The Impact of Loading and Temperature on the Oxygen Reduction Reaction at Nitrogen-doped Carbon Nanotubes in Alkaline Medium

• NCNT loading effect on ORR in alkaline medium.
• Temperature effect on ORR at NCNT.
• non-linear correlation between temperature and kinetic rate.

Metal-free nitrogen-doped carbon nanotube (NCNT) catalysts were synthesised via chemical vapour deposition with ethylenediamine and iron phthalocyanine. The electrochemically active NCNT was studied via thin-film rotating-ring disk voltamogram analysis to elucidate the optimum loading of catalysts for oxygen reduction reaction (ORR) in 0.1 M KOH electrolyte. In this study, the activity and stability of NCNT at elevated temperature were investigated. The current limiting plateau was achieved with loading above 500 μg/cm2 on glassy carbon tip with insignificant change in onset potential (c.a. +0.9 V vs RHE). The highest electron transfer number of 3.90 was obtained and it was found comparable to n = 3.95 on 130 μg/cm2 Pt/C catalysts. The subjection to cell's temperature from 298 K to 343 K showed improved activity and was found stable above 323 K.