OXIDATION OF GLYCEROL USING TITANIA SUPPORTED Au–Pd BIMETALLIC CATALYSTS: EFFECT OF Au–Pd RATIOS ON CATALYTIC PERFORMANCE

2011 ◽  
Vol 04 (03) ◽  
pp. 309-313 ◽  
Author(s):  
AINOL HAYAH AHMAD NADZRI ◽  
NORAINI HAMZAH ◽  
NIK IDRIS NIK YUSOFF ◽  
MOHD AMBAR YARMO
Keyword(s):  
Catalytic Activity ◽  
Bimetallic Catalysts ◽  
Catalytic Performance ◽  
Active Species ◽  
Precipitation Method ◽  
Oxidation Reactions ◽  
Pd Catalysts ◽  
Tartronic Acid ◽  
Pd Alloy ◽  
Urea Decomposition

Oxidation of glycerol to form various types of short chain oxygenated derivative compounds became an important reaction to support biodiesel industries. In this study, bimetallic Au–Pd catalysts supported on TiO2 with different Au/Pd atomic ratios have been successfully prepared by deposition-precipitation method with urea decomposition. The catalysts were tested in the glycerol oxidation reactions in order to examine the effect of Au–Pd ratio on the conversion and selectivity. Catalytic activity of all the catalysts were as follow: Au7Pd3/TiO2 > Au5Pd5/TiO2 > Au8Pd2/TiO2 > Au9Pd1/TiO2 > Au6Pd4/TiO2 . Analysis by XRD revealed the presence of metallic Au and gold-enriched Au–Pd alloy phase which were located between the [111] and [200] peaks of Au and Pd in the Au–Pd bimetallic catalysts. XPS analysis ascertained the formation of Au0 , Au3+ , Pd0 and PdO species together with Au–Pd alloy phase in the bimetallic Au–Pd catalysts. This shows that the catalytic activity of the catalysts was depended to the formation of mixture of active species namely Au0 , Au3+ , Pd0 dan PdO together with the presence of "synergisti" effect in the Au–Pd alloy. The reactions were performed at low and high temperatures (50°C and 100°C) and it was found that the selectivity to tartronic acid was enhanced at lower reaction temperature. The highest selectivity to tartronic acid (55% at 99% conversion) was obtained by using Au9Pd1/TiO2 at 50°C and after 8 h of reaction time.

Selective Oxidation of Glycerol over Titania Supported AuPd Bimetallic Catalysts

2010 ◽  
Vol 173 ◽  
pp. 155-160 ◽  
Author(s):  
Ainol Hayah Ahmad Nadzri ◽  
Noraini Hamzah ◽  
Aznira Alias ◽  
Jumat Salimon ◽  
Mohd Ambar Yarmo
Keyword(s):  
Catalytic Activity ◽  
Bimetallic Catalysts ◽  
Oxidation Reaction ◽  
Metal Particles ◽  
Precipitation Method ◽  
Xps Analysis ◽  
Phase Oxidation ◽  
Tartronic Acid ◽  
Tio2 Support ◽  
Pd Alloy

Oxidation of gycerol to form various types of important short chain oxygenated derivatives became an important reaction to support biodiesel industries. In this study, a series of AuPd nanoparticles at different metal mole ratios which were 9:1 and 8:2 supported on titania (TiO2) were successfully prepared, characterized and tested for its activity and selectivity in liquid phase oxidation reaction of glycerol. All the catalysts were prepared by deposition-precipitation method with decomposition of urea. AuxPdy/TiO2 catalysts were characterized using XRD, TEM and XPS. The formation of alloy Au-Pd phase was ascertained by XRD and XPS analysis. TEM analyses have shown that the Au and Pd metal particles in the range of 10-30 nm in size were uniformly dispersed on the TiO2 support with narrower size distribution. Higher catalytic activity observed for the catalysts was attributed to the presence of metallic Au0 and PdO phases together with the ‘synergistic’ effect of Au-Pd alloy. The highest selectivity to tartronic acid (55%) was obtained by using Au9Pd1/TiO2 catalyst after 8 h of reaction time at 50oC reaction temperature.

