scholarly journals One-Step Fabrication of PtSn/γ-Al2O3 Catalysts with La Post-Modification for Propane Dehydrogenation

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1042
Author(s):  
Guangjian Wang ◽  
Kai Lu ◽  
Chaoqun Yin ◽  
Fanfei Meng ◽  
Qinqin Zhang ◽  
...  
Keyword(s):  
Textural Properties ◽  
Temperature Programmed Desorption ◽  
Catalytic Performance ◽  
Carbon Accumulation ◽  
Propane Dehydrogenation ◽  
Catalytic Dehydrogenation ◽  
Step Method ◽  
One Step ◽  
Temperature Programmed ◽  
Post Modification

The catalytic dehydrogenation of propane to propene is an alternative technique to supplement the traditional steam cracking and catalytic cracking process for satisfying the continuously increasing demand for propylene downstream products. In this study, the parent PtSn/γ-Al2O3 catalyst was fabricated via the one-step method for the subsequent La post-modification to prepare the catalysts for propane dehydrogenation. The prepared and spent catalysts were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, scanning electron microscope (SEM), NH3 temperature-programmed desorption (NH3-TPD), H2 temperature-programmed desorption (H2-TPR), and thermogravimetric (TG) analysis. The catalytic performance and characterization results demonstrated that the addition of La into the parent catalyst could significantly improve the catalytic performance of the prepared catalyst. Especially, the PtSn-La2.2 catalyst with the 2.2 wt.% La addition exhibited the stable and highest propylene selectivity (>84%) under the investigation time of 800 min. The introduced La exhibits the ability to adjust the textural properties of the obtained catalysts, curb the acidity of support, promote the reduction of Pt species, and reduce the carbon accumulation on the prepared 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%.

Hierarchical flower-like Bi2WO6 hollow microspheres: facile synthesis and excellent catalytic performance

RSC Advances ◽  
2015 ◽  
Vol 5 (29) ◽  
pp. 23080-23085 ◽  
Author(s):  
Peigen Zhang ◽  
Jian Zhang ◽  
Anjian Xie ◽  
Shikuo Li ◽  
Jiming Song ◽  
...  
Keyword(s):  
Hollow Spheres ◽  
Catalytic Performance ◽  
Hollow Microspheres ◽  
Solvothermal Process ◽  
Facile Synthesis ◽  
Step Method ◽  
Bismuth Tungstate ◽  
One Step ◽  
Excellent Catalytic Performance

A one step method has been developed for the fabrication of hierarchical flower-like bismuth tungstate (Bi2WO6) hollow spheres via a solvothermal process.

One-Step FSP Synthesis of Nanocrystalline Fe/Al2O3 and Fe-Ce/Al2O3 Catalyst for CO2 Hydrogenation Reaction

2018 ◽  
Vol 916 ◽  
pp. 134-138 ◽  
Author(s):  
Kanyarat Piriyasurawong ◽  
Sunthon Piticharoenphun ◽  
Okorn Mekasuwandumrong
Keyword(s):  
Catalytic Activity ◽  
Iron Oxide ◽  
Catalytic Performance ◽  
Hydrogenation Reaction ◽  
Flame Spray ◽  
One Step ◽  
Temperature Programmed ◽  
The One ◽  
Long Chain ◽  
Chain Hydrocarbon

Nanocrystalline Fe/Al2O3and Fe-Ce/Al2O3catalysts doped with various amounts of cerium were prepared using the one-step flame spray pyrolysis (FSP) technique. The characterization of the catalysts was measured by several methods such as X-ray diffraction, nitrogen physisorption and hydrogen temperature programmed reduction (H2-TPR) techniques. The results revealed that the FSP-made catalyst exhibited the characteristic pattern of FeAl2O4phase without any phases of aluminum or iron oxide. In addition, cerium (Ce) dopant did not alter crystal structure at low content. However, 7 wt% content of cerium dopant resulted in the formation of ceria (CeO) and iron oxide (Fe2O3) phase. The catalytic performance of the FSP-made catalyst was tested in carbon dioxide hydrogenation for selective production of long chain hydrocarbon, and was compared to conventional impregnation-made catalysts. In the comparison, the FSP-made catalyst exhibited lower catalytic activity but possessed a higher long chain hydrocarbon selectivity. After doping with Ce, the catalytic activity was improved while the hydrocarbon selectivity was decreased and shifted to the short chain hydrocarbon product. In the case of conventional-made catalysts, the activity remained unchanged but the hydrocarbon selectivity was decreased. Among all catalysts, the FSP-made Fe-Ce/Al2O3catalyst with 3% Ce-promoted catalyst exhibited the best performance in terms of selectivity to long chain hydrocarbon.

