The Bending Machine: CO2 Activation and Hydrogenation on d-MoC(001) and b-Mo2C(001) Surfaces.
The adsorption and activation of a CO2 molecule on cubic d-MoC(001) and orthorhombic b-Mo2C(001) surfaces have been investigated by means of periodic density functional theory based calculations using the Perdew-Burke-Ernzerhof exchange-correlation functional and explicitly accounting for (or neglec...
| Autores: | , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/118384 |
| Acceso en línea: | https://hdl.handle.net/2445/118384 |
| Access Level: | acceso abierto |
| Palabra clave: | Teoria del funcional de densitat Diòxid de carboni Hidrogenació Molibdè Carburs Density functionals Carbon dioxide Hydrogenation Molybdenum Carbides |
| Sumario: | The adsorption and activation of a CO2 molecule on cubic d-MoC(001) and orthorhombic b-Mo2C(001) surfaces have been investigated by means of periodic density functional theory based calculations using the Perdew-Burke-Ernzerhof exchange-correlation functional and explicitly accounting for (or neglecting) the dispersive force term description as proposed by Grimme. The DFT results indicate that an orthorhombic b-Mo2C(001) Mo-terminated polar surface provokes the spontaneous cleavage of a C-O bond in CO2 and carbon monoxide formation, whereas on a b-Mo2C(001) C-terminated polar surface or on a d-MoC(001) nonpolar surface the CO2 molecule is activated yet the C-O bond prevails. Experimental tests showed that Mo-terminated b-Mo2C(001) easily adsorbs and decomposes the CO2 molecule. This surface is an active catalyst for the hydrogenation of CO2 to methanol and methane. Although MoC does not dissociate C-O bonds on its own, it binds CO2 better than transition metal surfaces and is an active and selective catalyst for the CO2+3H2-> CH3OH + H2O reaction. Our theoretical and experimental results illustrate the tremendous impact that the carbon/metal ratio has on the chemical and catalytic properties of molybdenum carbides. This ratio must be taken into consideration when designing catalysts for the activation and conversion of CO2. . |
|---|