Using periodic density functional theory calculations, the catalytic reduction of NO molecules is studied over a Al- or Si- anchored graphene oxide (GO). It is found that the epoxy groups over GO could trap the Al or Si atom with a large adsorption energy and high diffusion barrier. Both “direct dissociation” and “dimer” mechanisms are studied for the reduction of NO molecules to N 2 O over these surfaces. According to our results, the NO reduction over Al or Si anchored GO proceeds through a dimer mechanism, due to its low activation energy. Moreover, the dimer mechanism should be more favorable than the direct dissociation since the adsorption energy of the (NO) 2 dimer is found to be larger than that of a single NO monomer. Besides, the Si-anchored GO exhibits higher catalytic activity than the Al-anchored one. We hope that results of present study provide a valuable guidance on design graphene-based single-atom catalysts to remove toxic NO molecules.