The effect of boron on the state and dispersion of Co/Al2O3 catalysts

Stranick, Michael; Houalla, Marwan; Hercules, David M.

doi:10.1016/0021-9517(87)90372-1

Cited by 73 publications

(22 citation statements)

References 23 publications

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“…The Al(2p) peak is observed in all spectra, and the measured binding energies (73.7-74.0 eV) are in the expected range for γ-Al 2 O 3 . [24] The B(1s) peak grows in intensity with increasing B loading and its binding energy (192.2-192.5 eV) is close to the value for interfacial aluminum borate (9Al 2 O 3 • 2B 2 O 3 ) of 192.5 eV, [25] which is below the binding energy of bulk B 2 O 3 (193.5 eV [25] ), and nearly identical to values reported for a B 2 O 3 surface layer on γ-Al 2 O 3 . [21,[25][26][27] The B(1s)/Al(2p) peak area ratio increases linearly with increasing B loading up to~4.7 wt % B, beyond which the peak area ratio increases more slowly.…”

Section: Characterization Of Xbà Al 2 O 3 Supportsmentioning

confidence: 67%

“…[24] The B(1s) peak grows in intensity with increasing B loading and its binding energy (192.2-192.5 eV) is close to the value for interfacial aluminum borate (9Al 2 O 3 • 2B 2 O 3 ) of 192.5 eV, [25] which is below the binding energy of bulk B 2 O 3 (193.5 eV [25] ), and nearly identical to values reported for a B 2 O 3 surface layer on γ-Al 2 O 3 . [21,[25][26][27] The B(1s)/Al(2p) peak area ratio increases linearly with increasing B loading up to~4.7 wt % B, beyond which the peak area ratio increases more slowly. These results are consistent with previous XPS studies, [21,[25][26] and indicate the growth of well dispersed B 2 O 3 species on the γ-Al 2 O 3 support up to monolayer coverage.…”

Section: Characterization Of Xbà Al 2 O 3 Supportsmentioning

confidence: 73%

“…[21,[25][26][27] The B(1s)/Al(2p) peak area ratio increases linearly with increasing B loading up to~4.7 wt % B, beyond which the peak area ratio increases more slowly. These results are consistent with previous XPS studies, [21,[25][26] and indicate the growth of well dispersed B 2 O 3 species on the γ-Al 2 O 3 support up to monolayer coverage. A calculation of the theoretical monolayer coverage using a B 2 O 3 cross-sectional area of (0.17 nm 2 /molecule [28] ) yields a loading of 4.3 wt % B (see Supporting Information), which is in good agreement with the value determined by XPS.…”

Section: Characterization Of Xbà Al 2 O 3 Supportsmentioning

confidence: 99%

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Hydrodesulfurization Properties of Nickel Phosphide on Boron‐treated Alumina Supports

et al. 2020

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The deep hydrodesulfurization (HDS) properties of nickel phosphide (Ni 2 P) on boron-modified alumina (xBÀ Al 2 O 3) supports having different B contents have been investigated. Ni 2 P precursors were prepared on the xBÀ Al 2 O 3 supports using hypophosphite (-hypo) or phosphate (-phos) as the P source and were subsequently reduced in flowing hydrogen. The 4,6dimethyldibenzothiophene HDS activities and turnover frequencies of the Ni 2 P/xBÀ Al 2 O 3 catalysts showed a strong dependence on B loading, with a maximum observed for the hypophosphite-and phosphate-based Ni 2 P/BÀ Al 2 O 3 catalysts corresponding to 0.8 wt % and 1.2 wt % B loadings, respectively. Based on XPS and IR spectral measurements, the optimal B loadings corresponded to~20 % B 2 O 3 coverage of the γ-Al 2 O 3 support and coincided with removal of the most basic hydroxyl groups on the alumina surface. At 573 K, a Ni 2 P/0.8BÀ Al 2 O 3-hypo catalyst was 2.5 times more active than a B-free Ni 2 P/Al 2 O 3-hypo catalyst, while a Ni 2 P/1.2BÀ Al 2 O 3-phos catalyst was 8.6 times more active than a B-free Ni 2 P/Al 2 O 3-phos catalyst. Overall, the hypophosphite-based Ni 2 P/BÀ Al 2 O 3 catalysts exhibited higher HDS activities than the phosphate-based Ni 2 P/BÀ Al 2 O 3 catalysts, in part due to smaller Ni 2 P particle sizes. The optimized catalysts, Ni 2 P/0.8BÀ Al 2 O 3-hypo and Ni 2 P/1.2BÀ Al 2 O 3-phos , were more active than a sulfided NiÀ Mo/Al 2 O 3 catalyst.

