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A series of NiMo/FDU-12 catalysts with tunable pore diameters and mesostructures have been controllably synthesized by adjusting the synthetic hydrothermal temperature and applied for the hydrodesulfurization of dibenzothiophene and its derivative. The state-of-the-art electron tomography revealed that the pore sizes of FDU-12 supports were enlarged with the increase in the hydrothermal temperature and the mesostructures were transformed from ordered cage-type pores to locally disordered channels. Meanwhile, the MoS2 morphology altered from small straight bar to semibending arc to spherical shape and finally to larger straight bar with the change of support structures. Among them, FDU-12 hydrothermally treated at 150 °C possessed appropriate pore diameter and connected pore structure and was favorable for the formation of highly active MoS2 with curved morphology; thus, its corresponding catalyst exhibited the best HDS activity. Furthermore, it was indicated that the isomerization pathway could be significantly improved for HDS of 4,6-dimethyldibenzothiophene after the addition of aluminum, which was expected to be applied to the removal of the macromolecular sulfur compounds. Our study sheds lights on the relationship between support effect, active sites morphology and HDS performance, and also provides a guidance for the development of highly active HDS catalysts. [ABSTRACT FROM AUTHOR]

In this work, a series of Mo/γ-Al 2 O 3 catalysts have been prepared by using Mo species enwrapping with dodecyltrimethylammonium bromide (DTAB) as the novel precursors for the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The objective of this work is to get a deep insight into the effect of the Mo precursors on the size and morphology of the active phases and HDS activity. DTAB as the organic additive for the preparation of Mo precursors can dominate the nature of precursor solution and adjust the metal-support interaction so as to control the dispersion and morphology of the active phases. It is clearly shown that the addition of DTAB can effectively decrease the strong interaction between the Mo species and γ-Al 2 O 3 support and favor to tune the size and morphology of MoS 2 nanoparticles. The optimum molar ratio of DTAB/Mo is 3/5 and the corresponding catalyst shows the highest sulfidation degree with the most suitable stacking layer numbers and the shortest length of MoS 2 and thus exhibits the best HDS performance. Our work explores the important roles of organic additive to adjust the metal-support interaction and control the morphology of active phases and provides an effective precursor which can be used widely to prepare supported catalysts. [ABSTRACT FROM AUTHOR]

FDU-12 silica with highly ordered face-centered cubic mesoporous structure is developed as support to prepare Mo/FDU-12 catalysts for hydrodesulfurization (HDS) of dibenzothiophene (DBT). A series of Mo/FDU-12 catalysts are synthesized by using incipient wetness impregnation method with different MoO3 loadings (6, 8, 10, 12, and 15 wt.%). The objective of this work is to explore the pore confinement effect of FDU-12 mesochannels on the MoS2 morphology with various metal loadings. It is found that, as increasing MoO3 loadings from 6 to 15 wt.%, the MoS2 nanocrystallites transform from monolayer to multilayer and the morphology changes from straight layered to curved and then to ring-like and finally to spherical-like morphology due to the restriction of cage-like pore channels of FDU-12 support. The HDS results show that the catalytic activity increases first and then decreases with the best HDS performance at the MoO3 loading of 10 wt.%. In addition, we compared the HDS activity of Mo catalyst supported on FDU-12 with that on the commercial γ-Al2O3 and SBA-15; the result exhibits that FDU-12 is superior to the other two supports due to its large pore size and ordered three-dimensional open pore channels. [ABSTRACT FROM AUTHOR]

This article reports a novel method for preparing supported NiW hydrodesulfurization (HDS) catalysts with tunable size and morphology of active phases to achieve highly selective HDS performance in hydro-upgrading fluid catalytic cracking (FCC) naphtha. The proposed approach features the combined use of W-based hybrid nanocrystals (HNCs) as the W precursor and the promoting effect optimization of Ni promoter. The W-based HNCs synthesized under mild hydrothermal conditions are monodispersed particles with an average size of ca. 2 nm and show a core–shell structure with W 6 O 19 2− as the inorganic core and short-chain quaternary ammonium cations as the organic shell. The use of W-based HNCs facilitates the formation of highly dispersed W species and WS 2 active phases with enhanced stacking, thus yielding a larger number of accessible Ni–W–S edge sites upon nickel impregnation. Moreover, we found that the advantageous W dispersion in the HNC-derived monometallic catalyst precursor allows further modification of the size and morphology of the active phase via the optimized incorporation of Ni promoter, leading to the formation of Ni–W–S edge sites with a lower percentage of brim sites and thereby resulting in considerably higher selective HDS performance for FCC naphtha than its counterpart prepared by the conventional impregnation method. The proposed approach makes it easy to tune the size and morphology of WS 2 nanoparticles, shedding light on the rational design of supported WS 2 catalysts for FCC naphtha selective HDS. [ABSTRACT FROM AUTHOR]

