Regresar

Use of electron paramagnetic resonance techniques in the study of catalysts based on vanadium: Catalytic hydrotreating

Abstract:

Electron Paramagnetic Resonance (EPR) is a sensitive spectroscopic method for the determination of the geometric and electronic structure, the dynamics and the spatial distribution of paramagnetic species in catalytic systems, respecting to the oxidation state, support effects and changes in the surface catalytic after reaction. This technique had been employed in order to study a new synthesis route to prepared vanadium nanoparticles catalyst supported on activated carbon, γ-alumina, silica and titania. The bimetallic systems: NiV/C y VMo/C also we prepared. The catalysts were tested in Hydrotreating reactions (HDS, HYD, and HDN). EPR measurements shows the presence of V 4+ species on the oxides supports, it can be found as isolated species or clusters, being depending of the support used. Moreover, the EPR study shows the chemical environment changes around the metallic particles after HDS, HYD and HDN reactions. Not signal related with V4+ species were found when the support was carbon, but an increase in the dangling bonds was find. It was proposed that this paramagnetic species could be related with the catalytic activities in the Hydrotreating reactions studies, decreasing its behavior catalytic.