The effect of silanol groups on the metal-support interactions in silica-supported cobalt Fischer-Tropsch catalysts. A temperature programmed surface reaction

Okoye-Chine, Chike George; Mbuya, Christel O.L.; Ntelane, Tau S.; Moyo, Mahluli; Hildebrandt, Diane

doi:10.1016/j.jcat.2019.10.036

Cited by 32 publications

(18 citation statements)

References 44 publications

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“…Generally, the reduction temperature of the active sites in the catalyst is positively correlated with their metal particle size and metal− support interaction. 20,29,30 According to our former TEM and XRD results, the C-Ni/Al-SiO 2 and P-Ni/Al-SiO 2 catalysts show much smaller Ni NPs than N-Ni/Al-SiO2 (4.2−4.5 vs 20.0 nm). Therefore, both catalysts show a H 2 reduction profile with multioverlapped peaks from 330 to 600 °C.…”

Section: Resultsmentioning

confidence: 86%

Effect of Pore Structures on 1,4-Butynediol Hydrogenation over Mesoporous Ni/Al₂O₃-SiO₂ Catalysts

Wang

Jiang

Bai

et al. 2021

Ind. Eng. Chem. Res.

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This work describes the 1,4-butynediol (BYD) hydrogenation to 1,4-butanediol (BDO) performance over supported Ni/Al2O3-SiO2 catalysts with different mesoporous structures (cross pore C-Ni/Al-SiO2, parallel pore P-Ni/Al-SiO2, and nonmesoporous structured N-Ni/Al-SiO2). To illustrate the pore structure effects on the catalyst texture, metal–support interaction, and surface acidity, the obtained catalysts were characterized using BET, inductively coupled plasma (ICP), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2 temperature-programed reduction (H2-TPR), and H2/NH3-temperature-programmed desorption (H2/NH3-TPD). Based on this, we proposed the structure–activity relationship between the pore structures and the hydrogenation performance. It was found that C-Ni/Al-SiO2 had short-range staggered and cross mesopores throughout the support, which can provide a larger surface area and pore volume for the fixation of highly dispersed active sites, thus enhancing the H2 activation ability. On the other hand, the cross channels have rich hole loops and surface defects for exposing assistant acid sites that are beneficial for the 1,4-butynediol (BYD) adsorption/activation, thus promising a superior hydrogenation ability. However, the narrow and long parallel pore structure of P-Ni/Al-SiO2 may limit the rapid diffusion of long-carbon-chain BYD in the pores, thus partially decreasing the accessibility of active sites and the catalytic activity. As for N-Ni/Al-SiO2, which has no mesoporous structure, its nickel particles are prone to aggregate seriously on the support surface, which weakens the interaction with the support and is not conducive to catalytic hydrogenation.

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Section: Resultsmentioning

confidence: 86%

Effect of Pore Structures on 1,4-Butynediol Hydrogenation over Mesoporous Ni/Al₂O₃-SiO₂ Catalysts

Wang

Jiang

Bai

et al. 2021

Ind. Eng. Chem. Res.

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“…For 15Co/CoAl 2 O 4 , the temperatures of the two CH 4 desorption peaks were 429.4 and 452.2 K, respectively. The activation energy (Ea) values required for CH 4 formation over the four catalysts were calculated by Redhead’s equation , and are listed in Table . It was seen that the Ea values for CH 4 formation at T1 for 15Co/CoAl 2 O 4 , 15Co/Al 2 O 3 , and 15Co/MgAl 2 O 4 were close to each other, which were lower than that of 15Co/ZnAl 2 O 4 .…”

Section: Resultsmentioning

confidence: 99%

“…CO was adsorbed on the surface of the catalysts and then heated under a flow of 10% H 2 /Ar mixture. The signal of m/e = 16 was detected by MS to record the content of CH 4 vs temperature and is shown in 44,45 and are listed in Table 4.…”

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confidence: 99%

Co–Al Spinel as an Efficient Support for Co-Based Fischer–Tropsch Catalyst: The Effect of Metal–Support Interaction

Zhao

Lyu

et al. 2021

Ind. Eng. Chem. Res.

