Hydrodesulfurization of dibenzothiophene, 4,6-dimethyldibenzothiophene, and their hydrogenated intermediates over bulk tungsten phosphide

Highly efficient hydrodesulfurization driven by an in-situ reconstruction of ammonium/amine intercalated MoS2 catalysts

Hydrodesulfurization (HDS) is a commonly used route for producing clean fuels in modern refinery. Herein, ammonium/amine-intercalated MoS2 catalysts with various content of 1T phase and S vacancies have been successfully synthesized. Along with the increment of 1T phase and S vacancies of MoS2, the initial reaction rate of the HDS of dibenzothiophene (DBT) can be improved from 0.09 to 0.55 μmol·gcat-1·s-1, accounting for a remarkable activity compared to the-state-of-the-art catalysts. In a combinatory study via the activity evaluation and catalysts characterization, we found that the intercalation species of MoS2 played a key role in generating more 1T phase and S vacancies through the 'intercalation-deintercalation' processes, and the hydrogenation and desulfurization of HDS can be significantly promoted by 1T phase and S vacancies on MoS2, respectively. This study provides a practically meaningful guidance for developing more advanced HDS catalysts by the intercalated MoS2-derived materials with an in-depth understanding of structure-function relationships.

HPW/PAM Catalyst for Oxidative Desulfurization-Synthesis, Characterization and Mechanism Study

In this work, polyacrylamide (PAM) was first used in the loading of heteropoly acids, and then the HPM/PAM-n catalyst was synthesized by simple reaction. The FTIR and SEM measurements showed that the HPM/PAM-n (n = 10,000, 20,000, 30,000) was successfully synthesized. In addition, the HPM/PAM-n effect on desulfurization was measured, which showed the optimal desulfurization efficiency. The optimal process condition for HPM/PAM-10000 desulfurization was optimized by a single-factor experiment. The optimal condition was as follows: The temperature was 60 °C, the amount of the catalyst was 0.2 g, the oxygen to sulfur ratio was 16, and the reaction time is 100 min. The catalyst was suitable for recycled use, and the desulfurization efficiency was high after 10 times. In the end, the oxidative desulfurization mechanism was put forward.

Constructing superior Co-Mo HDS catalyst from a crystalline precursor separated from the impregnating solution

In this paper, a Co tetra-capped Keggin crystalline Co4Mo12 was separated from the impregnating solution through the self-assembly strategy. The crystalline Co4Mo12 was structurally characterized and used as a molecular...

Sustainable development and enhancement of cracking processes using metallic composites

Metallic composites represent a vital class of materials that has gained increased attention in crude oil processing as well as the production of biofuel from other sources in recent times. Several catalytic materials have been reported in the literature for catalytic cracking, particularly, of crude oil. This review seeks to provide a comprehensive overview of existing and emerging methods/technologies such as metal–organic frameworks (MOFs), metal–matrix composites (MMCs), and catalytic support materials, to bridge information gaps toward sustainable advancement in catalysis for petrochemical processes. There is an increase in industrial and environmental concern emanating from the sulphur levels of oils, hence the need to develop more efficient catalysts in the hydrotreatment (HDS and HDN) processes, and combating the challenge of catalyst poisoning and deactivation; in a bid to improving the overall quality of oils and sustainable use of catalyst. Structural improvement, high thermal stability, enhanced cracking potential, and environmental sustainability represent the various benefits accrued to the use of metallic composites as opposed to conventional catalysts employed in catalytic cracking processes.

Structural Screening and Design of Dendritic Micro-Mesoporous Composites for Efficient Hydrodesulfurization of Dibenzothiophene and 4,6-Dimethyldibenzothiophene

Novel dendritic micro-mesoporous TS-1/dendritic mesoporous silica nanoparticle (DMSN) composites (TD) were assembled by TS-1 nanocrystals with ultrasmall particle size and strong acidity. TS-1 seeds and DMSNs were composited via the Ti-O-Si chemical bond, which stimulate the generation of Brønsted (B) and Lewis (L) acids. The spillover d-electrons produced by the Ti element of TS-1 seeds produced a spillover of d-electrons, which could interact with the surface of MoS₂ phases, thereby reducing Mo-S interactions and create sulfur vacancies that are favorable for dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) hydrodesulfurization (HDS) reactions. The increased amount of B&L acid of NiMo/TD-2.0 with cetyltrimethylammonium bromide/sodium salicylate molar ratio of 2.0 played an important role in facilitating the hydrogenation (HYD) route of DBT HDS and the isomerization (ISO) route of 4,6-DMDBT HDS, which is more favorable for the reduction of steric hindrance of DBT and 4,6-DMDBT reactants in the HDS reaction process. The NiMo/TD-2.0 catalyst exhibited the highest turnover frequency (TOF) value and HDS reaction rate constant (k_HDS) of DBT and 4,6-DMDBT due to its ultrasmall particle size, uniform spherical dendritic morphology, strong B&L acidity, and good stacking degree.

