Poly(ferrocenedimethano)cyclotriphosphazene to Homogenously Fe, N, P, O Doped Carbon Nanotubes: An efficient and tremendous electrocatalyst for oxygen reduction reaction

Development of heteroatoms doped one-dimensional carbon nanotubes (1D CNTs) have grabbed great attentions for energy applications. A precise approach for the synthesis of homogenous-doped atoms 1D CNTs remains a big challenge, particularly due to foreign doping of the metal atoms. Herein, we reported homogeneous doing of metal (Fe) and non-metal (N, P, O) atoms into carbon lattice via synthesis of novel iron-containing Poly(ferrocenedimethano)cyclotriphosphazene (PFC) 1D NTs followed by their pyrolysis at various temperatures (600, 800, 1000°C). These electrocatalysts were represented as PFC-600, PFC-800 and PFC-1000, respectively and they exhibited a homogeneous distribution of Fe, N, P, O into carbon lattice. Cyclic voltammetry measurements depicted a notable cathodic peak at 0.86 V vs RHE and maximal current density 2.43 mA cm² for PFC-800 infers its substantial enhanced ORR performance compared with its counterpart electrocatalysts (PFC-600, PFC-1000) and Pt/C. The PFC-800 also showed superior stability and higher methanol tolerance compared commercial Pt/C. The higher performance was attributed to 1) a precise and homogeneous distribution of Fe atoms resulting in promotion of initial O₂ adsorption and generate more active sites; 2) highest surface area and hierarchical porous structure contribute for enhanced-flux mass transport. This design will provide a facile pathway for homogeneous doping of other metals and non-metals atoms into carbon lattice to construct a highly efficient and cost-effective ORR catalyst.