▎ 摘　　要

For the first time, graphene-supported N-doped carbon (G@NC) with a high degree of N doping was synthesized by in situ self-assembly of a glucaminium-based ionic liquid on pristine graphene under hydrothermal conditions. This 2D, metal-free nanohybrid exhibited much higher catalytic activity than most reported metal-free catalysts for the oxygen evolution reaction (OER) and even state-of-the-art Ir- and Ru-based catalysts because the high content of graphitic N greatly increased the number of OER-active sites, the pristine graphene significantly promoted the OER activity of the C sites adjacent to the graphitic N atoms, and N-doped graphitic carbon remarkably enhanced the charge-transfer rate. This work not only creates a facile and economical approach to controllably fabricate pristine-graphene-supported carbon with a high N-doping level for the development of highly efficient metal-free OER catalysts but also provides insight into the mechanisms for both the in situ self-assembly and the high OER catalytic activity of G@NC.