scholarly journals EFFECT OF PREPARATION METHOD OF Ni CATALYST USING BENTONITE AS THE SUPPORT MATERIAL

2010 ◽  
Vol 3 (2) ◽  
pp. 118-125
Author(s):  
Hery Haerudin ◽  
Silvester Tursiloadi ◽  
Galuh Widiyarti ◽  
Wuryaningsih Sri Rahayu
Keyword(s):  
Nickel Catalyst ◽  
Preparation Method ◽  
Nickel Content ◽  
Peak Position ◽  
Single Peak ◽  
Main Peak ◽  
Ni Catalyst ◽  
Support Material ◽  
Temperature Programmed Oxidation ◽  
Temperature Programmed

Nickel catalyst has been prepared impregnation and precipitation with nickel content of 20% and 25% each using bentonite as support material. The effects of the preparation method were studied using temperature programmed oxidation (TPO) and temperature programmed reduction (TPR) and by determination of its specific surface area. The activity of catalysts has been tested in the hydrogenation of palm oil. The catalyst with 20% of nickel and prepared by impregnation shows a single peak at 301°C, compared to catalyst with 25% of nickel prepared by the same method which has a peak at 304°C and a shoulder at 330°C. The reduction curves of both catalysts, those are prepared by impregnation, show a homogeneity indicated by a high main peak at 426°C (20% Ni) and 430°C (25% Ni). The 25% nickel catalyst by impregnation has a shoulder at 508°C. The catalysts prepared by precipitation show peaks at 508°C and 661°C for 20% of Ni and peaks at 419°C and 511°C for 25% of Ni. The reduction curves of catalysts prepared by precipitation are significantly different from each other. Those are also very different comparing to the reduction curve of impregnated catalyst. The 20% precipitated nickel catalyst has a single peak at 540°C, but the 25% precipitated nickel catalyst shows peaks at 346°C and 503°C. The differences of peak position among the reduction curves of catalysts resulted in the differences of catalyst activities with the following order 20% Ni (impregnation) > 25% Ni (impregnation) > 20% Ni (precipitation) > 25% Ni (precipitation).   Keywords: bentonite, nickel catalyst, hidrogenation

scholarly journals A Ni-based catalyst with polyvinyl pyrrolidone as a dispersant supported in a pretreated fluid catalytic cracking catalyst residue for C9 petroleum resin (C9 PR) hydrogenation

2018 ◽  
Vol 5 (5) ◽  
pp. 172052 ◽  
Author(s):  
Dong Chen ◽  
Linlin Wang ◽  
Xiaopeng Chen ◽  
Xiaojie Wei ◽  
Jiezhen Liang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Catalytic Cracking ◽  
Nickel Content ◽  
Fluid Catalytic Cracking ◽  
Polyvinyl Pyrrolidone ◽  
Ni Catalyst ◽  
Petroleum Resin ◽  
Temperature Programmed ◽  
Ni Species ◽  
Bromine Number

A Ni-based catalyst (Ni-PVP/PFC3R) with polyvinyl pyrrolidone (PVP) as a dispersant supported in a pretreated fluid catalytic cracking catalyst residue (PFC3R) was synthesized and applied to C9 petroleum resin (C9 PR) hydrogenation. For comparison, a Ni catalyst without PVP (Ni/PFC3R) was prepared in the same way. Ni-PVP/PFC3R exhibited higher activity and better stability. The catalysts were characterized by X-ray diffraction, scanning electron microscope, H 2 -temperature programmed reduction/temperature programmed desorption, Fourier transform infrared spectroscopy and the Brunauer–Emmett–Teller method. The catalysts had a smaller crystallite size and stronger interactions between the Ni species and the PFC3R support in the presence of PVP. The effects of nickel loading, H 2 pressure, temperature and reaction time for C9 PR hydrogenation over Ni-PVP/PFC3R were investigated. The bromine number was reduced to 1.25 under the following conditions: nickel content of 12 wt%, PVP amount of 1.5 wt%, temperature of 270°C, H 2 pressure of 8 MPa and reaction time of 240 min.

