of Intrinsic Microporosity (PIM-1) is soluble,in common organic solvents and can be tailored by functionalization owing to nitrile groups in the backbone. PIM-1 was functionalized to anode (hydrolyzed PIM-1), amine and amidoxime groups. The modified PIM-1s were electrospun into ultrafine fibers and pyrolyzed to obtain CF. The present article investigates the influence of different functional groups on the properties of,PIM-1 based CF and their nitrogen-doping. Particularly, their ORR performance has been evaluated. Interestingly, CF from hYdrolyzed PIM-1 have the highest pore volume with small pore size among the CF based on PIM-1, amine and amidoxime PIM-1. The amount of nitrogen-doping in these CF shows the trend according to the functional groups as PIM-1 > amine > amidoxime > amide. Among all these PIM-1 baed CF; CF from PIM-1 has the highest percentage of pyridinic and graphitic nitrogen, furthermore, electrocatalysis revealed that ORR processed through four-electron with the onset potential 985 mV vs. reversible hydrogen elictrode (RHE) which is comparable with the standard Pt/C catalysts.