Regulating pore structures of carbon supports toward efficient selective hydrogenation of o-chloronitrobenzene on Pt nanoparticles

Abstract

A series of Pt nanoparticles (NPs) confined inside ordered mesoporous carbon (OMC) were prepared for catalytic hydrogenation of o-chloronitrobenzene. The improved activity as well as selectivity was achieved by enhancing mass diffusion of reactant and targeted product. It was found that most of the Pt NPs were homogeneously dispersed inside the mesoporous channels of obtained Pt/OMC samples while Pt NPs were mainly distributed on the external surface of commercial activated carbon (AC) with an aggregation to a certain extent. The combination of surface oxygen-containing groups and ordered mesoporous environment was responsible for the formation of small-sized Pt NPs in Pt/OMC. Notably, the body-centered cubic mesoporous carbon (CMC-600) supported Pt catalyst gave 100% o-chloronitrobenzene conversion with 100% selectivity to the target product under mild conditions. This outstanding catalytic performance could be attributed to the synergetic effect between the unique porosity of CMC and small-sized Pt NPs stabilized inside the ordered mesopores. In addition, the Pt/CMC catalyst showed excellent stability and it could be reused for at least 5 times without significant loss of activity and selectivity. This study provided theoretic guidance for rational design of supported Pt catalysts for the chemoselective hydrogenation of halogenated nitrobenzenes.