Precise tuning the CoMoOx/Al2O3 and CoMoSx/Al2O3 interfacial structures for efficient hydrodesulfurization of dibenzothiophene. (1st October 2021)

• Record Type: Journal Article
• Authors: Wang, Pengcheng; Liu, Jun; Liu, Guo; Xu, Peiwen; Feng, Xinzhen; Ji, Weijie; Gao, Yulan; Au, Chak-Tong
• Is Part Of: Fuel. Volume 301(2021)
• Publication Date: 2021-10-01
• Subjects: Alumina morphology -- Mo-Co oxide -- Mo-Co sulfide -- Interfacial structure -- Hydrodesulfurization -- Dibenzothiophene; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2021.121042
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: ● Morphologically uniform γ-Al2 O3 hexagonal plates, stacked hexagonal plates, and rods controllably prepared. ●The specific (1 1 0), (1 0 0)/(1 1 1), and poly-crystalline facets of γ-Al2 O3 supports available for catalyst design. ●Precise tuning the oxidic and sulphurated interfacial structures with distinct γ-Al2 O3 facets and Co/Mo loadings. ●Highest content of MoS2 /Co9 S8 /CoMoS and highest activity of DHS of DBT on the (1 1 0) facet-based catalyst. ●Enhanced MoS2 -CoMoS/MoS2 -Co9 S8 conjunction and synergism more efficient for the target reaction. Highlights: Morphologically uniform γ-Al2 O3 hexagonal plates, stacked hexagonal plates, and rods controllably prepared. The specific (1 1 0), (1 0 0)/(1 1 1), and poly-crystalline facets of γ-Al2 O3 supports available for catalyst design. Precise tuning the oxidic and sulphurated interfacial structures with distinct γ-Al2 O3 facets and Co/Mo loadings. Highest content of MoS2 /Co9 S8 /CoMoS and highest activity of DHS of DBT on the (1 1 0) facet-based catalyst. Enhanced MoS2 -CoMoS/MoS2 -Co9 S8 conjunction and synergism more efficient for the target reaction. Abstract: In this work, we studied how the oxidic CoMoO x /Al2 O3 and sulphurated CoMoS x /Al2 O3 interfacial structures determine catalytic efficiency in selective hydrodesulfurization (HDS) of dibenzothiophene (DBT). To achieve this goal, we first synthesized the γ-Al2 O3 materials of unique morphologies through the ionic liquid-assisted hydrothermal process under different conditions. The resulting γ-Al2 O3 hexagonal plates (HP) and stacked hexagonal plates (SHP) are single crystallites with the dominant (1 1 0) and (1 1 1)/(1 0 0) facet structures, respectively; whereas the Al2 O3 rods show polycrystalline feature. Through impregnation of Mo/Co salts of different loadings, the various CoMoO x precursors were generated on the different Al2 O3 facets owing to the distinct interaction: mostly the two-dimensional (2D) poly-/mono-meric MoO x species together with the three-dimensional (3D) MoO3 on the Al2 O3 (1 1 0) facet vs. the quasi 2D polymeric MoO x species on the Al2 O3 polycrystalline facet. Such structural difference further affected the sulfidation of the MoCoO x as well as the quantity of active MoCoS x entities on different γ-Al2 O3 supports: 10Mo3CoS x /Al2 O3 -HP had the highest level of MoCoO x sulfidation thus a much higher fraction of MoS2 plus Co9 S8 /CoMoS species whereas less quantity of partially sulphurated CoMoO x S2 /CoO x together with SO x 2- species. All the distinct interfacial domains of the sulphurated catalysts reasonably account for significantly different efficiency in HDS of DBT. Surface MoS2 /CoMoS/Co9 S8 species of the highest content over the Al2 O3 (1 1 0) facet correspond to the highest DBT areal conversion rate and TOF value, owing to the enhanced MoS2 -Co9 S8 and MoS2 -CoMoS conjunction and synergism.