Search results for "DFT analysi"
showing 4 items of 4 documents
DFT and kinetic evidences of the preferential CO oxidation pattern of manganese dioxide catalysts in hydrogen stream (PROX)
2022
Abstract The oxidation functionality of Mn(IV) sites has been assessed by density functional theory (DFT) analysis of adsorption and activation energies of CO, H2 and O2 on a model Mn4O8 cluster. DFT calculations indicate that Mn(IV) atoms prompt an easy CO conversion to CO2 via a reaction path involving both catalyst and gas-phase oxygen species, while much greater energy barriers hinder H2 oxidation. Accordingly, a MnCeOx catalyst (Mnat/Ceat, 5) with large exposure of Mn(IV) sites shows a remarkable CO oxidation performance at T ≥ 293 K and no H2 oxidation activity below 393 K. Empiric kinetics disclose that the catalyst-oxygen abstraction step determines both CO and H2 oxidation rate, al…
DFT insights into the oxygen-assisted selective oxidation of benzyl alcohol on manganese dioxide catalysts
2020
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…
Antimicrobial Activity, in silico Molecular Docking, ADMET and DFT Analysis of Secondary Metabolites from Roots of Three Ethiopian Medicinal Plants
2021
Mathewos Anza,1 Milkyas Endale,1 Luz Cardona,2 Diego Cortes,3 Rajalakshmanan Eswaramoorthy,1 Jesus Zueco,4 Hortensia Rico,4 Maria Trelis,5 Belen Abarca2 1Department of Applied Chemistry, School of Applied Natural Science, Adama Science and Technology University, Adama, Ethiopia; 2Department of Organic Chemistry, Faculty of Chemistry, University of Valencia, Burjassot, Spain; 3Department of Pharmacology, Faculty of Pharmacy, University of Valencia, Burjassot, Spain; 4Department of Microbiology and Ecology, Faculty of Pharmacy, University of Valencia, Burjassot, Spain; 5Parasites and Health Research Group, Department of Pharmacy, Pharmaceutical Technology and Parasitology, Faculty of Pharmacy…
Photochemical intermediates of trans-Rh(CO)L2Cl where L=PMe3, PBu3, and i-Pr2HN and cis-Rh(CO)2(i-Pr2HN)Cl in frozen organic glasses
2002
International audience; The Nujol glass matrix photolyses of Rh(CO)(PMe3)2Cl (1), Rh(CO)(PBu3)2Cl (2), Rh(CO)2(i-Pr2HN)Cl (3), and Rh(CO)(i-Pr2HN)2Cl (4), have been examined. Phototolysis of 1 (λirr>400 nm) and 2 (350<λirr<400 nm) give new species, A, with carbonyl stretching bands slightly below the parent bands. In the case of 1 this species appears to give rise to a second product, C, upon either extended photolysis or annealing. High-energy photolysis of 1, 2, and 4, result in loss of CO and formation of an IR silent species, RhL2Cl. In the case of 1 a new carbonyl species, B, is observed upon high-energy photolysis or annealing of a matrix containing CO and Rh(PMe3)2Cl. B may be conver…