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Tang D.,Leshan Normal College | Tang D.,Center for Molecular Design | Zhu L.,Sichuan University | Hu C.,Sichuan University
RSC Advances | Year: 2012

The mechanism by which benzene is converted to phenol through hydroxylation, catalyzed by vanadium in CH 3CN is explored at the B3LYP(IEF-PCM)//B3LYP/6-311G(2d,2p) level. Three candidate catalysts are used to simulate the catalytic cycle. The solvent effectively reduces the free energy barriers of the C-H bond activation step. The binuclear vanadium species is predicted to be the main form of the operative catalyst. The cooperative role of the two vanadium centres and the dynamic charge distribution of the binuclear vanadium species are found to increase the catalytic activity. The conservation of aromaticity for the phenyl ring in the benzene or phenyl ligand is essential for the benzene hydroxylation. © 2012 The Royal Society of Chemistry. Source

Tang D.,Center for Molecular Design | Chen Z.,Haimen Wisdom Pharmaceutical Co. | Hu J.,Center for Molecular Design | Sun G.,Center for Molecular Design | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2012

The mechanism of the CO oxidation promoted by a neutral Ag55 cluster was investigated extensively, using density functional theory calculations. The CO oxidation process catalyzed by anionic and cationic Ag 55 clusters was also studied, to clarify the effects of the charge state. The Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms were discussed in detail. Six reaction pathways were found for the Ag 55-mediated CO oxidation. It was found that the ER mechanism competed with the LH mechanism. The rate-limiting step of the CO oxidation was the reaction of CO with the Ag55O species. All of the anionic, neutral, and cationic Ag55 clusters were able to promote CO oxidation at low temperatures. The present results enrich our understanding of the catalytic oxidation of CO by nano-sized Ag-based catalysts. © 2012 the Owner Societies. Source

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