scholarly journals Morphological Control of Carbon-Supported Pt-Based Nanoparticles via One-Step Synthesis

2019 ◽  
Author(s):  
Tatsuichiro Nakamoto
Keyword(s):  
Catalytic Performance ◽  
Growth Direction ◽  
Selective Exposure ◽  
Reduction Reaction ◽  
Carbon Supports ◽  
Step Method ◽  
Half Cell ◽  
Metal Precursors ◽  
One Step ◽  
Polymer Surfactant

The morphology of Pt-based nanoparticles supported on carbon is controlled to enhance the oxygen reduction reaction (ORR) catalytic performance. Herein a simple one-step method without a polymer surfactant is demonstrated to synthesize Pt-Cu nanoclusters, Pt-Cu nanospheres, and Cu-doped Pt nanoplates. Metal precursors are reduced in a NaCl or NH4Cl aqueous solution containing carbon supports, and nanoparticles are directly deposited on carbon. Cl− ions generated from NaCl or NH4Cl behave as oxidative etchants when O2 is dissolved in the synthesis solution, delaying the reduction of metal ions and leading to larger particles. Nanoclusters are obtained in the absence of Cl− ions. In addition, NH4+ guides the growth direction of Pt in the presence of oxidative etchants, forming a plate-like morphology that exposes the {111} facets. Half-cell measurements are performed in acidic media to evaluate the electrochemical properties. Cu-doped Pt nanoplates exhibit a 3.67-times higher ORR catalytic activity than the commercial Pt catalysts thanks to the synergistic effect with a small amount of Cu and selective exposure of the {111} facets. The result suggests that transition metals in Pt-based electrocatalysts may be unnecessary to form intermetallic alloyed crystals for the enhanced ORR performance.

scholarly journals Combining Carbon Fibers with Ni/γ–Al2O3 Used for Syngas Production: Part A: Preparation and Evaluation of Complex Carrier Catalysts

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 658 ◽  
Author(s):  
Lei Yu ◽  
Min Song ◽  
Yuexing Wei ◽  
Jun Xiao
Keyword(s):  
Carbon Fibers ◽  
Surface Characteristics ◽  
Temperature Programmed Desorption ◽  
Catalytic Performance ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Characterization Methods ◽  
Syngas Production ◽  
Good Surface ◽  
Temperature Programmed

To promote the adsorption and activation of carbon dioxide in the dry reforming of methane (DRM), Ni and Al2O3 were coprecipitated on activated carbon fibers (ACF). Various characterization methods were adopted in order to investigate the surface characteristics of different catalysts. Chemisorption characterization results, such as H2-temperature programmed reduction (H2-TPR), H2-temperature programmed desorption (H2-TPD), and CO2-temperature programmed desorption (CO2-TPD) illustrated that ACF in a nickel-based catalyst could enhance the basic sites and improve the metal dispersion on a catalyst surface, which is beneficial for the adsorption and activation of feed gas. The coprecipitated coating on ACF proved by scanning electron microscope (SEM) can prevent the carbon of ACF from participating in the reaction, while retain good surface properties of carbon fibers. X-ray diffraction (XRD) patterns illustrated that the ACF in a nickel-based catalyst could decrease the crystallite size of the spinel NiAl2O4, which is beneficial for methane reforming. In addition, the Fourier transform infrared spectroscopy (FTIR) of different catalysts revealed that the added ACF could provide abundant functional groups on the surface, which could be the intermediate product of DRM, and effectively promote the reaction. Different to the catalyst supported on single alumina, the performance evaluation and stability test proved that the catalyst added with ACF exhibited a better catalytic performance especially for CO2 conversion. Moreover, based on the characterization results as well as some related literature, the dry reforming mechanism over optimum catalyst was derived.

