How to select effective electrocatalysts: Nano or single atom?

Abstract Electrocatalysis is viewed as one of the most effective ways to mitigate the energy problems and produce fuels or value‐added chemicals in a gentle manner. However, duo to the limited electrochemical properties of various systems, there is an intensive search for highly efficient electrocatalysts by more rational control over the topographic structure, chemical structure, and electronic structure. At present, the development of electrocatalysts mainly includes two directions: (1) nanoparticle electrocatalysts, and (2) single atom site electrocatalysts (SACs). Nanoparticle and SACs display their own advantages, and have been widely studied in the field of electrocatalysis. Considering the state‐of‐the‐art progress for nanoparticles or SACs, the selection of effective electrocatalysts has been a topic of great research value. Therefore, this paper summarizes the advantages, commonalities, and problems of nanoparticle and SACs, as well as their developing methods and experiences. In addition, the selection of nanoparticle and SACs in electrocatalytic reactions was discussed from the aspects of their respective influencing factors, active sites and synergistic effect. Finally, the research of nanoparticle and single atom sites electrocatalysts were prospected, providing a general guidance for the selection of efficient electrocatalysts.