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The Bending Machine: CO2 Activation and Hydrogenation on d-MoC(001) and b-Mo2C(001) Surfaces. Posada Pérez, Sergio Viñes Solana, Francesc Ramírez, Pedro J. Vidal, Alba B. Rodríguez, José A. Illas i Riera, Francesc Teoria del funcional de densitat Diòxid de carboni Hidrogenació Molibdè Carburs Density functionals Carbon dioxide Hydrogenation Molybdenum Carbides 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. . 2017-12-01T11:50:33Z 2017-12-01T11:50:33Z 2014-06-09 2017-12-01T11:50:33Z info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Versió postprint del document publicat a: https://doi.org/10.1039/C4CP01943A Physical Chemistry Chemical Physics, 2014, vol. 16, p. 14912-14921 https://doi.org/10.1039/C4CP01943A (c) Posada-Perez, Sergio et al., 2014 info:eu-repo/semantics/openAccess Royal Society of Chemistry Articles publicats en revistes (Ciència dels Materials i Química Física)