Single-atom catalysts (SACs) have attracted extensive attention because of their maximal atom utilization, unique electronic structure and high activity. Metal-organic frameworks (MOFs) could be used as perfect self-sacrificed precursors/templates for preparing SACs due to their uniformly distributed and spatially separated metal nodes and organic linkers as well as designable pore structures. Recently, numerous studies have been devoted to utilizing MOFs to prepare SACs through pyrolysis. Herein, this review summarizes the most recent strategies of turning selected MOFs into SACs, focusing on oxygen reduction reaction (ORR) catalysts. First, the inherent metal sites in MOFs are directly turned into single-atom sites via the high-temperature treatment with/without acid etching. Second, additional metal precursors are introduced into MOFs by various methods to further supplement active sites in the obtained SACs. Third, nonmetal heteroatom-rich (i.e., N, P and S) precursors are combined with MOFs to provide more coordination sites to anchor metal atoms. Finally, perspectives on future opportunities for selecting and designing MOFs as SAC precursors are also proposed.

单原子催化剂（SAC）由于其最大的原子利用率，独特的电子结构和高活性而备受关注。金属有机骨架（MOF）可以用作制备SAC的理想的自我牺牲前体/模板，这是因为它们的分布均匀且在空间上分隔开的金属节点和有机连接基以及可设计的孔结构。近来，许多研究致力于利用MOF通过热解制备SAC。在此，本综述总结了将选定的MOF转变为SAC的最新策略，重点是氧还原反应（ORR）催化剂。首先，MOF中固有的金属位点通过以下方式直接转变为单原子位点有/没有酸蚀的高温处理。第二，通过各种方法将额外的金属前体引入MOF，以进一步补充所获得的SAC中的活性位点。第三，非金属的富含杂原子的前体（即N，P和S）与MOF结合在一起，以提供更多的配位位点来锚定金属原子。最后，还提出了有关选择和设计MOF作为SAC前体的未来机会的观点。