Aerobic Oxidation of Hydrocarbons Catalyzed by Mn-Doped Nanoporous Aluminophosphates(I): Preactivation of the Mn Sites
Aerobic Oxidation of Hydrocarbons Catalyzed by Mn-Doped Nanoporous Aluminophosphates(I): Preactivation of the Mn Sites
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DOI：
10.1021/cs100068t
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发表时间：
2011-01
期刊：
影响因子：
12.9
通讯作者：
Luis Gómez-Hortigüela;F. Corà;C. Catlow
中科院分区：
文献类型：
--
作者：
Luis Gómez-Hortigüela;F. Corà;C. Catlow
We apply state of the art electronic structure techniques, based on hybrid exchange-functionals in DFT and periodic boundary conditions, to unravel the reaction mechanism responsible for the initial stages of the aerobic oxidation of hydrocarbons catalyzed by Mn-doped aluminophosphates. In this preactivation step of the catalyst, which precedes the catalytic propagation cycle in which the final oxidation products (alcohol, aldehyde, and carboxylic acid) are formed, the MnIII ions initially present in the activated (calcined) catalyst are transformed by interaction with one alkane and one O2 molecule into new Mn-bearing species: a reduced MnII site and a MnIII···peroxo complex, which are active for the subsequent propagation cycle. The preactivation step has a high activation energy, calculated as 135 kJ/mol, explaining the long induction time observed experimentally. Our results further show that MnIII sites are able to produce the hydroperoxide intermediate from the reactants; however, this intermediate ...
