The individual role of pyrrolic, pyridinic and graphitic nitrogen in the growth kinetics of Pd NPs on N-rGO followed by a comprehensive study on ORR

In order to develop and replace the expensive PtC catalyst from the fuel cells, we have attempted to synthesize an efficient catalyst for oxygen reduction reaction (ORR) in an alkaline media. The materials were initially fabricated as follows; (a) synthesizing a nitrogen doped (para-xylylenediamine, nitrogen precursor) graphene oxide (N-rGO); (b) synthesizing palladium nanoparticles on graphene oxide surface (rGO-Pd). The electrochemical analysis showed that the ORR path on the N-rGO catalyst is observed to follow 2-electron mechanism. Conversely, the onset potential, current density and surface area of the rGO-Pd doesn't match with the commercially available PtC catalyst. To overcome these flaws, we have combined the individual effects of each component and fabricated N-rGO-Pd nano composite. The covalent interaction between nitrogen part of para-xylylenediamine with oxygenated functionalities of GO, followed by a strong pi-pi stacking interaction between the aromatic ring of para-xylylenediamine and GO altered the electronic distribution of the carbon support, induced more defects, influenced the size and averted the self agglomeration of the Pd NPs which lead to the astonishing catalytic activity of N-rGO-Pd catalyst. Furthermore, various spectroscopic techniques revealed the individual influence of pyrrolic, pyridinic and graphitic N on the synthesis, size and extraordinary distribution of Pd NPs. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.