Utilisation of gelatin as nitrogen source for N-doped carbon nanotubes and its performance for the oxygen reduction reaction

Gelatin is utilised as a nitrogen source to synthesise nitrogen (N)-doped carbon nanotubes (CNTs). The N-doped CNT was prepared by mixing gelatin and CNT, followed by calcination at 500 degrees C and 800 degrees C under N-2 atmosphere. X-ray diffraction analysis shows that the higher gelatin weight ratio results in a decrease of the crystallisation. X-ray photoelectron spectroscopy deconvolution analysis confirms that pyridinic-N and pyrrolic-N have appeared at the surface of the samples. The higher calcination temperature affects the surface properties of N-doped CNT which tend to shift the pyrrolic-N to the pyridinic-N. Cyclic voltammetry analysis reveals that the presences of pyridinic-N and graphitic-N configuration have higher oxygen reduction reaction (ORR) activity compared to the N-pyrrolic structure.