scholarly journals Ru-Promoted Ni/Al2O3 Fluidized Catalyst for Biomass Gasification

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 316 ◽  
Author(s):  
Alan Rubén Calzada Hernandez ◽  
Daniel Gibran González Castañeda ◽  
Adriana Sánchez Enriquez ◽  
Hugo de Lasa ◽  
Benito Serrano Rosales
Keyword(s):  
Acid Site ◽  
Biomass Gasification ◽  
Temperature Programmed Desorption ◽  
Steam Gasification ◽  
Bet Surface Area ◽  
Temperature Programmed Reduction ◽  
N2 Adsorption ◽  
Site Density ◽  
Temperature Programmed ◽  
Adsorption Desorption

Fluidizable catalysts based on Ni/Al2O3 with added Ru were used for the gasification of a lignin surrogate (2-methoxy-4-methylphenol) in a fluidized CREC Riser Simulator reactor. This was done in order to quantify lignin surrogate conversion and lignin surrogate products (H2, CO, CO2 and CH4) as well as the coke deposited on the catalyst. The catalysts that were evaluated contained 5% wt. Ni with various Ru loadings (0.25%, 0.5% and 1% wt). These catalysts were synthesized using an incipient Ni and Ru co-impregnation. Catalysts were characterized using XRD, N2 adsorption-desorption (BET Surface Area, BJH), Temperature Programmed Reduction (TPR), Temperature Programmed Desorption (TPD) and H2 chemisorption. Catalytic steam gasification took place at 550, 600 and 650 °C using 0.5, 1.0 and 1.5, steam/biomass ratios. The results obtained showed that Ru addition helped to decrease both nickel crystallite site sizes and catalyst acid site density. Moreover, it was observed that coke on the catalyst was reduced by 60%. This was the case when compared to the runs with the Ni/Al2O3 free of Ru.

scholarly journals Composites of Laponite and Cu–Mn Hopcalite-Related Mixed Oxides Prepared from Inverse Microemulsions as Catalysts for Total Oxidation of Toluene

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1365 ◽  
Author(s):  
Bogna D. Napruszewska ◽  
Alicja Michalik ◽  
Anna Walczyk ◽  
Dorota Duraczyńska ◽  
Roman Dula ◽  
...  
Keyword(s):  
Mixed Oxide ◽  
Mixed Oxides ◽  
Active Phase ◽  
Temperature Programmed Reduction ◽  
Tetrabutylammonium Hydroxide ◽  
N2 Adsorption ◽  
Total Oxidation ◽  
Temperature Programmed ◽  
Adsorption Desorption ◽  
Mesoporous Structures

Composites of Laponite and Cu–Mn hopcalite-related mixed oxides, prepared from hydrotalcite-like (Htlc) precursors obtained in inverse microemulsions, were synthesized and characterized with XRF, XRD, SEM, TEM, H2 temperature-programmed reduction (TPR), and N2 adsorption/desorption at −196 °C. The Htlc precursors were precipitated either with NaOH or tetrabutylammonium hydroxide (TBAOH). Al was used as an element facilitating Htlc structure formation, and Ce and/or Zr were added as promoters. The composites calcined at 600 °C are mesoporous structures with similar textural characteristics. The copper–manganite spinel phases formed from the TBAOH-precipitated precursors are less crystalline and more susceptible to reduction than the counterparts obtained from the precursors synthesized with NaOH. The Cu–Mn-based composites are active in the combustion of toluene, and their performance improves further upon the addition of promoters in the following order: Ce < Zr < Zr + Ce. The composites whose active phases are prepared with TBAOH are more active than their counterparts obtained with the use of the precursors precipitated with NaOH, due to the better reducibility of the less crystalline mixed oxide active phase.

scholarly journals Catalytic Performance and Characterization of Ni-Co Bi-Metallic Catalysts in n-Decane Steam Reforming: Effects of Co Addition

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 518 ◽  
Author(s):  
Qinwei Yu ◽  
Yi Jiao ◽  
Weiqiang Wang ◽  
Yongmei Du ◽  
Chunying Li ◽  
...  
Keyword(s):  
Steam Reforming ◽  
Energy Dispersive Spectrometer ◽  
Coke Deposition ◽  
Morphological Properties ◽  
Temperature Programmed Reduction ◽  
N2 Adsorption ◽  
High Hydrogen ◽  
Hydrogen Selectivity ◽  
Temperature Programmed ◽  
Adsorption Desorption

