▎ 摘　　要

Single atom catalysts (SACs) as a kind of bright star catalyst have attracted great attention, constituting a series of intriguing properties for catalytic reactions. Herein, a simple and ingenious strategy is developed for the fabrication of SACs via atomic filtration during a solid diffusion process under the assistance of graphene oxide membranes (GOMs). First, driven by the heat treatment, the Fe species (atoms, cluster, or particles) are emitted from Fe foam diffused through the GOMs. By elaborately modulating the layer numbers of the GOM and their interlayer spacing, the GOM could exclude the cluster and particles of the Fe species. Thus, the permeable single Fe atoms were trapped by defective N-rich sites, producing isolated Fe site catalyst (Fe SAs/N-C). The fabricated SACs exhibited an excellent catalytic performance for the oxygen reduction reaction (ORR). Furthermore, this strategy can be easily expanded to prepare other SACs, such as Co SAs/N-C and Ni SAs/N-C.