The effect of organic additives and phosphoric acid on sulfidation and activity of (Co)Mo/Al2O3 hydrodesulfurization catalysts

Haandel, L. van; Bremmer, G.M.; Hensen, Emiel J. M.; Weber, Th.

doi:10.1016/j.jcat.2017.04.012

Cited by 74 publications

(49 citation statements)

References 70 publications

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“…The catalysts prepared using glycols show a higher HDS activity than the catalyst prepared without the additive (Table 5). This is consistent with the results obtained in [6][7][8][9][10][11][12]. The HDS activity decreased in the following order: NiMoP-DEG/Al 2 O 3 > NiMoP-EG/Al 2 O 3 > NiMoP-TEG/Al 2 O 3 > NiMoP/Al 2 O 3 .…”

Section: Catalytic Activitysupporting

confidence: 91%

“…One of the recognized approaches to enhance the activity of HDS catalysts in the hydrotreating reactions is the addition of phosphoric acid to the impregnating solution [5][6][7][8]. Phosphate has a beneficial effect due to several factors, such as the increased solubility of the molybdenum salts, stability of the impregnation solution, and decreased metal-support interaction.…”

Section: Introductionmentioning

confidence: 99%

“…Depending on the reaction conditions, phosphoric acid reacts with the molybdenum precursor (ammonium heptamolybdate or MoO 3 ) and gives a variety of phosphomolybdate anions, such as diphosphopentamolybdate (P 2 Mo 5 O 23 6− ), Keggin (PMo 12 O 40 3− ), and Dawson (P 2 Mo 18 O 62 6− ) heteropolyanions (HPAs). Further, the use of various types of organic modifiers during catalyst preparation has resulted in materials of enhanced HDS activity; both chelating agents and glycol-type additives are used for this purpose [1, 3,4,[6][7][8][9][10][11][12]. In contrast with ligand-type modifiers, such as α-hydroxycarboxylic, thioglycolic, or aminopolycarboxylic acid, only a limited number of publications have been found concerning the effect of glycol-type additives on catalytic properties of sulfide CoMo or NiMo catalysts [3,13].…”

Section: Introductionmentioning

confidence: 99%

“…Most articles describe the effect of glycols on the activity of CoMo systems, using post-treatment of CoMo(P)/Al 2 O 3 systems with triethylene glycol (TEG) or polyethylene glycol (PEG) [14][15][16], or co-impregnation with the solution of active metals and glycols [6][7][8][9]17]. Just a few reports are found concerning the effect of addition of glycols to the impregnation solution on the activity of NiMo/Al 2 O 3 catalysts [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…Just a few reports are found concerning the effect of addition of glycols to the impregnation solution on the activity of NiMo/Al 2 O 3 catalysts [10][11][12]. It was shown that the glycol-modified catalysts displayed higher activity in the HDS of model compounds [6][7][8][9][10][11][12]16,17] and gasoil fractions [10,12,16,17], as well as in toluene hydrogenation [14,15]. Moreover, a synergetic effect of glycol-type additives and phosphate was disclosed [6,7,12].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Mono-, Di-, and Triethylene Glycol on the Activity of Phosphate-Doped NiMo/Al2O3 Hydrotreating Catalysts

et al. 2019

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The effect of glycols on the catalytic properties of phosphate-doped NiMo/Al2O3 catalysts in the hydrotreating of straight-run gas oil (SRGO) was studied. The NiMo(P)/Al2O3 catalysts were prepared using ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) as additives. The organic agent was introduced into the aqueous impregnation solution obtained by the dissolving of MoO3 in H3PO4 solution, followed by Ni(OH)2 addition. The Raman and UV–Vis studies show that the impregnation solution contains diphosphopentamolybdate HxP2Mo5O23(6−x)− and Ni(H2O)62+, and that these ions are not affected by the presence of glycols. When the impregnation solution comes in contact with the γ-Al2O3 surface, HxP2Mo5O23(6−x)− is decomposed completely. The catalysts were characterized by Raman spectroscopy, low-temperature N2 adsorption, X-ray photoelectron spectroscopy, and transmission electron microscopy. It is shown that the sulfide catalysts prepared with glycols display higher activity in the hydrotreating of straight-run gas oil than the NiMoP/Al2O3 catalyst prepared without the additive. The hydrodesulfurization and hydrodenitrogenation activities depend on the glycol type and are decreased in the following order: NiMoP-DEG/Al2O3 > NiMoP-EG/Al2O3 > NiMoP-TEG/Al2O3 > NiMoP/Al2O3. The higher activity of NiMoP-DEG/Al2O3 can be explained with the higher dispersion of molybdenum on the surface of the catalyst in the sulfide state.

