Influence of the Calcination Temperature on the Catalytic Properties of Os/Bentonite for Glycerol Hydrogenolysis

2017 ◽  
Vol 888 ◽  
pp. 518-523
Author(s):  
Noraini Hamzah ◽  
Wan Zurina Samad ◽  
Mohd Ambar Yarmo
Keyword(s):  
Calcination Temperature ◽  
Catalytic Properties ◽  
Low Cost ◽  
Metal Species ◽  
Xps Analysis ◽  
Glycerol Conversion ◽  
Green Route ◽  
Catalytic Hydrogenolysis ◽  
Glycerol Hydrogenolysis ◽  
Characterization Studies

Selective catalytic hydrogenolysis of glycerol on Os/bentonite catalyst represents a low cost and green route for 1,2-propanediol which is major commonity chemical used in the production of antifreeze functional fluids, paints and humectants. The experimental results combined with the characterization studies using TPR, FESEM-EDX and XPS techiniques revealed that the optimum calcination temperature was 300 °C with glycerol conversion obtained was 80.7%. This might be due to the presense of Os metal species as a active site with binding energy (BE) of Os 4f at 51.2 eV in XPS analysis. TPR profile also shows two obvious peak at reduction temperature of 95 °C and 140 °C represent for Os3+ and Os4+ species respectively. The presence of Os3+ and Os4+ species were also confirmed by XPS analysis.

scholarly journals Gasification of Glycerol Over Ni/γ-Al2O3 For Hydrogen Production: Tailoring Catalytic Properties to Control Deactivation

2020 ◽  
Vol 7 (1) ◽  
pp. 65-74
Author(s):  
Ahmed Umar ◽  
John T.S. Irvine
Keyword(s):  
Calcination Temperature ◽  
Catalyst Deactivation ◽  
Catalytic Properties ◽  
Catalyst System ◽  
Catalyst Loading ◽  
Glycerol Conversion ◽  
Calcination Temperatures ◽  
Metal Support ◽  
Size Growth ◽  
Low Performance

AbstractThe effects of catalyst loading, calcination and reaction temperatures on the structural properties and catalytic behavior of Ni/γ-Al2O3 catalyst system in relation to steam reforming of glycerol and catalyst deactivation were investigated. The results showed that catalyst loading, reaction and calcination temperatures had a profound influence on the structure and catalytic activity in glycerol conversion. Use of high calcination temperature (900-1000 °C) led to phase transformation of the active Ni/Al2O3 to less active spinel specie NiAl2O4 that resulted in a successive change of texture and color. The particle size growth and phase change at this temperature were responsible for the catalyst deactivation and low performance especially among the catalyst calcined at high temperatures. Conversely, at low reaction temperatures, catalyst surfaces were marred by carbon deposition. Whilethe polymeric carbon deposited at metal-support interface was associated with low reaction temperatures, high reaction temperatures were characterized predominantly by both amorphous carbon deposited on the active metal surface and polymeric or graphitic carbon deposited at metal-support interface respectively. Calcination temperature showed no significant influence on the location and type of coke deposited on the catalyst surface. Hence, catalyst loading, calcination and reaction temperatures could be tailored to enhance structural and catalytic properties and guard against catalyst deactivation.

scholarly journals Glycerol Hydrogenolysis with In Situ Hydrogen Produced via Methanol Steam Reforming: The Promoting Effect of Pd on a Cu/ZnO/Al2O3 Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 110
Author(s):  
Yuanqing Liu ◽  
Chau T. Q. Mai ◽  
Flora T. T. Ng
Keyword(s):  
Steam Reforming ◽  
Catalyst Activity ◽  
Promoting Effect ◽  
Glycerol Conversion ◽  
Glycerol Hydrogenolysis ◽  
Glycerol Dehydration ◽  
Effect Of Pd ◽  
Al2o3 Catalyst ◽  
Reaction Equilibrium

The glycerol hydrogenolysis to produce 1,2-propanediol without using externally supplied hydrogen was investigated using methanol present in crude glycerol to provide in situ hydrogen via its steam reforming reaction. This paper focuses on the promoting effect of Pd on the reactivity of a Cu/Zn/Al2O3 catalyst. Adding 2 wt% Pd onto a Cu/ZnO/Al2O3 catalyst significantly improved the selectivity to 1,2-propanediol from 63.0% to 82.4% and the glycerol conversion from 70.2% to 99.4%. This enhancement on the catalytic activity by Pd is mainly due to the improved hydrogenation of acetol, which is the intermediate formed during the glycerol dehydration. The rapid hydrogenation of acetol can shift the reaction equilibrium of glycerol dehydration forward resulting in a higher glycerol conversion. The improved reducibility of the catalyst by Pd allows the catalyst to be reduced in situ during the reaction preventing any loss of catalyst activity due to any potential oxidation of the catalyst. The catalyst was slightly deactivated when it was firstly recycled resulting in a 5.4% loss of glycerol conversion due to the aggregation of Cu and the deactivation became less noticeable upon further recycling.