Co-Ni bi-metallic catalysts supported on Ce-Al2O3 (CA) were prepared with different Co ratios, and the catalytic behaviors were assessed in the n-decane steam reforming reaction with the purpose of obtaining high H2 yield with lower inactivation by carbon deposition. Physicochemical characteristics studies, involving N2 adsorption-desorption, X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), NH3 temperature programmed reduction (NH3-TPD), SEM-energy dispersive spectrometer (EDS), and transmission electron microscope (TEM)/HRTEM, were performed to reveal the textural, structural and morphological properties of the catalysts. Activity test indicated that the addition of moderate Co can improve the hydrogen selectivity and anti-coking ability compared with the mono-Ni/Ce-Al2O3 contrast catalyst. In addition, 12% Co showed the best catalytic activity in the series Co-Ni/Ce-Al2O3 catalysts. The results of catalysts characterizations of XRD and N2 adsorption-desorption manifesting the metal-support interactions were significantly enhanced, and there was obvious synergistic effect between Ni and Co. Moreover, the introduction of 12% Co and 6% Ni did not exceed the monolayer saturation capacity of the Ce-Al2O3 support. Finally, 6 h stability test for the optimal catalyst 12%Co-Ni/Ce-Al2O3 demonstrated that the catalyst has good long-term stability to provide high hydrogen selectivity, as well as good resistance to coke deposition.

scholarly journals Nanosheet-Like Ho2O3 and Sr-Ho2O3 Catalysts for Oxidative Coupling of Methane

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 388
Author(s):  
Yuqiao Fan ◽  
Changxi Miao ◽  
Yinghong Yue ◽  
Weiming Hua ◽  
Zi Gao
Keyword(s):  
Oxidative Coupling ◽  
Temperature Programmed Desorption ◽  
Oxidative Coupling Of Methane ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Oxygen Species ◽  
N2 Adsorption ◽  
Basic Sites ◽  
Chemisorbed Oxygen ◽  
Temperature Programmed

In this work, Ho2O3 nanosheets were synthesized by a hydrothermal method. A series of Sr-modified Ho2O3 nanosheets (Sr-Ho2O3-NS) with a Sr/Ho molar ratio between 0.02 and 0.06 were prepared via an impregnation method. These catalysts were characterized by several techniques such as XRD, N2 adsorption, SEM, TEM, XPS, O2-TPD (temperature-programmed desorption), and CO2-TPD, and they were studied with respect to their performances in the oxidative coupling of methane (OCM). In contrast to Ho2O3 nanoparticles, Ho2O3 nanosheets display greater CH4 conversion and C2-C3 selectivity, which could be related to the preferentially exposed (222) facet on the surface of the latter catalyst. The incorporation of small amounts of Sr into Ho2O3 nanosheets leads to a higher ratio of (O− + O2−)/O2− as well as an enhanced amount of chemisorbed oxygen species and moderate basic sites, which in turn improves the OCM performance. The optimal catalytic behavior is achievable on the 0.04Sr-Ho2O3-NS catalyst with a Sr/Ho molar ratio of 0.04, which gives a 24.0% conversion of CH4 with 56.7% selectivity to C2-C3 at 650 °C. The C2-C3 yield is well correlated with the amount of moderate basic sites present on the catalysts.

scholarly journals Novel Nickel- and Magnesium-Modified Cenospheres as Catalysts for Dry Reforming of Methane at Moderate Temperatures

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1066 ◽  
Author(s):  
Bogdan Samojeden ◽  
Marta Kamienowska ◽  
Armando Izquierdo Colorado ◽  
Maria Elena Galvez ◽  
Ilona Kolebuk ◽  
...  
Keyword(s):  
Supported Catalysts ◽  
Temperature Programmed Desorption ◽  
Catalytic Performance ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Temperature Programmed Reduction ◽  
Fly Ashes ◽  
Coal Fly Ashes ◽  
Temperature Programmed ◽  
Mg Content

Cenospheres from coal fly ashes were used as support in the preparation of Ni–Mg catalysts for dry reforming of methane. These materials were characterized by means of XRD, H2-temperature-programmed reduction (H2-TPR), CO2-temperature-programmed desorption (CO2-TPD), and low-temperature nitrogen sorption techniques. The cenosphere-supported catalysts showed relatively high activity and good stability in the dry reforming of methane (DRM) at 700 °C. The catalytic performance of modified cenospheres was found to depend on both Ni and Mg content. The highest activity at 750 °C and 1 atm was observed for the catalyst containing 30 wt % Mg and 10, 20, and 30 wt % Ni, yielding to CO2 and CH4 conversions of around 95%.

Hydrogen Adsorption Capacity Investigation of Ni-Co-Al Mixed Oxides

2014 ◽  
Vol 917 ◽  
pp. 360-364 ◽  
Author(s):  
M. Abdus Salam ◽  
Suriati Sufian
Keyword(s):  
Hydrogen Adsorption ◽  
Mixed Oxides ◽  
Textural Properties ◽  
Metal Dispersion ◽  
Temperature Programmed Reduction ◽  
Oxide Formation ◽  
Nickel Cobalt ◽  
Icp Ms ◽  
Temperature Programmed ◽  
Adsorption Desorption

Micro-mesoporous mixed oxides containing nickel, cobalt and aluminum have been synthesized using conventional coprecipitation method. FESEM and HRTEM analyses demonstrated the flower and hexagonal plate-like nanostructured of mixed oxides. Different mixed oxide formation, homogenous metal dispersion, textural properties were investigated using XRD, ICP-MS and BET (N2 adsorption-desorption) techniques. nanostructured mixed oxides exhibited 2.6 wt% hydrogen adsorption that were studied using temperature programmed reduction-adsorption-desorption (H2-TPR/TPD) and thermogravimetric and differential thermal analysis (TGA-DTA) techniques. Investigation corresponds that morphologies, textural properties and surface energy of mixed oxides are important in hydrogen adsorption.