Catalytic Performance of SO2 by Colloidal Gold Supported on Nano γ-Fe2O3

2010 ◽  
Vol 178 ◽  
pp. 65-70 ◽  
Author(s):  
Sheng Rui Xu ◽  
Qin Shuai ◽  
Jin Hua Cheng ◽  
Xiao Ge Wang
Keyword(s):  
Gas Chromatography ◽  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Metal Oxides ◽  
Water Vapour ◽  
Colloidal Gold ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Sulfate Species

A new catalyst of gold supported on nanometal oxide for oxidation of SO2 was developed. Deposition-precipitation method was used to prepare gold-based catalysts. The catalytic activity of the catalysts was evaluated by determining the concentration of SO2 with gas chromatography under reaction temperature from 100 to 700°C. The results showed that there was an enhancement of catalytic activity when gold nanoparticles were dispersed on the surface of nano-metal oxides, furthermore, γ-Fe2O3 showed the highest activity as the support of the colloidal gold supported catalysts among the nanometal oxides including γ-Fe2O3, Fe2O3, ZnO, and Al2O3. It was also found that water vapour in the reaction enhanced the catalytic activity of Au/γ-Fe2O3. The Au/γ-Fe2O3 was characterized by XRD and FTIR methods, which indicated that the gold nanoparticles were dispersed on the γ-Fe2O3 support and sulfate species were formed on the surface of catalysts.

scholarly journals Enhanced Performance of Bimetallic Co-Pd Catalysts Prepared by Mechanical Alloying

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 335
Author(s):  
Steven Knauss ◽  
Laura Guevara ◽  
Mark Atwater
Keyword(s):  
Catalytic Activity ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Bimetallic Catalysts ◽  
Reactant Ratio ◽  
Pd Catalysts ◽  
Close Proximity ◽  
Intermediate Time ◽  
Underlying Mechanisms ◽  
Co Precipitation

Bimetallic catalysts can provide enhanced performance, and Co-based catalysts in particular have been studied in various respects for their activity in the deposition of carbon nanofibers (CNFs). The majority of studies on CNF catalysis use co-precipitation to create alloys, but recent work has demonstrated the suitability of mechanical alloying (MA) by ball milling to reduce cost and increase catalytic activity. This work establishes the unique ability of MA to control the microstructure to produce bimetallic composites, which retain distinct metallic phases that improve catalytic activity. It is demonstrated that Co-Pd alloys reach a maximum in catalytic activity at an intermediate time of mechanical activation, where 30 min of milling outperformed samples milled for 5, 15, 60, and 240 min at a reaction temperature of 550 °C and a 1:4 C2H4:H2 reactant ratio. This indicates there is benefit to retaining the metals in distinct phases in close proximity. Ball milling provides a relatively simple and scalable method to achieve these unique microstructures, and in the optimal condition tested here, the activity toward carbon deposition is increased fourfold over prior work. Furthermore, the minimum temperature for deposition is also reduced. The characteristics of these materials, the effects of milling and annealing, and the underlying mechanisms of deposition are discussed.

scholarly journals Effect of Y Modified Ceria Support in Mono and Bimetallic Pd–Au Catalysts for Complete Benzene Oxidation

Catalysts ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 283 ◽  
Author(s):  
Lyuba Ilieva ◽  
Anna Venezia ◽  
Petya Petrova ◽  
Giuseppe Pantaleo ◽  
Leonarda Liotta ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Benzene Oxidation ◽  
Total Oxidation ◽  
Pd Catalysts ◽  
X Ray ◽  
Close Relationship ◽  
Ceria Support ◽  
Co Precipitation

Mono metallic and bimetallic Pd (1 wt. %)–Au (3 wt. %) catalysts were prepared using two ceria supports doped with 1 wt. % Y2O3. Yttrium was added by impregnation or co-precipitation. The catalyst synthesis was carried out by deposition–precipitation method, with sequential deposition–precipitation of palladium over previously loaded gold in the case of the bimetallic samples. The obtained materials, characterized by X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (TPR) techniques, were tested in the complete benzene oxidation (CBO). The results of the characterization analyses and the catalytic performance pointed to a close relationship between structural, redox, and catalytic properties of mono and bimetallic catalysts. Among the monometallic systems, Pd catalysts were more active as compared to the corresponding Au catalysts. The bimetallic systems exhibited the best combustion activity. In particular, over Pd–Au supported on Y-impregnated ceria, 100% of benzene conversion towards total oxidation at the temperature of 150 °C was obtained. Comparison of surface sensitive XPS results of fresh and spent catalysts ascertained the redox character of the reaction.

Magnetic Spinel Ferrite: An Efficient, Reusable Nano Catalyst for HMFSynthesis

2021 ◽  
Vol 10 ◽  
Author(s):  
Jyoti Dhariwal ◽  
Ravina Yadav ◽  
Sheetal Yadav ◽  
Anshu Kumar Sinha ◽  
Chandra Mohan Srivastava ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Heterogeneous Catalysts ◽  
Spinel Ferrite ◽  
Active Surface ◽  
Catalytic Performance ◽  
Ferrite Nanoparticles ◽  
Precipitation Method ◽  
Magnetic Characteristics ◽  
Nano Catalyst

