CoMoNi Catalyst Texture and Surface Properties in Heavy Oil Processing. Part II: Macroporous Sepiolite-Like Mineral

A set of novel CoMoNi hydrotreating catalysts supported on sepiolite-like mineral and modified by H₃PO₄ have been prepared and studied in hydrodesulfurization (HDS) and hydrodemetallization (HDM) of heavy Tatar oil with extremely high viscosity and sulfur content. Catalysts had a multiphase composition, represented by calcium/magnesium oxides, silicates, or phosphates, and were found to be of great interest for studying the role of support surface properties in heavy oil hydrotreating. For monitoring the catalyst properties, all the samples have been investigated by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XFS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), CO- and CDCl₃-Fourier transform infrared (FTIR), mercury porosimetry, and N₂ adsorption methods. The catalyst with a small phosphate content showed higher initial HDS conversion due to the more developed specific surface area, increased Lewis acidity, and better active component distribution; however, the sulfur removal substantially reduced during 240 h on stream. The sample with a high amount of phosphates demonstrated better stability, higher HDM, and hydrocracking/hydroisomerization activity despite lower acidity and poor active phase dispersion that may be accounted for by the higher fraction of macropores