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Section: Catalytic Activitysupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Mono-, Di-, and Triethylene Glycol on the Activity of Phosphate-Doped NiMo/Al2O3 Hydrotreating Catalysts

et al. 2019

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Role of Phosphorus and Triethylene Glycol Incorporation on the Activity of Model Alumina‐Supported CoMoS Hydrotreating Catalysts

et al. 2022

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Environmental regulations concerning fuel‐related sulfur emissions are currently experiencing worldwide expansion. This is motivating the research and development of improved hydrotreating (HDT) catalysts with carefully engineered synthesis methods that maximize activity as ultimate goal. In this contribution, the effect of phosphorus doping and triethylene glycol (TEG) incorporation on the genesis of the CoMoS phase of model HDT catalysts is assessed. Following a surface‐science approach, α‐Al2O3 single crystals with four orientations: C(0001), A(11true2‾ 0), M(10true1‾ 0), and R(1true1‾ 02) are used as model supports of the traditional γ‐Al2O3 support for the study of active phase‐support interactions at the molecular scale. The model catalysts are prepared by traditional impregnation of a solution containing metal and phosphorus precursors and TEG. The catalysts are characterized in the sulfide phase by XPS, XAS, TEM, and AFM, revealing that the calcination step is key in the emergence of distinctive metal‐support interactions, which are directly related to the nature of alumina surface sorption sites. In addition, TEG incorporation on dried catalysts increases metal sulfidation and enhances promotion with respect to non‐additivated systems, especially at mild sulfidation temperatures. The catalytic activity of the model catalysts is tested in a thiophene hydrodesulfurization reaction, revealing the following activity trend with respect to alumina surface orientations: A()112‾0 ≫ M()101‾0 >R()11‾02 , C(0001). This trend is identical to the one observed for non‐phosphorus doped non‐TEG additivated model systems, confirming the predominance of surface effects on the catalytic activity over those exerted by P and TEG. By transposing these results to the industrial γ‐Al2O3 support, the (100) facet would provide surface sites that lead to better performing catalysts. This could result in the development of novel supports, engineered to expose surface sites that maximize hydrotreating activity.

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Surface‐Dependent Activation of Model α‐Al₂O₃‐Supported P‐Doped Hydrotreating Catalysts Prepared by Spin Coating

Castro

Bertrand

Rigaud

et al. 2020

Chemistry A European J

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Requirements for improved catalytic formulations is continuously driving researchi nh ydrotreating (HDT)c atalysis for biomass upgrading and heteroatom removalf or cleanerf uels. The present work proposes as urface-science approach for the understanding of the genesis of the active (sulfide) phase in model P-doped MoS 2 hydrotreating catalysts supported on a-Al 2 O 3 single crystals. This approach allows one to obtain as urface-dependenti nsightb yv arying the crystal orientationso ft he support. Model phosphorusdoped catalysts are preparedv ia spin-coating of MoP precursor solutions onto four a-Al 2 O 3 crystalo rientations, C(0001), A(112 0), M(101 0) and R(11 02) that exhibit different speciations of surface-OH. 31 Pa nd 95 Mo liquid-state NMR are used to give ac omprehensive description of the Mo andP speciation of the phospho-molybdic precursor solution. The speciation of the deposition solution is then correlatedw ith the genesiso ft he active MoS 2 phase.X PS quantificationo f the surfaceP /Mo ratio reveal as urface-dependent phosphate aggregation driven by the amount of free phosphates in solution.P hosphates aggregation decreases in the following order C(0001) @ M(101 0) > A(112 0), R(11 02). This evolution can be rationalized by an increasing strength of phosphate/surface interactions on the different a-Al 2 O 3 surface orientations from the C(0001) to the R(11 02) plane. Retardation of the sulfidation with temperature is observed for model catalystsw ith the highest phosphate dispersion on the surface(A(112 0), R(11 02)), suggesting that phosphorus strongly intervene in the genesis of the activep hase through ac lose intimacy between phosphates and molybdates.T he surface P/Mo ratio appears as ak ey descriptor to quantify this retarding effect.I ti sp roposedt hat retardation of sulfidation is drivenb yt wo effects:i)achemicali nhibition through formation of hardly reducible mixed molybdo-phosphates tructures and ii)a physicali nhibition with phosphate clusters inhibiting the growth of MoS 2 .T he surface-dependent phosphorus dopingo nm odel a-Al 2 O 3 supportsc an be used as ag uide for the rational design of more efficient HDT catalysts on industrial g-Al 2 O 3 carrier.

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The effect of organic additives and phosphoric acid on sulfidation and activity of (Co)Mo/Al2O3 hydrodesulfurization catalysts

Cited by 74 publications

References 70 publications

Effect of Mono-, Di-, and Triethylene Glycol on the Activity of Phosphate-Doped NiMo/Al2O3 Hydrotreating Catalysts

Effect of Mono-, Di-, and Triethylene Glycol on the Activity of Phosphate-Doped NiMo/Al2O3 Hydrotreating Catalysts

Role of Phosphorus and Triethylene Glycol Incorporation on the Activity of Model Alumina‐Supported CoMoS Hydrotreating Catalysts

Surface‐Dependent Activation of Model α‐Al₂O₃‐Supported P‐Doped Hydrotreating Catalysts Prepared by Spin Coating

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The effect of organic additives and phosphoric acid on sulfidation and activity of (Co)Mo/Al2O3 hydrodesulfurization catalysts

Cited by 74 publications

References 70 publications

Effect of Mono-, Di-, and Triethylene Glycol on the Activity of Phosphate-Doped NiMo/Al2O3 Hydrotreating Catalysts

Effect of Mono-, Di-, and Triethylene Glycol on the Activity of Phosphate-Doped NiMo/Al2O3 Hydrotreating Catalysts

Role of Phosphorus and Triethylene Glycol Incorporation on the Activity of Model Alumina‐Supported CoMoS Hydrotreating Catalysts

Surface‐Dependent Activation of Model α‐Al2O3‐Supported P‐Doped Hydrotreating Catalysts Prepared by Spin Coating

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Surface‐Dependent Activation of Model α‐Al₂O₃‐Supported P‐Doped Hydrotreating Catalysts Prepared by Spin Coating