Advances of Single-Atomic Cobalt Catalysts in Liquid-Phase Selective Oxidative Reactions.

Single-atom catalysts (SACs) composed of atomically dispersed metal-active sites embedded in supporting substrates are attracting increasing attention in liquid-phase selective oxidation reactions with joint merits of both advanced catalytic efficiency and high stability. Co-based SACs present superior performance in several model oxidative reactions against many other metals, thus they are recognized as a promising solution to the current high-cost noble-metal catalysts required for the synthesis of fine chemicals. In this review, the up-to-date research on the synthesized Co-SACs in selective oxidation applications is summarized. The strategies of the preparation of Co-SACs with diverse Co-loading levels and well-tuned morphologies and chemical structures are showcased, as well as the characterization techniques of the SACs. The applications of Co-SACs in a series of selective oxidation reactions and the influence of different oxidants on the overall reaction efficiency are discussed. In addition, the progress of the mechanism exploration involving active-site identification, catalytic activation of oxidants, and oxidation pathway elucidation is highlighted. Meanwhile, the existing challenges and the future efforts for the development of the Co-SAC reaction system in selective oxidation processes are outlined.