Promotion Effects of La2O3 on Ni/Al2O3 Catalysts for CO2 Methanation

2015 ◽  
Vol 1118 ◽  
pp. 205-210 ◽  
Author(s):  
Wei Chang Chen ◽  
Wen Yang ◽  
Jian Dong Xing ◽  
Lei Liu ◽  
Hong Li Sun ◽  
...  
Keyword(s):  
Particle Size ◽  
Impregnation Method ◽  
Temperature Programmed Reduction ◽  
Active Components ◽  
X Ray ◽  
Induce Effect ◽  
Temperature Programmed ◽  
Ni Species ◽  
Adsorption Desorption ◽  
Catalytic Performances

Ni/Al2O3catalysts improved with different La contents were prepared by the conventional co-impregnation method and characterized by X-ray powder diffraction (XRD), N2adsorption-desorption, H2temperature-programmed reduction (H2-TPR). Catalytic performances for CO2methanation under condition (CO2/H2=4.1:1, 1 atm) were discussed in detail. XRD result demonstrated that the addition of La was in favor of decreasing the Ni particle size and increasing the dispersion of Ni species. The H2-TPR showed that La can change the proportion of various Ni species and increase the content of easily reducible Ni species. These results indicate that La species induce effect, resulting in smaller particle size and weaker interaction between active components and the support, higher dispersions, and reducibility of active phases, ultimately improving catalytic activity of CO2methanation.

The Characterization of Hydrocarbon Intermediates in H-ZSM-5

1987 ◽  
Vol 111 ◽  
Author(s):  
T. J. Gricus Kofke ◽  
R. J. Gorte ◽  
W. E. Farneth
Keyword(s):  
Infrared Spectroscopy ◽  
Thermogravimetric Analysis ◽  
Acid Site ◽  
Adsorbed Molecule ◽  
Temperature Programmed Desorption ◽  
Acid Sites ◽  
Adsorption State ◽  
Brönsted Acid ◽  
Temperature Programmed

AbstractWe have examined the adsorption of simple alcohols and 2-propanamine on H-ZSM-5 zeolites with Si/Al2 ratios between 38 and 520. Thermogravimetric analysis (TGA) demonstrated that most of the molecules display a clearly defined adsorption state corresponding to a coverage of one molecule per Al site. Temperature programmed desorption (TPD) and transmission infrared spectroscopy results for each of the molecules in this 1:1 adsorption state are consistent with adsorption being due to the transfer of a proton from the zeolite to the adsorbed molecule. These results provide additional evidence that carefully prepared H-ZSM-5 is a Bronsted acid, with one acid site per framework Al atom, in which all of the acid sites are identical in strength.

Precursor chemistry of h-BN: adsorption, desorption, and decomposition of borazine on Pt(110)

2020 ◽  
Vol 22 (20) ◽  
pp. 11704-11712 ◽  
Author(s):  
Leander Haug ◽  
Jannik P. Roth ◽  
Marco Thaler ◽  
Dominik Steiner ◽  
Alexander Menzel ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Precursor Chemistry ◽  
Temperature Programmed Desorption ◽  
Photoemission Spectroscopy ◽  
Functional Theory ◽  
P Adsorption ◽  
Ultraviolet Photoemission Spectroscopy ◽  
Temperature Programmed ◽  
Adsorption Desorption

Adsorption, desorption and fragmentation of borazine on Pt(110) are studied by temperature-programmed desorption, ultraviolet photoemission spectroscopy, workfunction measurements and density functional theory.

Study of Preparation, Characterization and Temperature-Programmed Reduction of NiO-ZnO Binary Materials

2013 ◽  
Vol 664 ◽  
pp. 515-520
Author(s):  
Chih Wei Tang ◽  
Jiunn Jer Hwang ◽  
Shie Hsiung Lin ◽  
Chin Chun Chung
Keyword(s):  
Weight Percent ◽  
Precipitation Method ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Temperature Programmed ◽  
Co Precipitation ◽  
Adsorption Desorption

The NiO-ZnO binary materials had been prepared by co-precipitation method. The weight percent of nickel of NiO-ZnO materials were 5, 10 and 20; they were pretreated under air at temperature of 300, 500 and 700°C, respectively. The characterization of NiO-ZnO materials were the thermal gravity analysis(TGA), X-ray diffraction(XRD), N2 adsorption-desorption at 77K, scaning electron microscope(SEM) and temperature-programmed reduction(TPR). The results revealed that surface areas of NiO-ZnO materials order from large to small were 20NiZn(OH)x(66 m2·g-1) > 10NiZn(OH)x(34 m2·g-1) > 5NiZn(OH)x(9 m2·g-1) after being calcined at the temperature of 500°C. Further, NiO-ZnO materials had two main reductive peaks at 390-415°C and 560-657°C, respectively. In all NiO-ZnO materials, 20NiZn(OH)x-C500 material had the highest surface area and the best interaction between NiO and ZnO.

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