Construction of Nitrogen-Doped Carbon Nanosheets for Efficient and Stable Oxygen Reduction Electrocatalysis

Two-dimensional nitrogen-doped carbon nanosheets (GCNS) have been fabricated through polymerization and carbonization using resorcinol, formaldehyde, aniline and graphene oxide as reactants. Herein, aniline serves as a nitrogen source for doping and graphene oxide is employed as the structure directing agent for nanosheet generation to engineer the structure. The resultant GCNS display a high surface area of 351 m(2) g(-1) and N doping content of 1.06 wt.%. Moreover, the obtained electrocatalysts demonstrate superior electrocatalytic oxygen reduction characteristics with an onset potential of 0.920 V versus reversible hydrogen electrode, diffusion-limiting current density (- 4.24 mA cm(-2)) and improved stability in an alkaline medium. The optimized oxygen reduction performance can be attributed to the rapid mass transfer and abundant active sites owing to the synergistic coupling effects arising from heteroatom dopants and structure modulation. On one hand, heteroatom doping provides enhance electronic conductivity with abundant defects and effective charge diffusion with improved surface wettability, which favors the electrocatalytic performances. On the other hand, the unique two-dimensional structure of the resultant GCNS provides good electrolyte accessibility and short ion/electron diffusion distances. This work demonstrates an effective construction of targeted heteroatom doping carbon nanosheets with surface functionalities and structure modification as carbon-based catalysts with advanced electrocatalytic performances.