Hydroconversion of n-Decane over Ni-Mo Supported on Modified Halloysite Catalysts

The performance of a series of bifunctional catalysts consisting of Ni-Mo species impregnated on natural halloysite nanotubes or treated with mineral acids was evaluated in the n-decane hydroconversion reaction (isomerization and cracking). To establish the main physicochemical characteristics of the solids and to find their correlation with the synthesis parameters and the catalytic performance, a set of techniques was used, including X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM, respectively), N-2 adsorption-desorption isotherms, temperature-programmed reduction (H-2-TPR), temperature-programmed desorption of ammonia (NH3-TPD), and in situ infrared spectroscopy, in diffuse reflectance mode, using NH3 as a probe molecule (NH3-DRIFTS). The results allow concluding that the acid treatment on the 1:1 clay mineral (halloysite) considerably improved its surface area and acidity, without significantly compromising the nanotubular structure and macro mesoporosity of the starting mineral. The modifications allowed obtaining catalysts with high mesoporosity, which are active in the hydroconversion reaction of n-decane. The materials synthesized from the halloysitic supports treated with H2SO4 are catalysts with better performance, possibly due to the improvement of the textural and acidic properties of the support, which also should favor the dispersion of the hydrogenating phases (Ni-Mo).