Hidrogenación catalítica de CO2 sobre superficies de Fe puras y modificadas con Ni. Estudio teórico DFT

PATRICIA G. BELELLI; ANA ROSSI FERNÁNDEZ; LORENA MEIER; FUENTE SILVIA A; CAROLINA ZUBIETA; FERULLO, RICARDO M.

Congreso; XXII Congreso Argentino de Catálisis; 2022

The CO2 catalytic hydrogenation on three Fe-based surfaces was evaluated: on the monometallic Fe(111) terrace, the stepped Fe(310) surface, and the bimetallic Ni-Fe(111) terrace, in which a Fe atom of the first layer is substituted by a Ni atom. The study was performed using the density functional theory (DFT), and periodic conditions were employed to represent the extended catalytic surfaces. On Fe(111) and Ni-Fe(111), the formation of the HCOO species takes place by surpassing two activation barriers from the most stable CO2 adsorption modes. The first one corresponds to the H atom migration to be located close to the adsorbed CO2, and the second one to the formation of the C-H bond to produce HCOO, both with similar energetic requirements. On Fe(310), the process occurs in only one step but with a higher barrier. By comparing these results with those previously computed for CO2 dissociation, it is possible to conclude that on Fe(111) the predominant reaction will be the HCOO formation; on Fe(310), this reaction will be competitive with that of CO2 dissociation. On Ni-Fe(111), the preferred mechanism will be the HCOO production, although CO2 dissociation could occur in minor proportion.