Vapor-phase Oxidation of Cyclohexane over Supported Fe-Mn Catalysts: In-Situ DRIFTS studies

2021 ◽  
Author(s):  
Vijendra Kumar Yadav ◽  
Taraknath Das
Keyword(s):  
Surface Area ◽  
Raman Spectra ◽  
Vapor Phase ◽  
Oxide Catalysts ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
In Situ Drifts ◽  
Mn Oxide ◽  
Phase Oxidation

Alumina-supported Fe-Mn oxide catalysts were synthesized by the incipient wetness impregnation method. The catalysts were characterized by using various characterization techniques such as surface area, XRD, H2-TPR, and Raman spectra...

scholarly journals Insight into the Promoting Role of Er Modification on SO2 Resistance for NH3-SCR at Low Temperature over FeMn/TiO2 Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 618
Author(s):  
Huan Du ◽  
Zhitao Han ◽  
Xitian Wu ◽  
Chenglong Li ◽  
Yu Gao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalyst Surface ◽  
Impregnation Method ◽  
In Situ Drifts ◽  
Tio2 Catalyst ◽  
Nh3 Scr ◽  
Nh3 Adsorption ◽  
So2 Resistance ◽  
Fast Scr

Er-modified FeMn/TiO2 catalysts were prepared through the wet impregnation method, and their NH3-SCR activities were tested. The results showed that Er modification could obviously promote SO2 resistance of FeMn/TiO2 catalysts at a low temperature. The promoting effect and mechanism were explored in detail using various techniques, such as BET, XRD, H2-TPR, XPS, TG, and in-situ DRIFTS. The characterization results indicated that Er modification on FeMn/TiO2 catalysts could increase the Mn4+ concentration and surface chemisorbed labile oxygen ratio, which was favorable for NO oxidation to NO2, further accelerating low-temperature SCR activity through the “fast SCR” reaction. As fast SCR reaction could accelerate the consumption of adsorbed NH3 species, it would benefit to restrain the competitive adsorption of SO2 and limit the reaction between adsorbed SO2 and NH3 species. XPS results indicated that ammonium sulfates and Mn sulfates formed were found on Er-modified FeMn/TiO2 catalyst surface seemed much less than those on FeMn/TiO2 catalyst surface, suggested that Er modification was helpful for reducing the generation or deposition of sulfate salts on the catalyst surface. According to in-situ DRIFTS the results of, the presence of SO2 in feeding gas imposed a stronger impact on the NO adsorption than NH3 adsorption on Lewis acid sites of Er-modified FeMn/TiO2 catalysts, gradually making NH3-SCR reaction to proceed in E–R mechanism rather than L–H mechanism. DRIFTS.

scholarly journals Effect of Zirconia Polymorph on Vapor-Phase Ketonization of Propionic Acid

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 768 ◽  
Author(s):  
Shuang Ding ◽  
Jiankang Zhao ◽  
Qiang Yu
Keyword(s):  
Propionic Acid ◽  
Vapor Phase ◽  
Surface Concentration ◽  
X Ray Diffraction ◽  
In Situ Drifts ◽  
X Ray ◽  
Surface Intermediates ◽  
Temperature Programmed ◽  
Diffuse Reflectance Infrared

Vapor-phase ketonization of propionic acid derived from biomass was studied at 300–375 °C over ZrO2 with different zirconia polymorph. The tetragonal ZrO2 (t-ZrO2) are more active than monoclinic ZrO2 (m-ZrO2). The results of characterizations from X-ray diffraction (XRD) and Raman suggest m-ZrO2 and t-ZrO2 are synthesized by the solvothermal method. NH3 and CO2 temperature-programmed desorption (NH3-TPD and CO2-TPD) measurements show that there were more medium-strength Lewis acid base sites with lower coordination exposed on m-ZrO2 relative to t-ZrO2, increasing the adsorption strength of propionic acid. The in situ DRIFTS (Diffuse reflectance infrared Fourier transform spectroscopy) of adsorbed propionic acid under ketonization reaction reveal that as the most abundant surface intermediates, the monodentate propionates are more active than bidentate propionates. In comparison with m-ZrO2, the t-ZrO2 surface favors monodentate adsorption over bidentate adsorption. Additionally, the adsorption strength of monodentate propionate is weaker on t-ZrO2. These differences in adsorption configuration and adsorption strength of propionic acid are affected by the zirconia structure. The higher surface concentration and weaker adsorption strength of monodentate propionates contribute to the higher ketonization rate in the steady state.

