Influence of reduction temperature on the formation of intermetallic Pd 2 Ga phase and its catalytic activity in CO 2 hydrogenation to methanol

2019 ◽  
Vol 9 (3) ◽  
pp. 529-538 ◽  
Author(s):  
Kaisar Ahmad ◽  
Sreedevi Upadhyayula
Keyword(s):  
Catalytic Activity ◽  
Reduction Temperature

scholarly journals Influence of the Reduction Temperature and the Nature of the Support on the Performance of Zirconia and Alumina-Supported Pt Catalysts for n-Dodecane Hydroisomerization

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 88
Author(s):  
Diana García-Pérez ◽  
Maria Consuelo Alvarez-Galvan ◽  
Jose M. Campos-Martin ◽  
Jose L. G. Fierro
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Major Influence ◽  
Pt Catalysts ◽  
Reduction Temperature ◽  
Metal Dispersion ◽  
Tungsten Oxides ◽  
Supported Pt Catalysts

Catalysts based on zirconia- and alumina-supported tungsten oxides (15 wt % W) with a small loading of platinum (0.3 wt % Pt) were selected to study the influence of the reduction temperature and the nature of the support on the hydroisomerization of n-dodecane. The reduction temperature has a major influence on metal dispersion, which impacts the catalytic activity. In addition, alumina and zirconia supports show different catalytic properties (mainly acid site strength and surface area), which play an important role in the conversion. The NH3-TPD profiles indicate that the acidity in alumina-based catalysts is clearly higher than that in their zirconia counterparts; this acidity can be attributed to a stronger interaction of the WOx species with alumina. The PtW/Al catalyst was found to exhibit the best catalytic performance for the hydroisomerization of n-dodecane based on its higher acidity, which was ascribed to its larger surface area relative to that of its zirconia counterparts. The selectivity for different hydrocarbons (C7–10, C11 and i-C12) was very similar for all the catalysts studied, with branched C12 hydrocarbons being the main products obtained (~80%). The temperature of 350 °C was clearly the best reduction temperature for all the catalysts studied in a trickled-bed-mode reactor.

scholarly journals Improvement of Methane Combustion Activity for Pd/ZrO2 Catalyst by Simple Reduction/Reoxidation Treatment

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 838 ◽  
Author(s):  
Chansong Kim ◽  
Eunpyo Hong ◽  
Chae-Ho Shin
Keyword(s):  
Catalytic Activity ◽  
Low Temperatures ◽  
Methane Combustion ◽  
Reduction Temperature ◽  
Isothermal Reaction ◽  
Ch4 Combustion ◽  
Cyclic Temperature ◽  
Zro2 Catalyst ◽  
Number Of Cycles ◽  
Simple Reduction

The improvement of methane combustion activity was observed in cyclic temperature-programed and isothermal reactions over Pd/ZrO2 catalysts by simple reduction/reoxidation treatment. The catalytic activity increased during the initial stages of isothermal reaction, and the light-off temperature was lowered as the number of cycles increased in the cyclic temperature-programed reaction. To reveal the origin of activation, variations in the reduction properties after the activation period were carefully investigated through CH4 temperature-programed reduction (TPR) measurements. From the CH4-TPR results, it was confirmed that the reduction temperature decreased significantly after activation. The observation of the CH4-TPR peak at relatively low temperatures is directly proportional to the catalytic activity of CH4 combustion. It was therefore concluded that repeated reduction/reoxidation occurred in the reactant stream, and this phenomenon allowed the combustion reaction to proceed more easily at lower temperatures.

Ce0.70La0.20Ni0.10O2-δ catalyst for methane dry reforming: Influence of reduction temperature on the catalytic activity and stability

2017 ◽  
Vol 218 ◽  
pp. 779-792 ◽  
Author(s):  
Lidia Pino ◽  
Cristina Italiano ◽  
Antonio Vita ◽  
Massimo Laganà ◽  
Vincenzo Recupero
Keyword(s):  
Catalytic Activity ◽  
Dry Reforming ◽  
Reduction Temperature ◽  
Methane Dry Reforming

CO and CO2 Methanation Over Ni/γ-Al2O3 Prepared by Deposition-Precipitation Method

2019 ◽  
Vol 19 (6) ◽  
pp. 3252-3262 ◽  
Author(s):  
Thien An Le ◽  
Jong Kyu Kang ◽  
Sae Ha Lee ◽  
Eun Duck Park
Keyword(s):  
Catalytic Activity ◽  
Inductively Coupled Plasma ◽  
Precipitation Method ◽  
Active Surface Area ◽  
High Catalytic Activity ◽  
Reduction Degree ◽  
Reduction Temperature ◽  
Co2 Methanation ◽  
Selective Co Methanation ◽  
Ni Oxide

