Rational design of single-atom catalysts for efficient hydrogenation of nitro compounds

The catalytic reduction of nitro compounds to amines is crucial in the fine and bulk chemical industries. Single-atom catalysts (SACs), featuring high atomic utilization and unique unsaturated coordination structures, hold significant promise in this field and have garnered considerable attention in recent years. Despite notable advancements, their performance remains insufficient for industrial applications. Therefore, it is imperative to develop strategies to enhance their catalytic performance, particularly in terms of activity. This review comprehensively summarizes recent progress in the application of SACs for the hydrogenation of nitro compounds. Firstly, the synthesis and characterization of SACs are briefly discussed. Secondly, strategies to enhance the catalytic activity of SACs are highlighted, including the design of single-atom sites. This involves optimizing the metal center and its microenvironment to improve intrinsic activity, as well as increasing the loading and utilization efficiency of single-atom sites to enhance apparent activity. Key insights from the reviewed works are summarized. Third, the hydrogenation mechanism on some SACs is briefly discussed. Finally, the challenges and prospects of SAC applications in the hydrogenation of nitro compounds are discussed.