scholarly journals Catalytic Combustion of Propane over Pt-Mo/ZSM-5 Catalyst: The Promotional Effects of Molybdenum

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1377
Author(s):  
Zhenan Liao ◽  
Kaiwen Zha ◽  
Wenjie Sun ◽  
Zhen Huang ◽  
Hualong Xu ◽  
...  
Keyword(s):  
Catalytic Combustion ◽  
Impregnation Method ◽  
Turnover Frequency ◽  
Propane Combustion ◽  
In Situ Drifts ◽  
Positive Correlation ◽  
Catalytic Stability ◽  
Molybdenum Doping

To improve propane combustion activity and illustrate the promotional effects of molybdenum doping, Pt-Mo/ZSM-5 catalysts with different Mo amounts were prepared by the co-impregnation method. XRD, Raman, H2-TPR, NH3-TPD, in situ DRIFTs, XPS and other characterizations were performed. The results indicated that the concentration of Pt0 in Pt/ZSM-5 catalyst increased after the doping of Mo and the content of Pt0 had a positive correlation with the reaction turnover frequency value. The propane combustion activity of Pt/ZSM-5 catalyst was significantly improved after the doping of molybdenum species. Among all the catalysts, Pt-6Mo/ZSM-5 catalyst (Pt/ZSM-5 with 6 wt.% Mo modification) showed the lowest T50 and T90 for propane catalytic combustion. Moreover, the Pt-Mo/ZSM-5 catalyst exhibited outstanding catalytic stability.

Novel Base Catalysts by Nitridation of Zeolite Y: Characterization and Catalytic Evaluation

2010 ◽  
Vol 148-149 ◽  
pp. 1096-1099
Author(s):  
Gong Ming Peng ◽  
De Lian Yi ◽  
Lin Wu ◽  
Zhao Hui Ou Yang ◽  
Jian Guo Wang
Keyword(s):  
Surface Area ◽  
Zeolite Y ◽  
High Surface ◽  
High Surface Area ◽  
Diethyl Malonate ◽  
Bet Surface Area ◽  
In Situ Drifts ◽  
Base Catalysts ◽  
Diffuse Reflectance Infrared

Novel base catalysts were obtained by subjecting Y zeolites to nitridation. These materials were characterized by elemental analysis, X-ray diffraction, BET surface area analysis, In situ diffuse reflectance infrared fourier transform Spectroscopy (in situ DRIFTS), Pyrrole adsorption. The results indicated nitrogen-incorporated NaY zeolite was well ordered and possess high surface area and pore volume. In situ DRIFTS experiments confirmed that N atoms had been introduced into the framework by nitridation to form -NH2- or -NH- species. It was found that Lewis basicity of these oxynitride materials increased by the pyrrole adsorption. Furthmore, the basic catalytic properties of nitrogen-incorporated zeolites were evaluated by Knoevenagal condensation of benzaldehyde with diethyl malonate and enhanced yield of product was achieved.

An In Situ SEM-FIB-Based Method for Contrast Enhancement and Tomographic Reconstruction for Structural Quantification of Porous Carbon Electrodes

2014 ◽  
Vol 20 (5) ◽  
pp. 1576-1580 ◽  
Author(s):  
Santhana K. Eswara-Moorthy ◽  
Prasanth Balasubramanian ◽  
Willem van Mierlo ◽  
Jörg Bernhard ◽  
Mario Marinaro ◽  
...  
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Porous Carbon ◽  
Tomographic Reconstruction ◽  
Vacuum Impregnation ◽  
Solid Boundary ◽  
Carbon Electrodes ◽  
Impregnation Method ◽  
Porous Carbon Electrodes

