scholarly journals Synthesis of Graphene-Based Biopolymer TiO2 Electrodes Using Pyrolytic Direct Deposition Method and its Catalytic Performance

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1050
Author(s):  
Parminder Kaur ◽  
Sana Frindy ◽  
Yuri Park ◽  
Mika Sillanpää ◽  
Monzur A. Imteaz
Keyword(s):  
Catalytic Activity ◽  
Municipal Wastewater ◽  
Catalytic Performance ◽  
Optimum Process ◽  
Self Healing ◽  
Pharmaceutical Drugs ◽  
Operational Parameters ◽  
Graphene Layers ◽  
Good Catalytic Activity ◽  
Chitosan Biopolymer

The traditional methods used to synthesize graphene layers over semiconductors are chemical-based methods. In the present investigation, a novel photoelectroactive electrode was synthesized using a chitosan biopolymer without the usage of chemicals. A chitosan-biopolymer layer over the surface of TiO2 was generated by electrodeposition. Furthermore, the pyrolysis method was used for the conversion of a biopolymer into graphene layers. The catalytic activity of the fabricated electrodes was investigated by the photo-electro-Fenton (PEF) process to oxidize chloramphenicol and nadolol pharmaceutical drugs in wastewater, remove metals (scandium, neodymium, and arsenic) and degrade real municipal wastewater. The PEF operational parameters (pH, voltage, reaction time, and Fenton catalytic dose) were optimized for the overall degradation of chloramphenicol and nadolol pharmaceutical drugs in wastewater. It was observed that at the optimum process operational parameters it took 40 min to degrade chloramphenicol and nadolol pharmaceutical drugs in wastewater. It was proved that biopolymer-based photoelectroactive novel electrodes render good catalytic activity. Furthermore, the reusability study of fabricated electrodes showed excellent storage and self-healing properties.

A nona-vacant Keggin-type tricarbonyl rhenium derivative {[PMo3O16][Re(CO)3]4}5− and its catalytic performance for CO2 cycloaddition reactions

RSC Advances ◽  
2015 ◽  
Vol 5 (84) ◽  
pp. 69006-69009 ◽  
Author(s):  
Zhiyuan Huo ◽  
Jipeng Guo ◽  
Jingkun Lu ◽  
Qiaofei Xu ◽  
Pengtao Ma ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Cycloaddition Reaction ◽  
Catalytic Performance ◽  
Cycloaddition Reactions ◽  
Frontier Orbitals ◽  
Keggin Type ◽  
Good Catalytic Activity

A nona-vacant Keggin-type tricarbonyl rhenium derivative {[PMo3O16][Re(CO)3]4}5− was synthesized and its frontier orbitals were computed. Interestingly, it showed good catalytic activity for the CO2 cycloaddition reaction.

Catalytic Synthesis of Dioctyl Phthalate over Al-MCM-41 Molecular Sieves

2011 ◽  
Vol 306-307 ◽  
pp. 1741-1746
Author(s):  
Hua Feng Zhou ◽  
Yong Jin Yang ◽  
Jin Son Zhang
Keyword(s):  
Catalytic Activity ◽  
Molecular Sieves ◽  
Hydrothermal Process ◽  
Analytical Techniques ◽  
Catalytic Performance ◽  
Dioctyl Phthalate ◽  
Catalytic Synthesis ◽  
Al Content ◽  
Good Catalytic Activity ◽  
Mcm 41

In this paper, mesoporous MCM-41 and Al-MCM-41(Si/Al =100, 70, 40, 10, 5) molecular sieves were synthesized by direct hydrothermal process and characterized by various analytical techniques. Their catalytic performance in the synthesis of dioctyl phthalate (DOP) was also studied. The results show that while keeping the mesostructure of Al-MCM-41(Si/Al=100, 70, 40), increasing Al content can increase the acidity and so forth effectively improve the catalytic activity. But too much aluminum incorporation can destroy the structure of Al-MCM-41(Si/Al=10). The Al-MCM-41 molecular sieves with proper Si/Al ratios have good catalytic activity and stability in DOP synthesis. When Al-MCM-41(40) was used as the catalyst, A high PA conversion of 98.45% can be reached in 4 h. After being reused for five times, Al-MCM-41(40) still remains good catalytic activity.

scholarly journals Efficient Production of Methyl Oleate Using a Biomass-Based Solid Polymeric Catalyst with High Acid Density

