Hierarchical porous HPW/titania-silica material with superior adsorption-catalytic oxidation activity for multi-ring thiophenic sulfur compounds

• Published in: New journal of chemistry Vol. 44; no. 12; pp. 4942 - 4951
• Main Authors: Du, Yue, Zhou, Lina, Liu, Zhenhui, Lei, Jiaheng
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 28.03.2020
• Subjects: Adsorption; Ammonia; Anatase; Catalysts; Catalytic oxidation; Desulfurizing; Dibenzothiophene; Lewis acid; Mass transfer; Microspheres; Oxidation; Porous materials; Silicon dioxide; Specific surface; Structural hierarchy; Sulfur compounds; Surface area; Surface chemistry; Titanium; Titanium dioxide; X ray photoelectron spectroscopy
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c9nj05793e

A series of hierarchically structured HPW/titania-silica catalysts with micro-meso-macroporous structures and high specific surface areas are prepared through a co-precipitation method, adopting a cationic surfactant, STAB, and monodisperse PS microspheres as double templates. The effects of silicon content on the specific surface area, mesoporous ordering, crystalline phase, and surface acidity of Ti-Si composites have been investigated by using SEM, TEM, XRD, BET, XPS, NH 3 -TPD, UV-Vis/DRS, and FT-IR measurements. These results suggest that the as-fabricated catalyst with 80% SiO 2 content possesses a relatively high S BET (1001.1 m 2 g −1 ), crystal characteristics of anatase TiO 2 , and a weak Lewis acid site on the material surface. Keggin-type H 3 P 12 W 40 is homogeneously dispersed in the SiO 2 -TiO 2 framework. In the oxidative desulfurization (ODS) reaction, 500 ppm dibenzothiophene (DBT) in the model fuel can be completely removed within 60 min under the conditions of catalyst dosage = 0.05 g, T = 30 °C, and O/S = 4. The excellent ODS performance is due to the advantages of interconnected macropores, short-range-ordered mesopores, abundant micropores, and surface acidity of the catalyst, which facilitate the mass transfer of DBT, and adsorption and diffusion process in the pore channel. The hierarchical micro-meso-macroporous structure of the catalyst also benefits the exposure of the inner surface area, and increases the amount of accessible active sites and exposure of the inner surface. Moreover, the as-fabricated catalyst can be reused for 10 cycles without a significant decrease in desulfurization efficiency. HPW/titania-silica catalysts with micro-meso-macroporous structures and high specific surface areas are prepared and applied as oxidative desulfurization catalysts.