Aim: In the present work, the preparation and catalytic activity of spinel ferrite [MFe2O4; M = Fe, Mn, Co, Cu, Ni] nanoparticles to synthesize 5-hydroxymethylfurfural (HMF) have been discussed. Background: Ferrites possess unique physicochemical properties, including excellent magnetic characteristics, high specific surface area, active surface sites, high chemical stability, tunable shape and size, and easy functionalization. These properties make them essential heterogeneous catalysts in many organic reactions. Objective: This study aims to synthesize a series of transition metal ferrite nanoparticles and use them in the dehydration of carbohydrates for 5-hydroxymethylfurfural (HMF) synthesis. Method: The ferrite nanoparticles were prepared via the co-precipitation method, and PXRD confirmed their phase stability. The surface area and the crystallite size of the nanoparticles were calculated using BET and PXRD, respectively. Result: The easily prepared heterogeneous nanocatalyst showed a significant catalytic performance, and among all spinel ferrites, CuFe2O4 revealed maximum catalytic ability. Conclusion: Being a heterogeneous catalyst and magnetic in nature, ferrite nanoparticles were easily recovered by using an external magnet and reused up to several runs without substantial loss in catalytic activity. Others: HMF was synthesized from fructose in a good yield of 71%.

The Different Morphology of Co3O4 Catalysts and Application in the Abatement of Carbon Monoxide

2021 ◽  
Vol 21 (12) ◽  
pp. 6082-6087
Author(s):  
Chih-Wei Tang ◽  
Hsiang-Yu Shih ◽  
Ruei-Ci Wu ◽  
Chih-Chia Wang ◽  
Chen-Bin Wang
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Nitrogen Adsorption ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Adsorption Desorption

The increase of harmful carbon monoxide (CO) caused by incomplete combustion can affect human health even lead to suffocation. Therefore reducing the CO discharged by vehicles or factories is urgent to improve the air quality. The spinel cobalt (II, III) oxide (Co3O4) is an active catalyst for CO abatement. In this study, we tried to fabricate dispersing Co3O4 via the dispersion-precipitation method with acetic acid, formic acid, and oxalic acid as the chelating dispersants. Then, the asprepared samples were calcined at 300 ºC for 4 h to obtain active catalysts, and assigned as Co(A), Co(F) and Co(O) respectively, the amount of the dispersants used are labeled as I (0.12 mole), II (0.03 mole) and III (0.01 mole). For comparison, another CoAP sample was prepared via alkaliinduced precipitation and calcined at 300 ºC. All samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), scanning electron microscope (SEM), and nitrogen adsorption/desorption system, and the catalytic activity focused on the CO oxidation. The influence of chelating dispersant on the performance of abatement of CO was pursued in this study. Apparently, the results showed that the chelating dispersant can influence the catalytic activity of CO abatement. An optimized ratio of dispersant can improve the performance, while excess dispersant lessens the surface area and catalytic performance. The series of Co(O) samples can easily donate the active oxygen since the labile Co–O bonding and indicated the preferential performance than both Co(A) and Co(F) samples. The nanorod Co(O)-II showed preferential for CO oxidation, T50 and T90 approached 96 and 127 ºC, respectively. Also, the favorable durability of Co(O)-II sample maintains 95% conversion still for 50 h at 130 ºC and does not emerge deactivation.

Fabrication of hollow Cu2O@CuO-supported Au–Pd alloy nanoparticles with high catalytic activity through the galvanic replacement reaction

2015 ◽  
Vol 3 (8) ◽  
pp. 4578-4585 ◽  
Author(s):  
Wang Yao ◽  
Fei-Long Li ◽  
Hong-Xi Li ◽  
Jian-Ping Lang
Keyword(s):  
Catalytic Activity ◽  
Catalytic Performance ◽  
Galvanic Replacement ◽  
High Catalytic Activity ◽  
Alloy Nanoparticles ◽  
Galvanic Replacement Reaction ◽  
Replacement Reaction ◽  
Pd Alloy ◽  
Excellent Catalytic Performance

Cu2O@CuO-supported Au–Pd alloy nanoparticles prepared through the galvanic replacement approach exhibit an excellent catalytic performance in reducing 4-nitrophenol to 4-aminophenol.

scholarly journals The Study on the Active Site Regulated RuOx/Sn0.2Ti0.8O2 Catalysts with Different Ru Precursors for the Catalytic Oxidation of Dichloromethane

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1306
Author(s):  
Yang Yang ◽  
Zhong Zheng ◽  
Mengyue Kong ◽  
Zhesheng Hua ◽  
Zhengda Yang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Oxidation ◽  
Active Site ◽  
Catalytic Performance ◽  
Active Species ◽  
Utilization Efficiency ◽  
Active Components ◽  
Efficient Treatment ◽  
Oxidation Performance ◽  
Industrial Exhaust