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Anping Wang ◽  
Heng Zhang ◽  
Hu Li ◽  
Song Yang
Keyword(s):  
Catalytic Activity ◽  
Oleic Acid ◽  
Methyl Oleate ◽  
Low Cost ◽  
Catalytic Performance ◽  
Raw Material ◽  
Efficient Production ◽  
High Acid ◽  
High Efficient ◽  
Good Catalytic Activity

Biomass-based polymers are eco-friendly, nontoxic and biodegradable materials. In this work, in order to prepare green, low-cost and high-efficient catalysts under mild conditions, we chose biomass-based chitosan as raw material and prepared a new solid acidic catalyst by an acid functionalization method. FT-IR, XRD, SEM, TGA, BET, neutralization titration and other analytical methods were used to characterize the catalyst. The results showed that CS-SO3H morphology exhibited a sphere of about 10 μm diameter, and the acid density was as high as 3.81 mmol/g. The catalyst exhibits good catalytic activity in the esterification of oleic acid and methanol, which is a model reaction of the pre-esterification process in the preparation of biodiesel from feedstocks with high acid values. Under the optimum reaction conditions (15/1 methanol/oleic acid mole ratio and 3 wt% catalyst dosage at 75°C for 3 h), the yield of methyl oleate can reach 95.7%. Even if the mass of oleic acid in the reactant increased to 20 g, solid acid showed good catalytic performance, and the yield of methyl oleate was 94.4%. After four times of reuse, the yield of the catalyst can still reach 85.7%, which indicates that the catalyst has good catalytic activity and stability, and has potential application prospects.

High resolution electron microscopy of lanthanum phosphate crystals

1978 ◽  
Vol 36 (1) ◽  
pp. 274-275
Author(s):  
J. C. Wheatley ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
High Resolution ◽  
Petroleum Industry ◽  
High Resolution Electron Microscopy ◽  
Lanthanum Phosphate ◽  
Good Catalyst ◽  
Resolution Electron ◽  
Good Catalytic Activity ◽  
Physical And Chemical

Rare-earth phosphates are of particular interest because of their catalytic properties associated with the hydrolysis of many aromatic chlorides in the petroleum industry. Lanthanum phosphates (LaPO4) which have been doped with small amounts of copper have shown increased catalytic activity (1). However the physical and chemical characteristics of the samples leading to good catalytic activity are not known.Many catalysts are amorphous and thus do not easily lend themselves to methods of investigation which would include electron microscopy. However, the LaPO4, crystals are quite suitable samples for high resolution techniques.The samples used were obtained from William L. Kehl of Gulf Research and Development Company. The electron microscopy was carried out on a JEOL JEM-100B which had been modified for high resolution microscopy (2). Standard high resolution techniques were employed. Three different sample types were observed: 669A-1-5-7 (poor catalyst), H-L-2 (good catalyst) and 27-011 (good catalyst).

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
Author(s):  
Zhao-Meng Wang ◽  
Li-Juan Liu ◽  
Bo Xiang ◽  
Yue Wang ◽  
Ya-Jing Lyu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Catalytic Performance ◽  
Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

scholarly journals CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 131 ◽  
Author(s):  
Rola Mohammad Al Soubaihi ◽  
Khaled Mohammad Saoud ◽  
Myo Tay Zar Myint ◽  
Mats A. Göthelid ◽  
Joydeep Dutta
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Active Sites ◽  
Bond Activation ◽  
Dissociative Adsorption ◽  
High Catalytic Activity ◽  
Good Catalytic Activity ◽  
Pretreatment Conditions ◽  
Oxidation Efficiency

Carbon monoxide (CO) oxidation is considered an important reaction in heterogeneous industrial catalysis and has been extensively studied. Pd supported on SiO2 aerogel catalysts exhibit good catalytic activity toward this reaction owing to their CO bond activation capability and thermal stability. Pd/SiO2 catalysts were investigated using carbon monoxide (CO) oxidation as a model reaction. The catalyst becomes active, and the conversion increases after the temperature reaches the ignition temperature (Tig). A normal hysteresis in carbon monoxide (CO) oxidation has been observed, where the catalysts continue to exhibit high catalytic activity (CO conversion remains at 100%) during the extinction even at temperatures lower than Tig. The catalyst was characterized using BET, TEM, XPS, TGA-DSC, and FTIR. In this work, the influence of pretreatment conditions and stability of the active sites on the catalytic activity and hysteresis is presented. The CO oxidation on the Pd/SiO2 catalyst has been attributed to the dissociative adsorption of molecular oxygen and the activation of the C-O bond, followed by diffusion of adsorbates at Tig to form CO2. Whereas, the hysteresis has been explained by the enhanced stability of the active site caused by thermal effects, pretreatment conditions, Pd-SiO2 support interaction, and PdO formation and decomposition.