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Section: Characterization Of Xbà Al 2 O 3 Supportsmentioning

confidence: 67%

Section: Characterization Of Xbà Al 2 O 3 Supportsmentioning

confidence: 73%

Section: Characterization Of Xbà Al 2 O 3 Supportsmentioning

confidence: 99%

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Hydrodesulfurization Properties of Nickel Phosphide on Boron‐treated Alumina Supports

et al. 2020

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“…S3(d) in the Supplementary Material], the addition of SiO 2 produces a decrease of the triplet with maxima at 540, 580, and 630 nm associated with cobalt tetrahedrally coordinated. 32,33 For CoMoSAC, a significant increase in the absorption bands at 450 and 750 nm associated with octahedral Co species (Co Oh ) is observed. The results in Table II column 7 show that the Co Oh (750 nm)/Co Td (580 nm) ratio is considerably higher for the CoMoSAC catalyst.…”

Section: Uv-vis-drsmentioning

confidence: 99%

Relevant changes in the properties of Co(Ni)Mo/Al₂O₃HDS catalysts modified by small amounts of SiO₂

et al. 2018

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The changes in hydrodesulfurization activity, selectivity, dispersion, sulfidation, and extent of promotion of Co(Ni)Mo catalysts were investigated when the alumina support surface is modified by grafting 4 wt% silica. Adding SiO 2 eliminates the most reactive hydroxyl groups on the alumina surface (IR band at 3775 cm À1 ) decreasing the possibility of generating tetrahedral Mo species difficult to sulfide in favor of octahedral ones capable of contributing to the sulfided active phase. The catalysts were evaluated in the hydrodesulfurization of 4,6-dimethyldibenzothiophene. Incorporating SiO 2 to alumina increases the hydrogenation rate constant and therefore the global hydrodesulfurization rate of 4,6-dimethyldibenzothiophene and enhances the promotion of Mo by Co (or Ni). The global sulfidation of Ni is not affected by the addition of silica but the sulfidation of cobalt is significantly improved. The extent of promotion of the NiMo/Al 2 O 3 and NiMo/SiO 2 / Al 2 O 3 catalysts was greater than the one achieved in their Co-promoted counterparts.

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“…The incorporation of boron mainly affects acidity (Kwak et al, 2000;Lewandowski and Sarbak, 2000;Flego and O'Neil Parker, 1999;Lewis et al, 1989) and metal dispersion (Li et al, 1997;Ramirez et al, 1995;Sarbak and Andersson, 1991). Stranick et al (1987) believed that the addition of boron to -Al 2 O 3 could improve the dispersion of Co and change the chemical states of Co in Co/ -Al 2 O 3 catalysts. Li et al (1993) showed that the HDS activities of atmospheric gas oil (AGO) over Co-Mo/aluminum borate catalysts will be improved significantly compared to the conventional Co-Mo/ -Al 2 O 3 catalysts (Li et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

The Effect of Boron on the Activity of Hydrotreating Co-Mo/Al₂O₃Catalyst

Mohamed

Kady

Shaban

2013

Energy Sources, Part A: Recovery, Utilization, and Environmenta

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A series of aluminum borate with various boria content were prepared. These materials were used as the supports of Co-Mo catalysts. They were characterized with respect to surface area, pore volume, and pore size distribution. The temperature programmed reduction method was used to monitor molybdenum oxide-support interaction. The results showed that the addition of boria concentration (2, 4, and 6 wt%) decreases the reducibility of the catalyst, reduction peak increase with increasing B 2 O 3 content. Hydrodesulfurization of atmospheric gas oil was carried out over these presulfided catalysts in a bench-scale cata-test unit at 320-360 ı C and LHSV from 1 to 3 h 1 . Hydrogen pressure and H 2 /HC feed ratio were kept constant at 4 MPa and 300 l/l, respectively. All Co-Mo-/AB catalysts are much more active than the conventional Co-Mo/Al 2 O 3 catalyst on hydrodesulfurization reactions. The dispersion of the active sulfide phase of Co-Mo/Al 2 O 3 catalyst is increased by the incorporation of adequate boria content. An optimum B 2 O 3 content, which gives the highest activity, was found in the vicinity of 4 wt%.

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The effect of boron on the state and dispersion of Co/Al2O3 catalysts

Cited by 73 publications

References 23 publications

Hydrodesulfurization Properties of Nickel Phosphide on Boron‐treated Alumina Supports

Hydrodesulfurization Properties of Nickel Phosphide on Boron‐treated Alumina Supports

Relevant changes in the properties of Co(Ni)Mo/Al₂O₃HDS catalysts modified by small amounts of SiO₂

The Effect of Boron on the Activity of Hydrotreating Co-Mo/Al₂O₃Catalyst

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The effect of boron on the state and dispersion of Co/Al2O3 catalysts

Cited by 73 publications

References 23 publications

Hydrodesulfurization Properties of Nickel Phosphide on Boron‐treated Alumina Supports

Hydrodesulfurization Properties of Nickel Phosphide on Boron‐treated Alumina Supports

Relevant changes in the properties of Co(Ni)Mo/Al2O3HDS catalysts modified by small amounts of SiO2

The Effect of Boron on the Activity of Hydrotreating Co-Mo/Al2O3Catalyst

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Relevant changes in the properties of Co(Ni)Mo/Al₂O₃HDS catalysts modified by small amounts of SiO₂

The Effect of Boron on the Activity of Hydrotreating Co-Mo/Al₂O₃Catalyst