Al-modified dendritic mesoporous silica nanospheres-supported NiMo catalysts for the hydrodesulfurization of dibenzothiophene: Efficient accessibility of active sites and suitable metal–support interaction

Dendritic mesoporous silica nanospheres (DMSNs) with center–radial pore structure were successfully fabricated via an anion-assisted method. Al-modified DMSNs-supported NiMo catalysts were prepared and used for hydrodesulfurization (HDS) of dibenzothiophene (DBT). The DMSNs supports and corresponding supported NiMo catalysts were characterized by SEM, TEM, N2 adsorption/desorption, electron tomography (ET), 27Al NMR, NH3-TPD, UV–Vis spectroscopy, XPS, H2-TPR, Raman spectroscopy, and Pyridine-FTIR spectra. The average pore diameter of DMSNs is around 26.4 nm, which is helpful for eliminating the diffusion resistance of S-containing compounds. The center–radial pore structure of DMSNs, confirmed by ET measurement, is beneficial for enhancing the accessibility of active sites in the pore channels. The incorporation of aluminum into the framework of DMSNs can improve the acidity and modulate the metal–support interaction. Consequently, NiMo/Al-DMSNs catalysts exhibited higher HDS conversions (97.9%) for DBT than commercial NiMo/γ-Al2O3 catalyst. The superior catalytic activity of NiMo/Al-DMSNs results from a perfect combination of large center–radial pore channels, increased acidity, suitable metal–support interaction, and good dispersion/accessibility of active metals.