Recent advances in single-atom catalysts for CO oxidation

Single-atom catalysts (SACs) have received boosting attention due to their high atom utilization and incredible activities in a wide range of catalytic processes. Numerous SACs have been investigated for CO oxidation both experimentally and theoretically, including noble-metal catalysts (Pt, Au, Pd, etc.) and non-noble-metal catalysts (Fe, Co, Ni, etc.), in which the atomically dispersed metal atoms are anchored on supports via strong metal-support interactions. This unique structure of SACs contributes to activating the adsorbed CO and O2 and stabilizing the intermediates. Electron transfer between the metal atom and the support plays an important role in tuning the electronic structure, which can greatly influence the activity, selectivity, and stability of SACs. In this review, the design principles and synthesis methods of SACs for CO oxidation are discussed with emphasis on single-atom active sites and metal-support interactions. Four CO oxidation mechanisms over SACs are evaluated. Moreover, the challenges and future research directions for SAC-catalyzed CO oxidation are outlined.