6533b7d7fe1ef96bd1268fd4
RESEARCH PRODUCT
DFT insights into the oxygen-assisted selective oxidation of benzyl alcohol on manganese dioxide catalysts
Antonio PrestianniFrancesco FerranteLaura GueciRoberto Di ChioAntonio F. PattiFrancesco ArenaDario Ducasubject
inorganic chemicalsInorganic chemistrychemistry.chemical_elementAlcoholManganese010402 general chemistry01 natural sciencesRedoxCatalysisInorganic Chemistrychemistry.chemical_compoundAdsorptionBenzyl alcoholMaterials ChemistryReactivity (chemistry)Physical and Theoretical ChemistryReaction mechanismBenzoic acidDFT analysi010405 organic chemistryActive siteorganic chemicalsMnO2 catalyst0104 chemical scienceschemistrySettore CHIM/03 - Chimica Generale E InorganicaBenzyl alcoholActive sites; Benzyl alcohol; DFT analysis; MnO; 2; catalyst; Reaction mechanism; Selective oxidationSelective oxidationdescription
Abstract The reactivity pattern of the MnO2 catalyst in the selective aerobic oxidation of benzyl alcohol is assessed by density functional theory (DFT) analysis of adsorption energies and activation barriers on a model Mn4O8 cluster. DFT calculations predict high reactivity of defective Mn(IV) sites ruling a surface redox mechanism, L-H type, involving gas-phase oxygen. Bare and promoted (i.e., CeOx and FeOx) MnOx materials with high surface exposure of Mn(IV) sites were synthesized to assess kinetic and mechanistic issues of the selective aerobic oxidation of benzyl alcohol on real catalysts (T, 333–363 K). According to DFT predictions, the experimental study shows: i) comparable activity of bare and promoted catalysts due to surface Mn(IV) sites; ii) the catalytic role of oxygen-atoms in the neighboring of active Mn(IV) sites; and iii) a 0th-order dependence on alcohol concentration, diagnostic of remarkable influence of adsorption phenomena on the reactivity pattern. Evidences of catalyst deactivation due to the over-oxidation of benzyl alcohol to benzoic acid, acting as poison of the active sites, are discussed.
year | journal | country | edition | language |
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2020-10-01 |