Highly Active and Chemoselective Reduction of Halogenated Nitroarenes Catalyzed by Ordered Mesoporous Carbon Supported Platinum Nanoparticles

Highly dispersed Pt nanoparticles (∼2.2 nm) on ordered mesoporous carbon (Pt/CMK-3–HQ) were first prepared through a two-step impregnation route with aqueous solutions of 8-hydroxyquinoline (8-HQ) and H₂PtCl₆, respectively. The Pt/CMK-3–HQ quantitatively converted various halogenated nitroarenes to the corresponding haloanilines using hydrazine hydrate with unprecedented activities (e.g., turnover frequency for o-chloronitrobenzene was 30.2 s^–1) and exhibited high stability with 20 cycles without decrease in catalytic efficiency. The high activity and chemoselectivity of Pt/CMK-3–HQ were attributed to the cooperation effect between Pt and N species, promoting cleavage of hydrazine to generate more Pt–H^– and N–H⁺ species for reduction of nitro groups and weakening the interaction between halogen groups and Pt atoms for activation of C-halogen bonds.