▎ 摘　　要

Covalent functionalization of two-dimensional materials is a versatile tool to induce deep changes in their initial properties leading to new functionalities. Unfortunately, in the case of graphene its poor chemical reactivity turns this task rather difficult from the practical point of view. In this work, we show how the adsorption of external species can be controlled by substitutional nitrogen atoms properly distributed through the graphene layer. Nitrogen atoms can be experimentally incorporated in the graphene lattice with high precision and tunable concentration and they can be used as active sites to trigger an ordered functionalization. By means of first-principles calculations we study the adsorption of single and multiple oxygen atoms in the vicinity of substitutional N defects, revealing a rich scenario regarding adsorption configurations and electronic properties. In particular, we find a stable structure involving three oxygen atoms that induces a robust magnetic behavior in the graphene layer. The great chemical variability found in the oxygen-decorated N-doped structures presented in this study constitutes a valuable platform for the future development of graphene-based electronic and sensing devices. (C) 2019 Elsevier Ltd. All rights reserved.