4,6-Dimethyl-dibenzothiophene conversion over Al2O3–TiO2-supported noble metal catalysts

• Published in: Materials chemistry and physics 2011-03, Vol.126 (1-2), p.237-247
• Main Authors: Núñez, Sara, Escobar, José, Vázquez, Armando, Reyes, José Antonio de los, Hernández-Barrera, Melissa
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Catalysis; Catalysts; Metal particles; Mixed oxides; Palladium; Platinum; Titanium dioxide
• ISSN: 0254-0584
• DOI: 10.1016/j.matchemphys.2010.11.032

a- Al2O3 and Al2O3-TiO2 (molar ratio Al/Ti=2, AT2) mixed oxides were pore-filling impregnated to obtain Pd, Pt and Pd-Pt catalysts with a arrow right 41wt% nominal metal loading. a- Reduced catalysts were tested in the 4,6-dimethyl-dibenzothiophene hydrodesulfurization (HDS). a- In Pd-containing materials, TiO2 incorporation into the alumina support was favorable to the catalytic activity of noble metal catalysts. a- Enhanced intrinsic activity (per exposed metallic site) was obtained in Pt-containing catalysts supported on the AT2 mixed oxide. a- Yield to different products over various catalysts seemed to be strongly influenced by metallic particles dispersion. Al2O3 and Al2O3-TiO2 (molar ratio Al/Ti=2, AT2) mixed oxides were synthesized using a low-temperature sol-gel method and were further pore-filling impregnated to obtain Pd and Pt catalysts with a arrow right 41wt% nominal metal loading. Simultaneous impregnation was used to prepare bimetallic materials at Pd:Pt=80:20. Solids characterization was carried out by N2-physisorption, high-resolution transmission electron microscopy (HR-TEM and E-FTEM), X-ray diffraction, temperature-programmed reduction and CO-chemisorption. Reduced (350A degree C, H2 flow) catalysts were tested in the 4,6-dimethyl-dibenzothiophene hydrodesulfurization (HDS) (in n-dodecane, at 300A degree C and 5.5MPa, batch reactor). In Pd-containing materials, TiO2 incorporation into the alumina support was favorable to the catalytic activity of noble metal catalysts, where bimetallic Pd-Pt with AT2 carrier had the highest organo-S compound conversion. Enhanced intrinsic activity (per exposed metallic site) was obtained in Pt-containing catalysts supported on the AT2 mixed oxide (as compared to alumina-supported ones). Yield to different products over various catalysts seemed to be strongly influenced by metallic particles dispersion.