Chlorine-containing volatile organic compounds (CVOCs) present in industrial exhaust gas can cause great harm to the human body and the environment. In order to further study the catalytic oxidation of CVOCs, an active site regulated RuOx/Sn0.2Ti0.8O2 catalyst with different Ru precursors was developed. With Dichloromethane as the model molecule, the activity test results showed that the optimization of Ru precursor using Ru colloid significantly increased the activity of the catalyst (T90 was reduced by about 90 °C when the Ru loading was 1 wt%). The analysis of characterization results showed that the improvement of the catalytic performance was mainly due to the improvement of the active species dispersion (the size of Ru cluster was reduced from 3–4 nm to about 1.3 nm) and the enhancement of the interaction between the active species and the support. The utilization efficiency of the active components was improved by nearly doubling TOF value, and the overall oxidation performance of the catalyst was also enhanced. The relationship between the Ru loading and the catalytic activity of the catalyst was also studied to better determine the optimal Ru loading. It could be found that with the increase in Ru loading, the dispersibility of RuOx species on the catalyst surface gradually decreased, despite the increase in their total amount. The combined influence of these two effects led to little change in the catalytic activity of the catalyst at first, and then a significant increase. Therefore, this research is meaningful for the efficient treatment of CVOCs and further reducing the content of active components in the catalysts.

Highly Active and Selective PtSnM1/γ-Al2O3 Catalyst for Direct Propane Dehydrogenation

2021 ◽  
Vol 43 (3) ◽  
pp. 342-342
Author(s):  
Arshid M Ali Arshid M Ali ◽  
Abdulrahim A Zahrani Abdulrahim A Zahrani ◽  
Muhammad A Daous Muhammad A Daous ◽  
Muhammad Umar Seetharamulu Podila and Lachezar A Petrov Muhammad Umar Seetharamulu Podila and Lachezar A Petrov
Keyword(s):  
Catalytic Activity ◽  
Coke Formation ◽  
Protective Layer ◽  
Catalytic Performance ◽  
Active Species ◽  
Propane Dehydrogenation ◽  
Propane Conversion ◽  
Feed Composition ◽  
Highly Active ◽  
Al2o3 Catalyst

This study is aimed to understand the role of alkaline earth elements (AEE) to the catalytic performance of PtSnM1/γ-Al2O3catalystfor the direct propane dehydrogenation (where M1 = Mg, Ca, Sr, Ba). All the catalysts were prepared by using wet impregnation.The overall catalytic performance of all the catalysts was studied at different reaction temperatures, feed composition ratios and GHSV. The best operating reaction conditions were575and#186;C, feed composition ratio of C3H8:H2:N2 = 1.0:0.5:5.5 and GHSV of 3800h-1. An optimal addition of “Ca” to PtSn//γ-Al2O3 catalyst, enhanced the catalytic activity of PtSnM1/γ-Al2O3 catalyst in comparison to other studied AEE. This catalyst had shown the highest propane conversion (~ 55.8 %) with 95.7 % propylene selectivity and least coke formation (7.11 mg.g-1h-1). In general, the increased catalytic activity of PtSnM1/γ-Al2O3 is attributed to the reduced coking extent during the reaction. In addition, the enhanced thermal stability of the PtSnCa/γ-Al2O3catalystis because of the protective layer betweenγ-Al2O3 and active metal, which allows the formation of active species such as PtSn, PtCa2 and Pt2Al phases?

Catalytic Performance of Supported Bimetallic Catalysts for Complete Oxidation of Toluene

2021 ◽  
Vol 21 (7) ◽  
pp. 4060-4066
Author(s):  
Sang-Chul Jung ◽  
Young-Kwon Park ◽  
Ho-Young Jung ◽  
Sang Chai Kim
Keyword(s):  
Catalytic Activity ◽  
Transition Metal ◽  
Bimetallic Catalysts ◽  
Xrd Analysis ◽  
Catalytic Performance ◽  
Bet Surface Area ◽  
Complete Oxidation ◽  
Transmission Electron ◽  
The Difference ◽  
Temperature Programmed

The complete oxidation of toluene (as a model volatile organic compound) was studied to determine the influence of adding a transition metal (Mn, Cr, Fe, Co, and Ni) to the 5 Cu/Al catalyst. The physcochemical properties of the catalysts were characterized by Brunauer–Emmett–Teller (BET) surface area analysis, X-ray diffraction (XRD) analysis, field emission transmission electron microscopy (FE/TEM), and hydrogen temperature programmed reduction (H2-TPR). The catalytic activity of the supported bimetallic catalysts followed the order: 5Cu-5Mn/Al > 5Cu-5Cr/Al > 5Cu-5Fe/Al > 5Cu-5Co/Al > 5Cu > 5Cu-5Ni/Al, based on the temperature for T90 of toluene conversion (T90). Two different reaction mechanisms (mixing and the synergistic effect) were operative in the supported bimetallic catalysts except for the 5Cu–5Mn/Al and 5Cu–5Ni/Al catalysts, on the basis of the reaction temperature. The difference between the electronegativity of copper and the added transition metal was associated with the catalytic activity.

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