Various Ni catalysts supported on γ-Al2O3 were prepared by a wet impregnation (WI) method and deposition-precipitation (DP) method with different precipitants and applied to CO and CO2 methanation. The prepared catalysts were characterized by various techniques including nitrogen physisorption, X-ray diffraction (XRD), temperature-programmed reduction with H2 (H2-TPR), H2 chemisorption, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Irrespective of kinds of precipitant, the Ni/γ-Al2O3 catalysts prepared with a DP method showed a remarkable enhanced catalytic performance in CO and CO2 methanation compared with the Ni/γ-Al2O3 catalyst prepared with a WI method owing to the higher catalytic active surface area (CASA). In the case of Ni/γ-Al2O3 catalysts prepared with a DP method, the high calcination temperatures are not favorable for the high catalytic activity due to the decreased reduction degree of Ni oxide species and CASA. The reduction degree of Ni oxide species can be increased with reduction temperature. However, the higher reduction temperature above 500 °C is not desirable to achieve the high catalytic activity because of the decreased CASA. The selective CO methanation was also accomplished at lower temperatures over the Ni/γ-Al2O3 catalyst prepared with a DP method than over the Ni/γ-Al2O3 catalyst prepared with a WI method.

Catalytic Activity of Dehydrogenation of Methanol to MF over Cu/SBA-15 and Cu-ZnO/SBA-15 Prepared by Grinding and Impregnation

2012 ◽  
Vol 608-609 ◽  
pp. 1476-1479
Author(s):  
Min Jian Huang ◽  
Gong Li ◽  
Guo Ru Li
Keyword(s):  
Catalytic Activity ◽  
Molecular Sieve ◽  
Conversion Rate ◽  
Methyl Formate ◽  
Nitrogen Adsorption ◽  
Methanol Conversion ◽  
Reduction Temperature ◽  
Catalytic Activities ◽  
Adsorption Desorption

Using SBA-15 molecular sieve as the support, Cu/SBA-15 and Cu-ZnO/SBA-15 catalysts were prepared by grinding and impregnation. They were characterized by XRD, TEM, TPR and nitrogen adsorption/desorption methods. Their catalytic activities of the dehydrogenation of methanol to methyl formate (MF) were studied and compared.The results indicated that the Cu and ZnO in the catalysts prepared by grinding had a worse dispersity than that prepared by impregnation. However, the reduction temperature of the CuO in the catalysts prepared by grinding was obviously lower than that prepared by impregnation and the selectivity to MF can be improved with the adding of ZnO. The experiments showed that the methanol conversion rate and selectivity to MF were 15.23% and 79.81% at 270°C for Cu-ZnO/SBA-15-G prepared by grinding, respectively. For Cu-ZnO/SBA-15-I prepared by impregnation, the methanol conversion rate and selectivity to MF were 13.41 % and 81.31% respectively.

scholarly journals Efficient non-noble Ni–Cu based catalysts for the valorization of palmitic acid through a decarboxylation reaction

2021 ◽  
Author(s):  
Camila P. Ferraz ◽  
Anouchka Kiméné ◽  
Karen Silva Vargas ◽  
Svetlana Heyte ◽  
Claire Durlin ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Synergistic Effect ◽  
Palmitic Acid ◽  
Bimetallic Catalyst ◽  
Reduction Temperature ◽  
Decarboxylation Reaction ◽  
The Stability

The synergistic effect Ni–Cu in the bimetallic catalyst Ni–Cu/C improved the stability and reduction temperature as well as enhanced the catalytic activity for the decarboxylation of palmitic acid.

scholarly journals Enhancing the Activity and Stability of CuO/OMS-2 Catalyst for CO Oxidation at Low Temperature by Modification with Metal Oxides

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Nhat Huy Nguyen ◽  
Bich Thao Nguyen Thi ◽  
Thao Giang Nguyen Le ◽  
Quynh Anh Nguyen Thi ◽  
Phuoc Toan Phan ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Co Oxidation ◽  
Mixed Oxides ◽  
Specific Rate ◽  
Reduction Temperature ◽  
Low Temperature Oxidation ◽  
Octahedral Structure ◽  
Temperature Oxidation ◽  
Surface Oxides

In this study, mixed oxides of Mn-Cu and Fe-Cu on OMS-2 support having an octahedral structure were synthesized by the refluxing and impregnation methods. The characteristics of the materials were analyzed by XRD, FTIR, SEM, EDX, and H2-TPR. In the CO oxidation test, CuFeOx/OMS-2 had slightly higher catalytic activity but is significantly more stable than CuMnOx/OMS-2 and CuO/OMS-2. Due to its lower reduction temperature in H2-TPR analysis, the Mars-Van-Krevelen mechanism for CuFeOx/OMS-2 (Cu2+–O–Fe3+ ↔ Cu+–□–Fe2+) could take place more energetically than CuO/OMS-2 and CuMnOx/OMS-2 (Cu2+–O2−–Mn4+ ↔ Cu+–□–Mn3+). In addition, the interaction between Fe and Cu in the catalyst could improve the durability of the surface oxides structure in comparison with that between Mn and Cu. With the high specific rate and TOF of 28.6 mmol/h.g and 0.508, respectively, CuFeOx/OMS-2 has a great potential as an effective catalyst for low-temperature oxidation application in CO and possible VOCs removal.

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