Bifunctional catalysts supported on modified vermiculite for the hydroconversion of decane. Effect of the metal phase (Mo or W) and promoters (Ni or Co)

Abstract

In this study, NiMo, CoMo, NiW and CoW catalysts were synthesized and supported on delaminated vermiculite modified with Al-Zr and Al-Ce to modulate their acidic properties. The metal phase and the promoters were incorporated by means of the wet impregnation method. The catalysts obtained were characterized using X-ray diffraction (XRD), N2 adsorption, temperature-programmed reduction (H2-TPR) of the unreduced and pre-reduced catalysts, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance infrared spectroscopy with a probe molecule (NH3-DRIFTS). The catalytic performance was evaluated in the conversion of decane. The main differences in catalytic performance were attributed to the metal and the content used. The Mo catalysts exhibited low conversion temperatures compared to those of the W catalysts, which was correlated with the greater number of reducible species at lower temperatures. The catalysts with a promoter/metal ratio of 0.4 presented the best catalytic performance, which was attributed to the improved formation of NiMo or CoMo species on the surface of the solids. The major role of the acid properties in the conversion of alkanes was corroborated, with the Co catalysts supported on the mineral modified with Al-Ce presenting the best catalytic activity compared to that of the catalysts containing Ni as a promoter of the metal phase and Al-Zr as an acidity potentializer.