▎ 摘　　要

A facile bottom-up method is reported here for the fabrication of N-doped graphene for oxygen reduction. It consists of a two-step calcination strategy and uses alpha-hydroxy acids (AHAs) as carbon source and melamine as nitrogen source. Three different AHAs, malic acid, tartaric acid, and citric acid, were chosen as the carbon sources. The prepared N-doped graphenes have a typical thin layered structure with a large specific surface area. It was found that the N content in the obtained N-doped graphenes varies from 4.12 to 8.11 at. % depending on the AHAs used. All of the samples showed high performance in oxygen reduction reaction (ORR). The N-doped graphene prepared from citric acid demonstrated the highest electrocatalytic activity, which is comparable to the commercial Pt/C and exhibited good durability, attributing to the high pyridinic N content in the composite.