Dendritic micro-mesoporous composites with center-radial pores assembled by TS-1 nanocrystals to enhance hydrodesulfurization activity of dibenzothiophene and 4,6-dimethyldibenzothiophene

摘要

A novel dendritic composite (TD) with an open center-radial pore structure using TS-1 nanocrystals as microporous precursors was successfully synthesized by a facile method. TS-1 nanocrystals were embedded into the framework of dendritic mesoporous silica nanospheres (DMSNs) to form Si-O-Ti bonds, which was beneficial for generating more S vacancies of MoS2 active phases. The NiMo/TD-2 catalyst had a larger surface area and stronger metal-support interaction, resulting in higher sulfidation and dispersion degrees of MoS2 active phases over the sulfided NiMo/TD-2 catalyst, which was consequently favored to improve the hydrodesulfurization (HDS) activity of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). Furthermore, the NiMo/TD-2 catalyst with an SiO2/TiO2 molar ratio of 150 exhibited higher HDS performance for DBT and 4,6-DMDBT than other NiMo/TD catalysts and the commercial NiMo/Al2O3 catalyst. Moreover, the NiMo/TD-2 catalyst possessed more Bronsted and Lewis acid sites, thus promoting the hydrogenation of DBT and the isomerization of 4,6-DMDBT. (C) 2020 Elsevier Inc. All rights reserved.