Multifunctional design of single-atom catalysts for multistep reactions

With the merits of high atom utilization, low cost, unique and tunable microstructures, as well as the particular catalytic behaviors, single-atom catalysts (SACs) have gained worldwide interest and achieved great advancements in heterogeneous catalysis recently. However, catalyzing an intricate multistep reaction is usually challenging for one single-atom center, in which case multiple catalytic sites are needed. In this review, the experimental and computational advances in the construction strategies of multi-active-site SACs will be summarized and classified as single-atom/single-atom, single-atom/nanoparticle and single-atom/support multifunctional catalysts. The microstructures of different active centers and their catalytic behaviors during catalysis will be emphatically highlighted. Moreover, the confronting challenges and opportunities of this field will be discussed. This review will place emphasis on the design of multifunctional SACs for multistep reactions, which will shed light on their further development in heterogeneous catalysis and beyond.