Engineering surface framework TiO6 single sites for unprecedented deep oxidative desulfurization

Catalytic oxidative desulfurization (ODS) using titanium silicate catalysts emerges as an efficient technique for the complete removal of organosulfur compounds from automotive fuels. However, the precise control of highly accessible and stable framework Ti active sites remains highly challenging. Here we reveal for the first time by the density functional theory calculations that framework hexa-coordinated Ti (TiO6) species of mesoporous titanium silicates are the most active sites for ODS and lead to a lower-energy pathway of ODS. A novel method to achieve highly accessible and homogeneously distributed framework TiO6 active single sites at the mesoporous surface has been developed. Such surface framework TiO6 species exhibit an exceptional ODS performance. A removal of 920 ppm of benzothiophene (BT) is achieved at 60°C in 60 min, which is 1.67 times that of the best catalyst reported so far. For bulky molecules such as 4,6-dimethyldibenzothiophene (DMDBT), it takes only 3 min to remove 500 ppm of DMDBT at 60°C with our catalyst, which is 5 times faster than that with the current best catalyst. Such catalyst can be easily up-scaled and could find its concrete industrial application in ODS of bulky organosulfur compounds with minimized energy consumption and high reaction efficiency.