Chemical Engineering Journal, Vol.328, 673-682, 2017
Ordered mesoporous silica-carbon-supported copper catalyst as an efficient and stable catalyst for catalytic oxidative carbonylation
Ordered mesoporous silica-carbon (MSC) nanocomposites with homogeneously distributed networks were synthesized by the triconstituent co-assembly method and used as supports of Cu catalysts for dimethyl carbonate (DMC) synthesis. The introduced silica contributes to the considerably increased pore size (similar to 5.8 nm), the enhanced metal-support interaction and high dispersion of Cu nanoparticles (similar to 3.8 nm) confined in the mesopores. An improved catalytic performance of Cu/MSC is achieved, reaching a DMC selectivity up to 90% at a methanol conversion of 1.5%, and a stable performance during five recycling runs. On the other hand, the benchmark Cu/MC catalyst undergoes a dramatic decrease of methanol conversion, from 1.3 to 1.0%, accompanied by a 27% reduction of DMC space-time yield (STYDMC). The mechanism through which the hybrid carrier affects the catalytic performance is analyzed using DFT calculations. The results show that the binding energy of Cu on MSC is greatly increased while the energy barrier to CO insertion for DMC formation is reduced evidently, thus enhancing the metal-support interaction and, in turn, the catalytic performance. (C) 2017 Elsevier B.V. All rights reserved.
Keywords:Mesoporous nanocomposites;Silica-carbon;Metal-support interaction;Stability;DFT calculation