Preparation of MoO3/TiO2 Catalysts with Eggshell and Uniform Mo Distribution by Water-Assisted Spreading of MoO3

Abstract

MoO 3 /TiO 2 catalysts were prepared by reaction of TiO 2 extrudates (140 m 2 g )1 ) with a MoO 3 /H 2 O slurry. The adsorption of molybdena species was strong; sharp, deep eggshell profiles of the Mo concentration were obtained. The hydrodesulfurization activity of saturated catalysts with a uniform Mo distribution (about 10 wt.% MoO 3 ) was at least the same as that of a sample prepared by conventional impregnation.

Slurry Impregnation of ZrO2 Extrudates: Controlled EggShell Distribution of MoO3, Hydrodesulfurization Activity, Promotion by Co

“…The correlations between (i) the saturated adsorption loadings of MoO 3 achieved over the zirconias studied and those achieved before over Al 2 O 3 [26] and TiO 2 [27], (ii) the specific surface area of those supports, and (iii) the time needed for the saturation of the supports are plotted in Fig. 3.…”

“…The particle size fraction (0.16-0.32 mm) of the catalysts with uniform and saturated loadings was used for the activity measurements because the laboratory apparatus enabled to test catalysts only in the form of grain. The [27], and triangles-Al 2 O 3 [26]. The numbers denote the external diameters in mm of the extrudates or balls studied Fig.…”

“…It was found that lower pH and a higher concentration of the solution, higher temperature, and accelerated drying promoted the formation of a shallow eggshell Mo profile. We, on the other hand, have proposed a new method, called ''slurry impregnation'' or ''water-assisted spreading'', which leads to a sharp and deep Mo eggshell in the Al 2 O 3 [26] or TiO 2 [27] extrudates. The method is based on the reaction of MoO 3 with the extrudates in water, and its main advantage lies in the fact that it does not produce any waste solution, only distilled water, during drying.…”

“…Techniques used in the literature [21][22][23][24][25][26][27] for the evaluation of Mo profiles in the extrudates or tablets include electron probe micro-analysis (EPMA) and reduction with a hydrazine-hydrochloric solution, with gaseous hydrogen or with a gaseous mixture of hydrogen and hydrogen sulfide. Quite recently, UV-vis and Raman microscopy [28][29][30][31][32][33], Tomographic Energy Dispersive Diffraction Imaging [34], and Multinuclear Magnetic Resonance Imaging [35] have been proposed as powerful tools for investigation into the preparation of Al 2 O 3 -supported Co-, Mo-, and P-containing hydrodesulfurization catalysts.…”

Preparation and Characterization of Mesoporous MoO3/TiO2 Composite with High Surface Area by Self-Supporting and Ammonia Method

“…Due to the synergetic effect between TiO 2 and molybdenum species, MoO 3 /TiO 2 composites present excellent catalytic performance compared with other molybdenum composites [2,6,7]. Furthermore, catalytic efficiency of composites also depends on their structure that is greatly influenced by the preparation process [8][9][10]. Generally, the composites with high surface area and mesoporous structure are considered to have better catalytic performance, especially in catalytic reactions of large molecules [11,12].…”