The study on supported Fe and FeMo hydrotreating catalysts by combining Mössbauer spectroscopy and ordinary γ-ray transmission

Ramselaar, W. L. T. M.; Crajé, M.W.J.; Gerkema, E.; Hadders, R.H.; Loef, J.J. van; Beer, V.H.J. de; Kraan, A.M. van der

doi:10.1007/bf02400486

Cited by 8 publications

(2 citation statements)

References 3 publications

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“…Similar conclusions were obtained from research on alumina-supported TMS . Meanwhile, several research groups studied the promoter effect of Fe on the HDS activity of MoS 2 , , and a FeMoS phase, − which has a structure similar to that of the CoMoS phase, was proposed to be responsible for the weak synergetic effect of the FeMo catalyst. Other combinations such as FeW, FeV, and FeNi were also explored; it was found that Fe could incorporate easily with the above secondary metals, leading to the formation of Fe x W y C/N and pentlandite species and improving the dispersion of V active sites.…”

Section: Introductionsupporting

confidence: 70%

Promotion of the Inactive Iron Sulfide to an Efficient Hydrodesulfurization Catalyst

Liu

et al. 2017

ACS Catal.

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Extensive efforts have been devoted to developing desulfurization catalysts to effectively remove sulfur from fuel. Active phase metals including cobalt, nickel, molybdenum, and tungsten have been extensively used in industry for hydrotreating/hydrodesulfurization catalysts for over 50 years. However, while it is desirable to use inexpensive materials to do the same job, it is a grand challenge. Herein, we report a Fe-based sulfide catalyst that is tuned by zinc with high activity for HDS, which shows an industrial application potential to replace industrial Mo-based catalysts. With an optimal configuration that has a Fe:Zn ratio close to 1:1, the reaction rate constants of the dibenzothiophene (DBT) and 4,6-dimethydibenzothiophene (4,6-DMDBT) HDS are increased by 9.2 and 17.4 times, respectively, in comparison with the sums of those on the monoiron and zinc sulfides. HDS activity for the sterically hindered 4,6-DMDBT on the FeZn sulfide catalyst is even close to that of Co-MoS2. The experimental results indicate that the addition of Zn greatly modifies the electronic properties of iron sulfide by transferring electrons from Zn to Fe, which tunes the d band center to modulate the adsorption behavior of DBT and 4,6-DMDBT. In combination with theoretical calculations, our experiments show that the addition of Zn dramatically tunes the formation of sulfur vacancies. We propose that the formation of sulfur vacancies is the critical factor for designing highly efficient Fe-based sulfide catalysts. This study provides the design principle of low-cost desulfurization catalysts for industrial refinery applications.

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Section: Introductionsupporting

confidence: 70%

Promotion of the Inactive Iron Sulfide to an Efficient Hydrodesulfurization Catalyst

Liu

et al. 2017

ACS Catal.

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“…Instead of Mo- and W-based catalysts, some scholars paid more attention to Fe-based catalysts due to the abundant reserve, low cost, and environmental sustainability. While others introduced Mo, Ni, or V onto the Fe-based catalyst to further improve the HDS activity, a synergistic effect between Fe and these metal species on the HDS process was observed. − However, few studies focused on Fe-based catalysts, an active phase for the HDS process, due to their inherent low activity. Although it had been widely considered that the Fe-based catalysts exhibited poor HDS performance in the past few years, the addition of the Zn element would significantly enhance the HDS activity, which was reported in our previous study .…”

Section: Introductionmentioning

confidence: 99%

Tuning Effect of the Zeolite Brønsted Acidity on the FeZn Bimetallic Hydrodesulfurization Catalyst

et al. 2021

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The promotion of hydrodesulfurization (HDS) activity of supported Fe catalysts by regulation of the Brønsted (B) acid sites on supports has not been extensively investigated. In this paper, a Y-type zeolite-doped γ-Al2O3 support having different SiO2/Al2O3 ratios was utilized to demonstrate the influence of B acid sites on the catalytic activity of supported FeZn catalysts in HDS. It was found that an appropriate density of Brønsted acid sites could prompt not only the dispersion of active metal species but also the activity in HDS of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). Besides, the presence of an appropriate B acid site density could reduce the interaction between the support and active metal sites, decrease the reduction temperature of the metal oxide in the catalyst, and thus favor the sulfidation of as-prepared catalysts. In addition, the catalyst having B acid sites could facilitate the product selectivity through direct desulfurization (DDS) and isomerization (ISO) routes during HDS of DBT (or 4,6-DMDBT).

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Better sulphide catalysts through optimized active phase-support interaction

Moulijn

Doorn

Langeveld

et al. 1994

Int. J. Energy Res.

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In this project, improved hydrotreating catalysts have been synthesized by varying the active phase‐support interaction. This interaction has been changed by differing the calcining procedures and choice of catalyst precursors and carriers. The active phase consisted basically of molybdenum or tungsten disulphide, and Ni, Co, Cr or Fe as the promoter. Also phosphorus has been added as secondary promoter. As for the preparation of the catalysts, a new type of carrier, filamentary carbon supported by alumina, has been synthesized. To improve the interaction between Co and Mo in the active catalyst, nitrilotriacetic acid (NTA) has been added as a complexing agent to a solution containing both metal salts. Also, a new type of active phase precursor (acetylacetonate) has been used with a number of solvents (water, ethanol, toluene). The final consequences of these variations have been investigated from a physico‐chemical point of view in relation to the actual performance of the newly prepared catalysts in the hydrodesulphurization of thiophene. In the physico‐chemical characterization of the catalysts, Mössbauer emission and absorption spectroscopy (MES, MAS), X‐ray photoelectron spectroscopy (XPS), extended X‐ray absorption fine structure spectroscopy (EXAFS) and X‐ray absorption near edge structure (XANES) have been used. As a result, a detailed model of the so‐called ‘Co‐Mo‐S’ phase could be proposed. Mössbauer experiments on the sulphidation of carbon‐supported Co and Co‐Mo catalysts indicate the formation of Co species (consisting of Co and Co‐Mo, respectively), which have the same spectral features in Mössbauer spectroscopy. Hence, care should be taken into account when referring to the so called ‘Co‐Mo‐S’ phase. In addition, fingerprinting techniques such as TPR (temperature programmed reduction) and TPS (temperature programmed sulphidation) have been applied extensively. The sulphided catalysts contain different sulphur species. The existence of a very reactive sulphur species called ‘excess sulfur’ is correlated with the hydrodesulphurization activity. A model has been developed describing the coke deposition on hydrotreating catalysts under commercial reaction conditions. As a result, improved hydrotreating catalysts have been developed and a better understanding of the fundamental characteristics of the catalysts has been acquired. Novel equipment has been developed. Two of its major features are a simple design and the possibility for the in situ measurement of physical parameters of the autoclave contents. For future development of the catalysts, a detailed kinetic analysis of their performance, and the application of in situ characterization techniques is of paramount importance.

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The study on supported Fe and FeMo hydrotreating catalysts by combining Mössbauer spectroscopy and ordinary γ-ray transmission

Cited by 8 publications

References 3 publications

Promotion of the Inactive Iron Sulfide to an Efficient Hydrodesulfurization Catalyst

Promotion of the Inactive Iron Sulfide to an Efficient Hydrodesulfurization Catalyst

Tuning Effect of the Zeolite Brønsted Acidity on the FeZn Bimetallic Hydrodesulfurization Catalyst

Better sulphide catalysts through optimized active phase-support interaction

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