scholarly journals A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 594 ◽  
Author(s):  
Mara Serrapede ◽  
Marco Fontana ◽  
Arnaud Gigot ◽  
Marco Armandi ◽  
Glenda Biasotto ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
Low Cost ◽  
Xps Analysis ◽  
3D Scaffold ◽  
Energy Storage Devices ◽  
Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

scholarly journals The Importance of Thermal Treatment on Wet-Kneaded Silica–Magnesia Catalyst and Lebedev Ethanol-to-Butadiene Process

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 579
Author(s):  
Sang-Ho Chung ◽  
Adrian Ramirez ◽  
Tuiana Shoinkhorova ◽  
Ildar Mukhambetov ◽  
Edy Abou-Hamad ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Calcination Temperature ◽  
Catalytic Properties ◽  
Catalyst Preparation ◽  
Preparation Methods ◽  
Calcination Temperatures ◽  
Alternative Process ◽  
Magnesium Silicates

The Lebedev process, in which ethanol is catalytically converted into 1,3-butadiene, is an alternative process for the production of this commodity chemical. Silica–magnesia (SiO2–MgO) is a benchmark catalyst for the Lebedev process. Among the different preparation methods, the SiO2–MgO catalysts prepared by wet-kneading typically perform best owing to the surface magnesium silicates formed during wet-kneading. Although the thermal treatment is of pivotal importance as a last step in the catalyst preparation, the effect of the calcination temperature of the wet-kneaded SiO2–MgO on the Lebedev process has not been clarified yet. Here, we prepared and characterized in detail a series of wet-kneaded SiO2–MgO catalysts using varying calcination temperatures. We find that the thermal treatment largely influences the type of magnesium silicates, which have different catalytic properties. Our results suggest that the structurally ill-defined amorphous magnesium silicates and lizardite are responsible for the production of ethylene. Further, we argue that forsterite, which has been conventionally considered detrimental for the formation of ethylene, favors the formation of butadiene, especially when combined with stevensite.

Rhenium-promoted Pt/WO3/ZrO2: an efficient catalyst for aqueous glycerol hydrogenolysis under reduced H2 pressure

RSC Advances ◽  
2016 ◽  
Vol 6 (89) ◽  
pp. 86663-86672 ◽  
Author(s):  
Qing Tong ◽  
Anyi Zong ◽  
Wei Gong ◽  
Lei Yu ◽  
Yining Fan
Keyword(s):  
Catalyst Surface ◽  
Surface Acidity ◽  
Efficient Catalyst ◽  
Glycerol Conversion ◽  
Glycerol Hydrogenolysis

Re improved the dispersion of Pt in Pt/WO3/ZrO2 and enhanced the catalyst surface acidity. Pt–Re/WO3/ZrO2 afforded glycerol conversion >99% and C3 alcohol selectivity >95%. The reactions were performed under reduced H2 pressure.

Effect of calcination temperature on the morphology and catalytic properties of ZnO nanostructures fabricated from a chiral precursor for photodegradation of both cationic and anionic dyes

2022 ◽  
Author(s):  
Shradha Gandhi ◽  
Rupinder Kaur ◽  
Vandana Sharma ◽  
Sanjay Mandal
Keyword(s):  
Calcination Temperature ◽  
Catalytic Properties ◽  
Zno Nanostructures ◽  
Anionic Dyes ◽  
Different Temperatures

Diverse ZnO nanostructures (ZnO_1 to ZnO_3) were synthesized by direct calcination of a chiral MOF precursor {[Zn4(µ3-OH)2(D-2,4-cbs)2(H2O)4].5H2O}n (Zn-CBS) at three different temperatures 600, 700 and 800 oC, respectively. On the...

Progress in Catalytic Preparation of Carbon/Carbon Composites

2013 ◽  
Vol 634-638 ◽  
pp. 2004-2008
Author(s):  
Bing Ju Li ◽  
Jun Li ◽  
Lei Shi ◽  
Zhou Jian Tan ◽  
Ji Qiao Liao
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Catalytic Properties ◽  
Low Cost ◽  
Chemical Vapor ◽  
Carbon Composites ◽  
Catalytic Chemical Vapor Deposition ◽  
Vapor Deposition Technique ◽  
Development Tendency ◽  
Published Research

This paper reviewed published research into catalytic fabrication techniques and recent progresses of carbon/carbon (C/C) composites. It’s described the catalytic chemical vapor deposition theory and reviewed the catalytic properties of different metal catalysts. Merits and demerits of the traditional chemical vapor deposition, improved chemical vapor deposition and other new rapid densification techniques were analyzed. The new densification techniques are to shorten the preparation cycle, but most of them are limited in the laboratory with application problems. Finally, the prospect on the application and development tendency of improved catalytic chemical vapor deposition technique is put forward in the rapid low cost fabrication of C/C composites in the future.

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