Nitrogen-doped porous carbon-catalyzed oxygen reduction reactions optimized by secondary pyrolysis
Nitrogen-doped carbon-based metal-free catalysts were prepared using secondary pyrolysis.It was found that the prepared catalyst had a high half-wave potential of 0.905 V in an alkaline environment and that the half-wave poten-tial only decayed by 8 mV after 10 000 cycles of accelerated endurance testing;the zinc-air cell assembled from the cata-lyst exhibited a power density of 180 mW∙cm-2.The experimental results show that the secondary pyrolysis will form more micropores,increase the specific surface area of the material,and promote the effective exposure of the active sites.Moreover,it can promote a higher degree of graphitization of the catalyst,which slows down the carbon corrosion and avoids a large loss of doped nitrogen during the oxygen reduction process,thus improving the stability of the catalyst.
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