Colloidal synthesis of Pt–In bimetallic nanoparticles for propane dehydrogenation

2017 ◽  
Vol 95 (11) ◽  
pp. 1135-1140 ◽  
Author(s):  
Xuchun Wang ◽  
Di Yang ◽  
Yong Xu ◽  
Jun Zhong ◽  
Qiao Zhang
Keyword(s):  
High Stability ◽  
High Selectivity ◽  
Bimetallic Nanoparticles ◽  
Catalytic Performance ◽  
Propane Dehydrogenation ◽  
Colloidal Synthesis ◽  
Uniform Size ◽  
Dehydrogenation Reaction ◽  
One Step ◽  
Excellent Catalytic Performance

Recently, Pt-based bimetallic nanoparticles have drawn much attention because of their great catalytic performance and wide applications in diverse fields. In this work, we report that bimetallic Pt–In nanoparticles with uniform size distribution and controllable composition can be synthesized through a one-step, facile colloidal approach. Various characterization tools such as XRD, TEM, XPS, and synchrotron techniques have been used to characterize the as-obtained nanoparticles. It is demonstrated that the Pt and In elements are homogeneously distributed in the whole nanoparticle. The bimetallic Pt–In nanoparticles have shown great catalytic performance, including high activity, high selectivity, and high stability, for the propane dehydrogenation reaction to produce propene, one of the most important chemicals. The excellent catalytic performance makes Pt–In bimetallic nanoparticles promising catalysts in future industrial application.

Effect of Activation Duration in 1% Oxygen in Nitrogen Balance on Vanadium Phosphate Catalysts Synthesized via Sesquihydrate Route

2012 ◽  
Vol 554-556 ◽  
pp. 339-344
Author(s):  
Loong Kong Leong ◽  
Leeyien Thang
Keyword(s):  
Specific Surface ◽  
Nitrogen Balance ◽  
Temperature Programmed Desorption ◽  
Catalytic Performance ◽  
Temperature Programmed Reduction ◽  
Vanadium Phosphate ◽  
Hydrogen Phosphate ◽  
Average Oxidation State ◽  
Temperature Programmed ◽  
Surface Morphologies

Four vanadium phosphate catalysts were synthesized via vanadyl hydrogen phosphate sesquihydrate (VOHPO4•1.5H2O) route and activated at different duration (6, 18, 30 and 75 hours) in 1% oxygen/ nitrogen (1% O2/N2) mixture at 733K. The increased activation duration led to a decreased in the specific surface area of the catalysts. The increased activation duration increased the average oxidation state of vanadium. The surface morphologies of the catalysts exhibited plate-like crystals that agglomerated into clusters with folded edges. Temperature-programmed reduction (TPR) showed that increasing activation duration led to an increased in total amount of oxygen removed from the catalysts. Temperature-programmed desorption (TPD) showed that the total amount of oxygen desorbed from the catalysts increased as the activation duration increased. Catalytic performance revealed that all the catalysts produced possessed rather low in terms of activity but high in terms of selectivity.

Effects of SiO2/Al2O3 Ratio on Physicochemical Properties and Catalytic Performance of the Non-Templated ZSM-5 Zeolite

2011 ◽  
Vol 197-198 ◽  
pp. 992-995
Author(s):  
Wei Qiao Liu ◽  
Wei Ning Lei ◽  
Tong Ming Shang ◽  
Zhi Gang Mou ◽  
Heng Qiang Wang ◽  
...  
Keyword(s):  
Catalytic Properties ◽  
Temperature Programmed Desorption ◽  
Catalytic Performance ◽  
Acid Sites ◽  
X Ray Diffraction ◽  
Lewis Acid Sites ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
Temperature Programmed

The ZSM-5 zeolites of various SiO2/Al2O3ratios were synthesized without using any template agent. X-ray diffraction (XRD), transmission electron microscope (TEM), temperature- programmed desorption of ammonia (NH3-TPD) and Fourier transform infrared spectroscopy (FT-IR) techniques were employed to analyze the natures of the as-synthesized zeolite. The results show that the as-synthesized non-templated ZSM-5 zeolite is very pure. Meanwhile, Lewis acid sites and Bronsted acid sites are all presented in the as-synthesized non-templated HZSM-5 zeolite. The number of acid sites decreases almost linearly with the increasing of SiO2/Al2O3ratio of the zeolite. In addition, the reaction of propylene oligomerization was carried out over the as-synthesized non-templated HZSM-5 zeolite to evaluate the catalytic properties. The results show that the catalytic activity of propylene oligomerization decreases with the increasing of SiO2/Al2O3ratio.

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