Abstract: A series of mesoporous sieves with different pore diameters and structures have been controllably synthesized by adding variable amounts of swelling agent 1,3,5-trimethylbenzene in the preparation process for SBA-15. NiMo catalysts supported by mesoporous sieves are prepared by using the newly proposed Mo-based organic–inorganic hybrid nanocrystals as precursors to load Mo and subsequently using wetness impregnation to load Ni. The hydrodesulfurization (HDS) activity of these obtained catalysts is evaluated in a continuously flowing tubular fixed-bed microreactor using 1wt% dibenzothiophene (DBT) in heptane as a model compound. The results show that HDS ratio has gradually increased as the pore diameter of supports is enlarged from 7 to 11nm with the mesostructure keeping an ordered two-dimensional hexagonal symmetry. When the structure is in the intermediate stage of structural transition from ordered hexagonal mesostructure to mesocecullar structure, HDS ratio is decreased dramatically due to the disordered and collapsed structure to block the pore channels. After the mesocecullar structure with three-dimensional open pore channels is formed which is more convenient for the molecular diffusion, HDS ratio has increased again as a result. It is concluded that both the pore size and window size connecting the adjacent pores play an important role in the HDS activity but the window size is of more significant importance, which is the key point for the enhanced catalytic performance. [Copyright &y& Elsevier]

[Display omitted] • Ni 2 P/Al 2 O 3 with small nanoparticles and pure phase was controllably synthesized. • Ni 2 P/Al 2 O 3 shows excellent hydrogenation and desulfurization activities. • Nanoflower-like structure improves dispersion and accessibility of active sites. • The outstanding performance can be attributed to the rich Niδ+ active sites. The hydrogenation of unsaturated bonds and elimination of sulfur impurities in C 9 petroleum resin (C 9 PR) are crucial for improving its quality and performance. In this study, we prepared a nanoflower-like Ni 2 P/Al 2 O 3 catalyst using an in-situ synthesis combined with liquid-phase phosphidation strategy and applied for the production of value-added hydrogenated C 9 PR. In-situ synthesis of Ni-Al hydrotalcite anchors and disperses Ni nanoparticles, while liquid-phase phosphidation introduces high-content Niδ+ and Pδ− active sites and prevents the formation of inactive AlPO 4 , synergistically enhancing both hydrogenation and desulfurization activities. The synthesized Ni 2 P/Al 2 O 3 catalyst achieves a 99.6 % hydrogenation degree and reduces sulfur content from 137 ppm to 0 ppm, much better than the catalysts prepared by conventional impregnation and metal phosphate reduction methods. These results give valuable insights for designing efficient catalysts and advancing single-step hydrorefining processes to generate high-quality, value-added hydrogenated petroleum resins. [ABSTRACT FROM AUTHOR]

[Display omitted] • The flower-like nickel phosphide catalysts were prepared by a hydrotalcite strategy. • Ni 2 P/Al 2 O 3 catalyst showed excellent catalytic activity and desulfurization ability. • The outstanding performance ascribed to the rich active Niδ+ species. • The enhanced stability was due to strong interaction between active sites and support. The catalytic hydrogenation of petroleum resin (PR) to high value-added hydrogenated PR (HPR) represents a forward-looking technology for upgrading the pyrolysis petroleum by-product. Herein, flower-like and pure-phase supported nickel phosphide catalysts were controllably fabricated through a hydrotalcite strategy with red phosphorous as the P source. The PR hydrogenation activity of the catalysts followed the order of Ni 2 P/Al 2 O 3 > NiP 2 /Al 2 O 3 > Ni/Al 2 O 3 > imp-Ni 2 P/Al 2 O 3 catalysts (prepared by the impregnation method). Such enhanced performance of Ni 2 P/Al 2 O 3 could be ascribed to small nickel phosphide particle size and rich active Niδ+ species. Notably, the sulfur contents of PR were effectively reduced from 55.4 (C 5 PR) and 72.3 ppm (C 9 PR) to 3.8 and 7.9 ppm after hydrogenation by Ni 2 P/Al 2 O 3. Meanwhile, Ni 2 P/Al 2 O 3 also exhibited good stability with the hydrogenation degree of HC 5 PR maintaining at 94.39 % after 100 h. Our work provides a promising nickel phosphide catalyst with outstanding hydrogenation activity, hydrodesulfurization ability, and stability toward PR hydrogenation. [ABSTRACT FROM AUTHOR]