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 A diffusion anisotropy descriptor links morphology effects of H-ZSM-5 zeolites to their catalytic cracking performance

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiaoliang Liu ◽  
Jing Shi ◽  
Guang Yang ◽  
Jian Zhou ◽  
Chuanming Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Cracking ◽  
Catalytic Performance ◽  
Zeolite Catalysts ◽  
Time Resolved ◽  
Cracking Performance ◽  
Morphology Effect ◽  
Ft Ir ◽  
The Difference ◽  
Dynamics Simulations

AbstractZeolite morphology is crucial in determining their catalytic activity, selectivity and stability, but quantitative descriptors of such a morphology effect are challenging to define. Here we introduce a descriptor that accounts for the morphology effect in the catalytic performances of H-ZSM-5 zeolite for C4 olefin catalytic cracking. A series of H-ZSM-5 zeolites with similar sheet-like morphology but different c-axis lengths were synthesized. We found that the catalytic activity and stability is improved in samples with longer c-axis. Combining time-resolved in-situ FT-IR spectroscopy with molecular dynamics simulations, we show that the difference in catalytic performance can be attributed to the anisotropy of the intracrystalline diffusive propensity of the olefins in different channels. Our descriptor offers mechanistic insight for the design of highly effective zeolite catalysts for olefin cracking.

scholarly journals Performance Analysis of TiO2-Modified Co/MgAl2O4 Catalyst for Dry Reforming of Methane in a Fixed Bed Reactor for Syngas (H2, CO) Production

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3347
Author(s):  
Arslan Mazhar ◽  
Asif Hussain Khoja ◽  
Abul Kalam Azad ◽  
Faisal Mushtaq ◽  
Salman Raza Naqvi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Dry Reforming ◽  
Fixed Bed Reactor ◽  
Dry Reforming Of Methane ◽  
Catalyst Stability ◽  
Feed Ratio ◽  
Catalyst Loading ◽  
Impregnation Method

Co/TiO2–MgAl2O4 was investigated in a fixed bed reactor for the dry reforming of methane (DRM) process. Co/TiO2–MgAl2O4 was prepared by modified co-precipitation, followed by the hydrothermal method. The active metal Co was loaded via the wetness impregnation method. The prepared catalyst was characterized by XRD, SEM, TGA, and FTIR. The performance of Co/TiO2–MgAl2O4 for the DRM process was investigated in a reactor with a temperature of 750 °C, a feed ratio (CO2/CH4) of 1, a catalyst loading of 0.5 g, and a feed flow rate of 20 mL min−1. The effect of support interaction with metal and the composite were studied for catalytic activity, the composite showing significantly improved results. Moreover, among the tested Co loadings, 5 wt% Co over the TiO2–MgAl2O4 composite shows the best catalytic performance. The 5%Co/TiO2–MgAl2O4 improved the CH4 and CO2 conversion by up to 70% and 80%, respectively, while the selectivity of H2 and CO improved to 43% and 46.5%, respectively. The achieved H2/CO ratio of 0.9 was due to the excess amount of CO produced because of the higher conversion rate of CO2 and the surface carbon reaction with oxygen species. Furthermore, in a time on stream (TOS) test, the catalyst exhibited 75 h of stability with significant catalytic activity. Catalyst potential lies in catalyst stability and performance results, thus encouraging the further investigation and use of the catalyst for the long-run DRM process.

Three-dimensionally ordered macroporous spinel-type MCr2O4 (M = Co, Ni, Zn, Mn) catalysts with highly enhanced catalytic performance for soot combustion

2015 ◽  
Vol 5 (9) ◽  
pp. 4594-4601 ◽  
Author(s):  
Jinguo Wang ◽  
Gaoyang Yang ◽  
Li Cheng ◽  
Eun Woo Shin ◽  
Yong Men
Keyword(s):  
Catalytic Activity ◽  
Three Dimensional ◽  
Catalytic Performance ◽  
Soot Combustion ◽  
Spinel Type ◽  
Ordered Macroporous

MCr2O4 catalysts with three-dimensional ordered macroporous structures displayed superior catalytic activity for soot combustion to their bulk counterparts.

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