N2O Temperature-Programmed Oxidation and EXAFS Studies on the Dispersion of Copper in Ceria-Supported Nanocatalysts

2005 ◽  
Vol 17 (15) ◽  
pp. 3935-3943 ◽  
Author(s):  
A. Tschöpe ◽  
J. Markmann ◽  
P. Zimmer ◽  
R. Birringer ◽  
Chadwick
Keyword(s):  
Temperature Programmed Oxidation ◽  
Temperature Programmed

Isothermal and temperature-programmed oxidation of CH over Pt{}-(1×2)

2002 ◽  
Vol 505 ◽  
pp. 58-70 ◽  
Author(s):  
D.T.P. Watson ◽  
J.J.W. Harris ◽  
D.A. King
Keyword(s):  
Temperature Programmed Oxidation ◽  
Temperature Programmed

Surface Characterization of W/Ni/Al2O3 Catalysts

1997 ◽  
Vol 497 ◽  
Author(s):  
M. H. Jordão ◽  
J. M. Assaf ◽  
P. A. P. Nascente
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Surface Characterization ◽  
Nickel Content ◽  
Stable Phase ◽  
Preparation Methods ◽  
X Ray ◽  
Inductively Coupled ◽  
Temperature Programmed ◽  
Two Phases

ABSTRACTCatalysts containing tungsten and nickel oxides are important in hydrodesulfurization (HDS), hydrogénation (HY), and steam reforming of hydrocarbons. A series of W/Ni/Al2O3 catalysts was prepared by two different methods: (1) coprecipitation of nickel and aluminium hydroxicarbonate from their nitrates, followed by calcination and impregnation of tungsten; (2) precipitation of boehmite from aluminium nitrate, followed by impregnations of nickel, firstly, and tungsten. The nickel content was kept constant, while the amount of tungsten varied from 2.5 to 15.5 wt-%. The resulting oxides were characterized by inductively coupled plasma spectroscopy (ICP), atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). ICP and AAS were used to determine the W, Ni, and Al concentrations. XRD detected two phases: NiO and NiAl2O4 (no phase containing metallic tungsten was detected). Increasing the amount of W, the quantity of NiAl2O4 rose, the quantity of NiO decreased, and the particle size of NiO enlarged. The TPR profiles presented three peaks: one at about 1000 °C, associated to a very stable phase; for the samples prepared by coprecipitation, the other two peaks corresponded to “free NiO” and a nonstoichiometric aluminate. For the samples prepared by impregnation, those peaks corresponded to NiO and NiAl2O4. XPS identified Al2O3, NiAl2O4, and Al2(WO4)3 for both preparation methods. Increasing the amount of tungsten in the impregnated samples, NiWO4 was also observed.

Synthesis and characterizations of TiN–SBA-15 mesoporous materials for CO2 dry reforming enhancement

2020 ◽  
Vol 92 (4) ◽  
pp. 545-556
Author(s):  
Maslin Chotirach ◽  
Supawan Tantayanon ◽  
Duangamol Nuntasri Tungasmita ◽  
Junliang Sun ◽  
Sukkaneste Tungasmita
Keyword(s):  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
High Specific Surface Area ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Ni Catalyst ◽  
X Ray ◽  
Novel Approach ◽  
Temperature Programmed ◽  
Adsorption Desorption

