Partic. vol. 10 no. 4 pp. 468-474 (August 2012)
doi: 10.1016/j.partic.2012.01.001

Hydrodesulfurization catalyst prepared by urea-matrix combustion method

Dongmei Jiao^{a, b}, Yeyong Ma^c, Fahai Cao^{a, *}

fhcao@ecust.edu.cn

Abstract

Co–Mo/γ-Al₂O₃–TiO₂ hydrodesulfurization (HDS) catalyst samples prepared by a urea matrix combustion (UMxC) method, were evaluated in a stainless tubular fixed-bed reactor, with thiophene, benzothiophene and dibenzothiophene in xylene as model feedstocks. The samples were pre-sulfurized using a cyclohexane solution of 3% CS₂ and then tested for the HDS reaction. The test results were compared with catalysts prepared by conventional methods involving sequential impregnation (SI) and co-impregnation (CI). The catalysts were characterized using X-ray diffraction (XRD), laser Raman spectroscopy (LRS), high resolution transmission electron microscopy (HRTEM) and N₂ physisorption, showing that the UMxC catalyst had higher pore volume and surface area than those prepared by the CI and SI methods. The UMxC method increased metal loading and avoided formation of inert phase, e.g., β-CoMoO₄, for the HDS reaction, suggesting that UMxC method is superior to the conventional impregnation techniques. TiO₂ promoter made particles on the catalyst surface closer and alleviated the interaction between molybdenum oxide and the support, and facilitated the formation of well-dispersed Co- and Mo-oxo species on catalyst surface, thus resulting in higher HDS catalytic activity than pure γ-Al₂O₃ support without modifiers. Consequently, the addition of TiO₂ obviously improved the HDS conversion of dibenzothiophene.

Graphical abstract

Keywords

Hydrodesulfurization; Co–Mo catalyst; Al₂O₃–TiO₂ support; Urea-matrix combustion method; Preparation