Affiliations: [a] Instituto Venezolano de Investigaciones Científicas, Centro de Química, Caracas, Venezuela | [b] Universidad Central de Venezuela, Facultad de Ciencias, Escuela de Química, Caracas, Venezuela | [c] Universidad Bolivariana de Venezuela, Programa de Formación de Grado en Gestión Ambiental, Caracas, Venezuela | [x] Centro de Química, Instituto Venezolano de Investigaciones Científicas, IVIC, Caracas, Venezuela | [y] Departamento de Química, Instituto Universitario de Tecnología FRP, Caracas, Venezuela
Correspondence:
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Corresponding author: David S. Coll, Instituto Venezolano de Investigaciones Científicas, Centro de Química, Caracas, Venezuela. E-mail: [email protected].
Abstract: The effect of the pre-adsorption of sulfur on the hexagonal-Mo2C-(001) surface in the hydrodechlorination (HDC) reaction of chlorobenzene was studied using density functional theory (DFT) calculations. The results related with the coordination modes and the adsorption energies of the aromatic molecule suggest that the main effect of the sulfur incorporation into the surface is to lead towards a weaker chlorobenzene adsorption that will benefit the continuity of the catalytic cycle and therefore to avoid the carbonization and chlorination of the catalyst. The study of the HDC mechanism was also performed and two different reaction paths were considered. The calculated energy barriers indicate that both mechanisms may occur at the normal reaction temperature (350°C). These latter approaches involve new roles of the superficial sulfur as atomic or radical hydrogen scavenger for the S-Hformation and as a precursor of the σ chlorobenzene coordination, necessary for effective hydrogenation in the proposed mechanisms.