AbstractA novel approach of titanium nitride (TiN) incorporated into SBA-15 framework was developed using one-step hydrothermal synthesis method. TiN contents up to ~18 wt% were directly dispersed in a synthetic gel under a typical strong acidic condition. The physico-chemical characteristics and the surface properties were investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), N2 adsorption-desorption, field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray spectroscopy (EDS), wavelength dispersive X-ray fluorescence (WDXRF) and CO2-temperature programmed desorption (CO2-TPD). The results indicated that the highly ordered mesostructured was effectively maintained with high specific surface area of 532–685 m2g−1. The basicity of the modified SBA-15 increased with rising TiN loading. These modified materials were applied as a support of Ni catalyst in dry reforming of methane (DRM). Their catalytic behavior possessed superior conversions for both CO2 and CH4 with the highest H2/CO ratio (0.83) as well as 50 % lower carbon formation, compared to bare SBA-15 support.

scholarly journals Hydrogenation and Hydrodeoxygenation of Oxygen-Substituted Aromatics over Rh/silica: Catechol, Resorcinol and Hydroquinone

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 584
Author(s):  
Kathleen Kirkwood ◽  
S. David Jackson
Keyword(s):  
Hydroxyl Group ◽  
Trans Isomers ◽  
Cumulative Yield ◽  
Temperature Programmed Oxidation ◽  
Kinetic Isotope ◽  
A Value ◽  
Negative Order ◽  
Temperature Programmed ◽  
Direct Hydrogenation ◽  
Positive Half

The hydrogenation and hydrodeoxygenation (HDO) of dihydroxybenzene isomers, catechol (1,2-dihydroxybenzene), resorcinol (1,3-dihydroxybenzene) and hydroquinone (1,4-dihydroxybenzene) was studied in the liquid phase over a Rh/silica catalyst at 303–343 K and 3 barg hydrogen pressure. The following order of reactivity, resorcinol > catechol > hydroquinone (meta > ortho > para) was obtained. Kinetic analysis revealed that catechol had a negative order of reaction whereas both hydroquinone and resorcinol gave positive half-order suggesting that catechol is more strongly adsorbed. Activation energies of ~30 kJ·mol−1 were determined for catechol and hydroquinone, while resorcinol gave a value of 41 kJ·mol−1. Resorcinol, and similarly hydroquinone, gave higher yields of the hydrogenolysis products (cyclohexanol, cyclohexanone and cyclohexane) with a cumulative yield of ~40%. In contrast catechol favoured hydrogenation, specifically to cis-1,2-dihydroxycyclohexane. It is proposed that cis-isomers are formed from hydrogenation of dihydroxycyclohexenes and high selectivity to cis-1,2-dihydroxycyclohexane can be explained by the enhanced stability of 1,2-dihydroxycyclohex-1-ene relative to other cyclohexene intermediates of catechol, resorcinol or hydroquinone. Trans-isomers are not formed by isomerisation of the equivalent cis-dihydroxycyclohexane but by direct hydrogenation of 2/3/4-hydroxycyclohexanone. The higher selectivity to HDO for resorcinol and hydroquinone may relate to the reactive surface cyclohexenes that have a C=C double bond β-γ to a hydroxyl group aiding hydrogenolysis. Using deuterium instead of hydrogen revealed that each isomer had a unique kinetic isotope effect and that HDO to cyclohexane was dramatically affected. The delay in the production of cyclohexane suggest that deuterium acted as an inhibitor and may have blocked the specific HDO site that results in cyclohexane formation. Carbon deposition was detected by temperature programmed oxidation (TPO) and revealed three surface species.

scholarly journals Nickel-Catalysed Vapour-Phase Hydrogenation of Furfural, Insights into Reactivity and Deactivation

2020 ◽  
Vol 63 (15-18) ◽  
pp. 1446-1462 ◽  
Author(s):  
Kathryn L. MacIntosh ◽  
Simon K. Beaumont
Keyword(s):  
Furfuryl Alcohol ◽  
Copper Chromite ◽  
Catalyst Support ◽  
Nickel Catalysts ◽  
Vapour Phase ◽  
X Ray Diffraction ◽  
Temperature Programmed Oxidation ◽  
Acidic Sites ◽  
Supported Nickel Catalysts ◽  
Temperature Programmed

