Highly active MoS₂ on wide-pore ZrO₂-TiO₂ mixed oxides

Wide-pore ZrO₂-TiO₂ (Zr/Ti = 30/70) was prepared by low-temperature (273 K) sol-gel technique followed by solvo-treatment. Higher surface area (S_g ∼ 340 m² g^-1) and porosity (V_p ∼ 0.8 cm³ g^-1) were registered after solvo-treatment at 353 K (1 day) for samples calcined at 773 K. Wider pores (∼22 nm) but much lower S_g (∼80 m² g^-1) were observed when solvo-treatment was carried out at 513 K. Even larger pores with almost no additional S_g decrease were obtained by prolonging that stage. MoS₂ catalysts supported on binary oxides solvo-treated at 353 K showed increased intrinsic activity (by a factor of ∼3.3) in dibenzothiophene hydrodesulfurization (593 K and 5.6 MPa), as to that impregnated on conventional ZrO₂-TiO₂ (at 2.8 Mo atoms nm^-2). By itself, Mo sulfidability (as determined by XPS) seemed not to dictate the activity trends found. Surface Lewis acidity appeared to play a decisive role on HDS performance, probably by influencing both Mo sulfidability and dispersion. Highly-loaded catalysts (5.6 Mo atoms nm^-2) had decreased activity, probably due to lower MoS₂ dispersion. Additional characterization comprised chemical analysis (ICP), XRD, thermal analysis, acidity measurements (by pyridine FTIR) and UV-vis DRS. Tailoring ZrO ₂-TiO₂ texture, traditionally characterized by narrow micro-mesoporosity results promising in developing novel hydrotreating catalyst supports.