One-Step Carbonization of Monosaccharide and Dicyandiamide to Oxygen and Nitrogen Co-Doped Carbon Nanosheets for Electrocatalytic O2 Reduction to H2O2

The electrocatalytic reduction of O2 via two-electron reaction (2e-ORR) to H2O2 represents a promising alternative to the current anthraquinone process, since it is advantageous in the sustainable and decentralized production of H2O2. Herein, we report the development of oxygen and nitrogen-rich few-layered graphene-like materials (ms-dcda) by the one-step carbonization of biomass-sourced monosaccharides (D-glucose, D-fructose, D-galactose, D-ribose, D-xylose, L-arabinose, and D-mannose) with the aid of dicyandiamide for electrochemical O2 reduction to H2O2. The ms-dcda materials were porous and possessed wrinkled morphology typical of graphene nanosheets. In H2O2 production via 2e-ORR in an acidic electrolyte, these ms-dcda materials were all active and stable catalysts, among which glu-dcda derived from D-glucose and dicyandiamide displayed the lowest onset potential of 0.553 V and the highest selectivity of up to 91.6%. The catalyst was also highly stable in chronoamperometric tests. Selective chemical titration of the C–OH and C=O groups revealed that the latter is far more active and selective than the former in 2e-ORR. Moreover, a positive correlation between the contents of C=O and pyrrolic N and the H2O2 partial current suggests that the pyrrolic N group also contributes to 2e-ORR. This work affords a facile strategy for the sustainable fabrication of metal-free carbon-based catalysts efficient for H2O2 electrosynthesis.