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Suitable metal–support interaction is of great significance for the supported Fischer–Tropsch catalyst. Herein, we synthesized a series of porous spinel MAl2O4 (M = Co, Mg, Zn) together with Al2O3, via a sol–gel method and used them as supports for the Co-based Fischer–Tropsch synthesis (FTS) catalyst to investigate the influence of metal–support interaction on Co dispersity, reducibility, and catalytic performance. The catalytic performance showed that 15Co/CoAl2O4 had the highest activity and C5+ selectivity, as well as favorable stability during 1000 h lifetime testing. The catalysts were characterized by physisorption, chemisorption, HRTEM, XPS, and TPSR. The results indicated that 15Co/CoAl2O4 showed weaker metal–support interaction than 15Co/MgAl2O4 and 15Co/Al2O3, which was considered as the key factor for its higher reducibility and CO dissociation ability, contributing to the higher CO conversion. The higher Co dispersity on CoAl2O4 resulted from the smaller particle size of Co species on CoAl2O4, contributing to the higher activity of 15Co/CoAl2O4 than that of 15Co/ZnAl2O4. The higher C5+ selectivity on 15Co/CoAl2O4 and 15Co/ZnAl2O4 than that on 15Co/MgAl2O4 and 15Co/Al2O3 was verified to benefit from the appropriate H2/CO adsorption ability, which was significantly affected by metal–support interaction.

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“…In Figure 4 , the peak appearing at about 2978 cm −1 is attributed to the –CH 3 groups for TEOS and MTES. The absorption peak located at 1640 cm −1 is associated with the stretching and bending vibration of –OH groups [ 42 ] from the absorbed water and ethanol as well as Si–OH. Undoubtedly, the existence of 1276 cm −1 band indicates the stretching vibration of the Si–CH 3 groups.…”

Section: Resultsmentioning

confidence: 99%

Sol-Gel Processed Cobalt-Doped Methylated Silica Membranes Calcined under N2 Atmosphere: Microstructure and Hydrogen Perm-Selectivity

Wang

Yang

et al. 2021

Materials

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Methyl-modified, cobalt-doped silica (Co/MSiO2) materials were synthesized by sol-gel technique calcined in N2 atmospheres, and membranes were made thereof by coating method. The effects of Co/Si molar ratio (nCo) on the physical-chemical constructions of Co/MSiO2 materials and microstructures of Co/MSiO2 membranes were systematically investigated. The gas permeance performance and hydrothermal stability of Co/MSiO2 membranes were also tested. The results show that the cobalt element in Co/MSiO2 material calcined at 400 °C exists not only as Si–O–Co bond but also as Co3O4 and CoO crystals. The introduction of metallic cobalt and methyl can enlarge the total pore volume and average pore size of the SiO2 membrane. The activation energy (Ea) values of H2, CO2, and N2 for Co/MSiO2 membranes are less than those for MSiO2 membranes. When operating at a pressure difference of 0.2 MPa and 200 °C compared with MSiO2 membrane, the permeances of H2, CO2, and N2 for Co/MSiO2 membrane with nCo = 0.08 increased by 1.17, 0.70, and 0.83 times, respectively, and the perm-selectivities of H2/CO2 and H2/N2 increased by 27.66% and 18.53%, respectively. After being steamed and thermally regenerated, the change of H2 permeance and H2 perm-selectivities for Co/MSiO2 membrane is much smaller than those for MSiO2 membrane.

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The effect of silanol groups on the metal-support interactions in silica-supported cobalt Fischer-Tropsch catalysts. A temperature programmed surface reaction

Cited by 32 publications

References 44 publications

Effect of Pore Structures on 1,4-Butynediol Hydrogenation over Mesoporous Ni/Al₂O₃-SiO₂ Catalysts

Effect of Pore Structures on 1,4-Butynediol Hydrogenation over Mesoporous Ni/Al₂O₃-SiO₂ Catalysts

Co–Al Spinel as an Efficient Support for Co-Based Fischer–Tropsch Catalyst: The Effect of Metal–Support Interaction

Sol-Gel Processed Cobalt-Doped Methylated Silica Membranes Calcined under N2 Atmosphere: Microstructure and Hydrogen Perm-Selectivity

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The effect of silanol groups on the metal-support interactions in silica-supported cobalt Fischer-Tropsch catalysts. A temperature programmed surface reaction

Cited by 32 publications

References 44 publications

Effect of Pore Structures on 1,4-Butynediol Hydrogenation over Mesoporous Ni/Al2O3-SiO2 Catalysts

Effect of Pore Structures on 1,4-Butynediol Hydrogenation over Mesoporous Ni/Al2O3-SiO2 Catalysts

Co–Al Spinel as an Efficient Support for Co-Based Fischer–Tropsch Catalyst: The Effect of Metal–Support Interaction

Sol-Gel Processed Cobalt-Doped Methylated Silica Membranes Calcined under N2 Atmosphere: Microstructure and Hydrogen Perm-Selectivity

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Effect of Pore Structures on 1,4-Butynediol Hydrogenation over Mesoporous Ni/Al₂O₃-SiO₂ Catalysts

Effect of Pore Structures on 1,4-Butynediol Hydrogenation over Mesoporous Ni/Al₂O₃-SiO₂ Catalysts