AbstractFurfural is a key bioderived platform molecule, and its hydrogenation affords access to a number of important chemical intermediates that can act as “drop-in” replacements to those derived from crude oil or novel alternatives with desirable properties. Here, the vapour phase hydrogenation of furfural to furfuryl alcohol at 180 °C over standard impregnated nickel catalysts is reported and contrasted with the same reaction over copper chromite. Whilst the selectivity to furfuryl alcohol of the unmodified nickel catalysts is much lower than for copper chromite as expected, the activity of the nickel catalysts in the vapour phase is significantly higher, and the deactivation profile remarkably similar. In the case of the supported nickel catalysts, possible contribution to the deactivation by acidic sites on the catalyst support is discounted based on the similarity of deactivation kinetics on Ni/SiO2 with those seen for less acidic Ni/TiO2 and Ni/CeO2. Powder X-ray diffraction is used to exclude sintering as a primary deactivation pathway. Significant coking of the catalyst (~ 30 wt% over 16 h) is observed using temperature programmed oxidation. This, in combination with the solvent extraction analysis and infrared spectroscopy of the coked catalysts points to deactivation by polymeric condensation products of (reactant or) products and hydrocarbon like coke. These findings pave the way for targeted modification of nickel catalysts to use for this important biofeedstock-to-chemicals transformation.

scholarly journals Effect of Ionic Liquid Surfactants on Coal Oxidation and Structure

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Weiqing Zhang ◽  
Shuguang Jiang ◽  
Tong Qin ◽  
Jianfeng Sun ◽  
Chaowei Dong ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Critical Micelle Concentration ◽  
Ammonium Chloride ◽  
Coal Oxidation ◽  
Thermal Stabilities ◽  
Oxidation Activity ◽  
Temperature Programmed Oxidation ◽  
Surface Activities ◽  
Temperature Programmed

The effects of six ionic liquids with surfactant property (1-hydroxyethyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide ([HOEtMIm][NTf2]), 1-hydroxyethyl-3-methyl imidazolium tetrafluoroborate ([HOEtMIm][BF4]), 1-dodecyl-3- methyl imidazolium bromide ([C12MIm]Br), 1-tetradecyl-3- methyl imidazolium bromide ([C14MIm]Br), trioctyl methyl ammonium chloride ([N8,8,8,1])Cl, and tetraethyl ammonium chloride ([N2,2,2,2]Cl)) on the oxidation characteristics and functional groups of coal were studied by means of critical micelle concentration, surface tension, thermogravimetric analysis, temperature-programmed oxidation, and Fourier transform infrared spectroscopy (FTIR) measurements. The lower critical micelle concentration for the ionic liquids except the [N2,2,2,2]Cl suggests the favorable surface activity of these ionic liquids. The surface activities of [N8,8,8,1]Cl, [C14MIm]Br, [C12MIm]Br, and [HOEtMIm][NTf2] were high, while that of [N2,2,2,2]Cl was relatively lower. The thermal stabilities of [HOEtMIm][NTf2] and [HOEtMIm][BF4] were high, while those of [N8,8,8,1]Cl and [N2,2,2,2]Cl were lower. The oxidation activities of ionic liquid-mixed coals were weakened to different degrees except [N8,8,8,1]Cl-mixed coal, because of the poor thermal stability and decomposition of [N8,8,8,1]Cl accelerating the coal oxidation. The other five ionic liquids were suitable for inhibiting coal oxidation, particularly the [HOEtMIm][BF4] and [HOEtMIm][NTf2] with higher inhibition rate, longer inhibition time, and also better thermal stabilities. The activation energy results further confirmed such inhibition effect. The functional group results showed that treatment of ionic liquids on coal can change the contents of hydrogen bonds, aliphatic groups, and aromatic groups in coal. It was inferred that the [HOEtMIm][BF4], [HOEtMIm][NTf2], and [C14MIm]Br were more effectively to affect coal structure and decrease coal oxidation activity.

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