Effect of nickel on the surface acidity of γ-alumina and alumina-supported nickel—molybdenum hydrotreating catalysts

Stanislaus, A.; Absi‐Halabi, M.; Al-Dolama, K.

doi:10.1016/s0166-9834(00)80839-8

Cited by 25 publications

(22 citation statements)

References 23 publications

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“…In Cr doped catalysts, acid sites of medium strength were more abundant (56%) whereas for the nickel doped catalyst, higher concentration of strong acid sites were observed (53%). This is in agreement with the result obtained by Stanislaus et al [14] for alumina supported nickel catalyst. For the doped catalysts, with an increase in M/V ratio, the total area under the curves increased, reflecting the increase in total acidity.…”

Section: Resultssupporting

confidence: 94%

Oxidative dehydrogenation of propane over chromium and nickel oxide modified V2O5/ZrO2 catalysts

Kunzru

2007

React Kinet Catal Lett

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The effect of addition of chromium and nickel oxides on the physicochemical properties and performance of V 2 O 5 /ZrO 2 catalysts was studied for the oxidative dehydrogenation of propane. Addition of chromium oxide increased, whereas addition of nickel oxide lowered the activity. Selectivity for propene was lower for the doped catalysts. The selectivity was lowered by higher total acidity as well as the higher concentration of stronger acid sites in doped catalysts.

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Section: Resultssupporting

confidence: 94%

Oxidative dehydrogenation of propane over chromium and nickel oxide modified V2O5/ZrO2 catalysts

Kunzru

2007

React Kinet Catal Lett

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“…Therefore, this hydrothermal treatmentinduced change of the silica surface is expected to influence the macro properties of the silica. 19 After the hydrothermally treated silica was functionalized by 3-APTES, signals of the isolated hydroxyl groups at 1.8 ppm and geminal hydroxyl groups at 2.1 ppm almost disappeared, as shown in Figure 3(c). However, the signal observed at 3.1 ppm for the hydroxyl groups hydrogenbonded with water in the hydrothermally treated silica was shifted to 3.5 ppm and exhibited an increased intensity.…”

Section: Resultsmentioning

confidence: 93%

Multinuclear Solid-state NMR Investigation of Nanoporous Silica Prepared by Sol-gel Polymerization Using Sodium Silicate

Kim¹,

Han²,

Kim³

2011

Bulletin of the Korean Chemical Society

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Multinuclear solid-state nuclear magnetic resonance (NMR) experiments were performed to investigate the local structure changes of nanoporous silica during hydrothermal treatment and surface modification with 3-aminopropyltriethoxysilane (3-APTES). The nanoporous silica was prepared by sol-gel polymerization using inexpensive sodium silicate as a silica precursor. Using 1 H magic angle spinning (MAS) NMR spectra, the hydroxyl groups, which play an important role in surface reactions, were probed. Various silicon sites such as Q 2 , Q 3 , Q 4 , T 2 , and T 3 were identified with 29 Si cross polarization (CP) MAS NMR spectra and quantified with 29Si MAS NMR spectra. The results indicated that about 25% of the silica surface was modified. 1 H and 29 Si NMR data proved that the hydrothermal treatment induced dehydration and dehyroxylation. The 13 C CP MAS and 1 H MAS NMR spectra of 3-APTES attached on the surface of nanoporous silica revealed that the amines of the 3-aminopropyl groups were in the chemical state of NH 3 + rather than NH 2 .

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“…Barrio et al [21] found that Ni addition to acidic silica-alumina decreased its acidity to 59% its original value with 4% Ni and to 65% with 8% Ni, while the original strong acid sites disappeared, being neutralized and converted to weak and mildly strong ones. The formation of surface nickel aluminates and its effect in increasing the net positive charge of the surface coordinatively unsaturated sites has been proposed in order to rationalize the influence of nickel on increasing the acid strength of amphoterous g-alumina [22]. Rodrı´guez-Castello´n et al [23] have found that Ni addition to SiO 2 -ZrO 2 decreases the total acidity from to 53% its original value with 15% Ni and to 86% for 30% Ni.…”

Section: Resultsmentioning

confidence: 99%

Comparison between Ni and Pt promoted SO42??ZrO2 catalysts for n-octane hydroisomerization-cracking

et al. 2005

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The production of C 4 -C 6 branched isoalkanes by isomerization-cracking of n-octane (300°C, 0.1 MPa) using sulfated zirconia catalysts was studied. The effect of Ni addition on the activity and selectivity was compared to the effect of Pt. Pt enhanced the activity and stability of the catalysts. Ni mainly improved the selectivity to isoparaffins (maximum yield at 1% Ni). n-Octane conversion fully correlated with total acidity. Average and final stable conversion values were in comparison lower for Ni catalysts. This result was addressed to the lower metal activity of Ni and to the detrimental effect of sulfated zirconia on the reducibility of the metal.

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Effect of nickel on the surface acidity of γ-alumina and alumina-supported nickel—molybdenum hydrotreating catalysts

Cited by 25 publications

References 23 publications

Oxidative dehydrogenation of propane over chromium and nickel oxide modified V2O5/ZrO2 catalysts

Oxidative dehydrogenation of propane over chromium and nickel oxide modified V2O5/ZrO2 catalysts

Multinuclear Solid-state NMR Investigation of Nanoporous Silica Prepared by Sol-gel Polymerization Using Sodium Silicate

Comparison between Ni and Pt promoted SO42??ZrO2 catalysts for n-octane hydroisomerization-cracking

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