The effect of neodymium and yttrium on benzofuran hydrodeoxygenation performance over a bulk Ni2P catalyst

Neodymium (Nd)- or yttrium (Y)- modified bulk Ni2P catalysts (Nd-Ni2P or Y-Ni2P) have been successfully prepared and their catalytic performance in benzofuran hydrodeoxygenation have been investigated. The as-prepared catalysts were characterised by X-ray diffraction, N2 adsorption–desorption, CO uptake and X-ray photoelectron spectroscopy. The addition of Nd or Y, especially Nd, can increase the surface area of the catalysts and promote the formation of smaller and more highly dispersed Ni2P particles. The Nd-Ni2P catalyst showed the highest benzofuran hydrodeoxygenation activity of 95.3% and the O-free products yield of 74.6%, which gives an increase of 25.3% and 35.4% when compared with that found for Ni2P.

Room temperature oxidative desulfurization with MoO3 subnanoclusters supported on MCM-41

Subnano MoO₃/MCM-41 was successfully prepared through doping (NH₄)₆Mo₇O₂₄ in the synthesis process of MCM-41. The morphology of MoO₃/MCM-41 was visually observed by TEM and HADDF-STEM. N₂ sorption, XPS and Raman were further applied to investigate the structure of the material. MoO₃/MCM-41 was used in the oxidative desulfurization process with tert-butyl hydroperoxide as oxidant. MoO₃/MCM-41 showed outstanding catalytic activity and recycling ability at room temperature.

MoO₃ subnanoclusters encapsulated in MCM-41 exhibited enhanced catalytic activity and stability for oxidative desulfurization at room temperature.

A new approach to construct a hydrodesulfurization catalyst from a crystalline precursor: ligand-induced self-assembly, sulfidation and hydrodesulfurization

This paper proposes a new approach for investigating the mechanism of the formation of the active phase of a hydrodesulfurization (HDS) catalyst via crystalline polyoxometalate (POM) precursors.

Synthesis of ZSM-5/KIT-6 with a tunable pore structure and its catalytic application in the hydrodesulfurization of dibenzothiophene and diesel oil

Porous support materials were prepared by assembling primary and secondary ZSM-5 structural units into a well-ordered mesoporous framework. The materials possessed both ZSM-5 microporous building units and mesoporous structure were used as supports for the preparation of hydrodesulfurization (HDS) catalysts. The materials and their corresponding catalysts were characterized by XRD, FTIR, ²⁷Al MAS NMR, TEM, N₂ adsorption–desorption, Py-FTIR, H₂-TPR, Raman, and HRTEM techniques. The pore structures of the composite materials were modulated by adjusting the molar ratio of butanol/P123 (BuOH/P123) and then, the influences of BuOH/P123 on the catalytic performance in the HDS of dibenzothiophene (DBT) and diesel oil were systematically studied. The results showed that butanol has a big influence on the structure of the micro–mesoporous material, whereby different micro–mesoporous structures, such as the p6mm hexagonal structure or Ia3̄d cubic structure, were formed with different butanol addition amounts. The composite ZK-3 (BuOH/P123 = 100) possessed the best surface area and pore structure. Therefore, the NiMo/ZK-3 catalyst showed the highest catalytic activity in the HDS of DBT with a BP selectivity of 72.1% due to its excellent textural property, moderate MSI, relatively high B/L ratios, and highly dispersed NiMoS active phases. Moreover, the NiMo/AZK-3 catalyst exhibited excellent catalytic performance in the HDS of diesel oil.

Porous material with tunable pore structure ZSM-5/KIT-6 was prepared by adjusting the addition amount of n-butanol. NiMo/ZK-3 and NiMo/AZK-3 catalysts exhibit good catalytic performances in the HDS of DBT and diesel oil, respectively.

A size-matched POM@MOF composite catalyst for highly efficient and recyclable ultra-deep oxidative fuel desulfurization

A composite of Keggin-type phosphotungstic acid (H₃PW₁₂O₄₀) encapsulated in sized-matched metal–organic framework UiO-67 (PW₁₂@UiO-67) was prepared as a heterogeneous catalyst for extractive and catalytic oxidative desulfurization systems (ECODS).

Ultra-deep oxidative desulfurization of fuel with H2O2catalyzed by molybdenum oxide supported on alumina modified by Ca2+

A highly active catalyst of molybdenum oxide supported on mesoporous alumina modified by Ca²⁺was synthesized by anin situmethod and applied in the catalytic oxidative desulfurization (CODS) system.

Hydrodeoxygenation of gamma-valerolactone on transition metal phosphide catalysts

The catalytic hydrodeoxygenation (HDO) of the cyclic five-membered ester gamma-valerolactone (GVL-C₅H₈O₂) on a series of supported metal phosphide catalysts and a commercial Pd/Al₂O₃ catalyst was studied at 0.5 MPa.

Efficient hydrogenation performance improvement of MoP and Ni2P catalysts by adjusting the electron distribution around Mo and Ni atoms

The catalyst (MoP) was modified by higher electronegativity element W and lower electronegativity element Cu, realizing the control of hydrogenation performance of the catalysts.