Highly Efficient Electrocatalysis of Metal-Free, Graphitic and Sustainable Nitrogen Doped Mesoporous Carbon Towards Oxygen Reduction Reaction

Abstract

Novel well-ordered and sustainable nitrogen doped mesoporous carbon (NMC-G) materials having the graphitic wall structure have been fabricated using a low cost gelatin, a natural biopolymer as a carbon precursor and SBA-15 as a sacrificial hard template via nano-casting method. The obtained materials were unambiguously characterized by several sophisticated techniques such as powder XRD, N-2 adsorption-desorption, electron energy loss spectroscopy (EELS), high-resolution scanning electron microscopy (HRSEM), X-ray photoelectron spectroscopy (XPS), and elementary analysis. The graphitic character and intrinsic properties of the well-ordered NMC-G materials can be controlled by the simple and fine adjustment of the carbonization temperature during the synthesis. The obtained well-ordered NMC-G materials were employed as metal free electrocatalysts in oxygen reduction reaction (ORR) under alkaline condition and the results were compared with those of high nitrogen containing mesoporous carbon nitride MCN-1 and the commercially available Pt/C. Among the materials studied, the sample heat treated at 800 degrees C shows a high ORR activity with four electron process which is useful for fuel cell application. It is concluded that a high specific surface area, improved graphitic character and the nitrogen functional groups are essential for the enhancement of aforementioned ORR activity. This study of the synergistic effect of heat treatment in the preparation of graphitic NMC-G for the ORR is expected to be significant for the future research concerning the improvement of metal free, and carbon-based electro catalysts for fuel cell application.