Heterogeneous synergistic catalysts enable efficient catalytic transfer hydrogenation of nitro compounds via in-situ provided hydrogen

The selective hydrogenation of nitroarenes to their corresponding anilines is one of the most important transformation in environmental protection and fine chemicals production community since the nitro compounds are hazardous to environment and human health, as well as the functionalized anilines are industrially significant. Catalytic transfer hydrogenation (CTH) using an in-situ provided hydrogen donor has received considerable attention as an alternative to the traditional high-pressure hydrogenation process due to the merits of high efficiency, atomic economy and sustainability. However, the complicated elemental reaction network and the strict prerequisite are required to link the two successive reactions between the hydrogen evolution and subsequent hydrogenation. In this review, the designing and regulating strategies of synergistic (metallic) catalysts for CTH of nitroarenes were systematically summarized, which were based on the purpose to pursue a satisfactory catalytic efficiency and chemoselectivity to the terminal target. To provide in-depth recognition and understanding the role of functional sites in catalytic reduction of nitroarenes, herein this review presented the state-of-the-art of tandem catalysis, the proposed mechanisms for hydrogenation of nitroarenes with or without CTH, more importantly, the latest design strategies and cooperation effects of novel functional synergistic heterostructure catalysts of CTH of nitroarenes. The perspectives may contribute to the development of the fundamental theoretical framework of synergistic catalysts-driven CTH reactions.