Coprinus comatus-derived nitrogen-containing biocarbon electrocatalyst with the addition of self-generating graphene-like support for superior oxygen reduction reaction

The development of nitrogen-rich biomass-derived carbon catalysts provides an attractive perspective to substitute for Pt-based electrocatalysts for oxygen reduction reaction (ORR). We here report a facile strategy for synthesis of a nitrogen-doped biocarbon/graphene-like composite electrocatalyst by pyrolyzing a solid-state mixture of coprinus comatus biomass and melamine under nitrogen protection. The graphtic carbon nitride formed by polycondensation of melamine at 600 °C acts as a self-sacrificing template to generate the nitrogen-doped graphene-like sheet, which can function as an inserting agent and self-generating support. The composite catalyst exhibits the most promising catalytic activity towards the four-electron ORR with a half-wave potential of around 0.83 V (vs. RHE), and more excellent stability and tolerance to methanol/ethanol compared to the commercial Pt/C catalyst. It is interestingly found that both a higher content of nitrogen and a larger ratio of graphitic-nitrogen species, which may derive from self-addition of graphene-like support into the catalyst, can effectively improve the electrocatalytic activity. The planar N group may be the nitrogen functionality that is most responsible for maintaining the ORR activity in alkaline medium. This study can largely encourage the exploration of high-performance carbon-based catalysts from economical and sustainable fungus biomass.