Mechanistic insights of methane conversion to ethylene over gallium oxide and gallium nitride using density functional theory
| Autor: | Chao-Jun Li, Kanchan Dutta, Jan Kopyscinski, Vishnu Chaudhari |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Reaction mechanism
Materials science Ethylene 010405 organic chemistry Process Chemistry and Technology chemistry.chemical_element Activation energy 010402 general chemistry 01 natural sciences Catalysis Methane 0104 chemical sciences chemistry.chemical_compound Adsorption chemistry Physical chemistry Density functional theory Physical and Theoretical Chemistry Gallium |
| Zdroj: | Molecular Catalysis. 482:110606 |
| ISSN: | 2468-8231 |
| Popis: | Density functional theory (DFT) was used to study the reaction mechanisms of direct non–oxidative methane (CH4) coupling to ethylene (C2H4) on gallium–based catalysts, GaN ( 1 1 ¯ 00 ) and Ga2O3 (001) surfaces. The adsorption energies of the reactants, the potential intermediates, and the products were calculated on both surfaces. For each of the catalysts three mechanistic pathways have been proposed and discussed. Reaction energies and activation energy barriers for the reactions were calculated and compared. The dissociative adsorption of methane on both surfaces is exothermic. By comparing the activation barrier of the rate-limiting step on both surfaces, the results showed that the C H bond cleavage of the CH3* species have the highest activation barrier for both catalysts. The results also illustrate that mechanism I is the most feasible pathway among the GaN ( 1 1 ¯ 00 ) and Ga2O3 (001) surfaces for the ethylene formation. In the case of Ga2O3 (001) H2O, CO, and CO2 are formed as products creating an oxygen vacancy on the Ga2O3 (001) surface. |
| Databáze: | OpenAIRE |
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