AbstractA new in situ Scanning Electron Microscope-Focused Ion Beam-based method to study porous carbon electrodes involving Pt filling of pores from gaseous precursors has been demonstrated to show drastically improved image contrast between the carbon and porous phases when compared with the Si-resin vacuum-impregnation method. Whereas, the latter method offered up to 20% contrast, the new method offers remarkably higher contrast (42%), which enabled fast semi-automated demarcation of carbon boundaries and subsequent binarization of the images with very high fidelity. Tomographic reconstruction of the porous carbon electrode was then obtained from which several morphological parameters were quantified. The porosity was found to be 72±2%. The axial and radial tortuosites were 1.45±0.04 and 1.43±0.04, respectively. Pore size, which is defined to be the distance from the medial axis of the pore to the nearest solid boundary, was quantified. Average pore size determined from the pore size distribution was 90 nm and the corresponding 1 sigma ranges from 45 to 134 nm. Surface-to-volume ratio of the carbon phase was 46.5 µm−1. The ratio of total surface area to the total volume of electrode including pores (i.e., specific surface area) was 13 µm−1.

Synthesized BG-MCM-41 as Support Catalyst for Fenton-Like Reaction of Lignin Degradation

2014 ◽  
Vol 931-932 ◽  
pp. 12-16
Author(s):  
Pongsert Sriprom ◽  
Arthit Neramittagapong ◽  
Sutasinee Neramittagapong
Keyword(s):  
Aqueous Solution ◽  
Surface Area ◽  
Lignin Degradation ◽  
Batch Reactor ◽  
Bet Surface Area ◽  
Impregnation Method ◽  
Hydrothermal Technique ◽  
The Stability ◽  
Mcm 41

Lignin was degraded by Fenton-like reaction using Cu-BG-MCM41, in which BG-MCM41 was synthesized by hydrothermal technique from Bagasse ash (BG) as a support. Cu was immobilized on BG-MCM41 by in situ hydrothermal and impregnation method and characterized by XRD and BET surface area. The Fenton-like reactions were carried out in a batch reactor using 5wt%CuO/SiO2, 10wt%CuO/SiO2, 5wt%Cu-BG-MCM41 and 10wt%Cu-BG-MCM41 at the pH of 3 and the temperature of 80°C. The Cu loading, pH, and temperature affected lignin degradation. The efficiency of lignin degradation obtained were 95% for 5wt%CuO/SiO2, 95% for 10wt%CuO/SiO2, 65% for 5wt%Cu-BG-MCM41 and 96% for 10wt%Cu-BG-MCM41 at the pH of 3 and 80°C for 30 min. The results show that pH and temperature affected the stability of Cu loading, in which it was leached into the aqueous solution and that the reaction will occur in the aqueous solution more than on the surface of catalyst. Thus, 5wt%Cu-BG-MCM41 has the highest stability for Fenton-like reactions.

scholarly journals Multifunctional and Environmentally Friendly TiO2–SiO2 Mesoporous Materials for Sustainable Green Buildings

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4226
Author(s):  
Ghedini ◽  
Menegazzo ◽  
Manzoli ◽  
Di Michele ◽  
Puglia ◽  
...  
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Environmentally Friendly ◽  
Green Building ◽  
Structural Features ◽  
Modulated Dsc ◽  
Synthetic Approach ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method

This work deals with the formulation of environmentally friendly, cheap, and readily-available materials for green building applications, providing the function of air purificator by improving the safety and the comfort of an indoor environment. High surface area TiO2–SiO2 samples, prepared by a simple, cost effective, and scalable synthetic approach, proved to be effective in maximizing the properties of each component, i.e., the photocatalytic properties of titania and the high surface area of silica. TiO2 was introduced onto an ordered mesoporous silica Santa Barbara Amorphous-15 (SBA-15), that is featured by interesting insulating features, by using an incipient wetness impregnation method. The photocatalytic activity was evaluated in gas phase oxidation of ethylbenzene, which was selected as model volatile organic compound (VOC) molecule. The morphological, textural and structural features along with the electronic properties, the hydrophilicity and heat capacity of the materials were investigated in depth by scanning electron microscopy, powder X-ray diffraction, N2 physisorption, diffuse reflectance UV-Vis, FT-IR spectroscopies, and modulated DSC (MDSC) dynamic scan. Outstanding performances in the ethylbenzene abatement results are promising for further application in the green building sector.

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