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.

The effect of different metal oxides on the catalytic activity of a Co3O4 catalyst for toluene combustion: importance of the structure–property relationship and surface active species

2019 ◽  
Vol 43 (27) ◽  
pp. 10868-10877 ◽  
Author(s):  
Xuejun Zhang ◽  
Min Zhao ◽  
Zhongxian Song ◽  
Heng Zhao ◽  
Wei Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Metal Oxides ◽  
Catalytic Oxidation ◽  
Active Species ◽  
Active Oxygen ◽  
Redox Cycle ◽  
Structure Property ◽  
Property Relationship ◽  
Structure Property Relationship ◽  
Surface Active

The Co–La catalyst was used to the catalytic oxidation of toluene. The LaCoO3 perovskite was detected. The abundance of Co3+ and active oxygen contributed synergistically to the redox cycle reaction, which could improve the catalytic activity.

scholarly journals Single-atom Sn-Zn pairs in CuO catalyst promote dimethyldichlorosilane synthesis

2019 ◽  
Vol 7 (3) ◽  
pp. 600-608 ◽  
Author(s):  
Qi Shi ◽  
Yongjun Ji ◽  
Wenxin Chen ◽  
Yongxia Zhu ◽  
Jing Li ◽  
...  
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Catalytic Performance ◽  
Utilization Efficiency ◽  
Single Atom ◽  
Electronic Interaction ◽  
Active Components ◽  
Functional Theory ◽  
Low Concentrations ◽  
Sn Substitution

Abstract Single-atom catalysts are of great interest because they can maximize the atom-utilization efficiency and generate unique catalytic properties; however, much attention has been paid to single-site active components, rarely to catalyst promoters. Promoters can significantly affect the activity and selectivity of a catalyst, even at their low concentrations in catalysts. In this work, we designed and synthesized CuO catalysts with atomically dispersed co-promoters of Sn and Zn. When used as the catalyst in the Rochow reaction for the synthesis of dimethyldichlorosilane, this catalyst exhibited much-enhanced activity, selectivity and stability compared with the conventional CuO catalysts with promoters in the form of nanoparticles. Density functional theory calculations demonstrate that single-atomic Sn substitution in the CuO surface can enrich surface Cu vacancies and promote dispersion of Zn to its atomic levels. Sn and Zn single sites as the co-promoters cooperatively generate electronic interaction with the CuO support, which further facilitates the adsorption of the reactant molecules on the surface, thereby leading to the superior catalytic performance.

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?

scholarly journals Catalytic Oxidation of HCHO over the Sodium-Treated Sepiolite-Supported Rare Earth (La, Eu, Dy, and Tm) Oxide Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 328 ◽  
Author(s):  
Ning Dong ◽  
Qing Ye ◽  
Mengyue Chen ◽  
Shuiyuan Cheng ◽  
Tianfang Kang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Rare Earth ◽  
Catalytic Oxidation ◽  
Rare Earth Oxide ◽  
Catalytic Performance ◽  
Rare Earth Oxides ◽  
Hydroxyl Groups ◽  
In Situ Drifts ◽  
The Rare Earth

The sodium-treated sepiolite (NaSep)-supported rare earth oxide (RE/NaSep; RE = La, Eu, Dy, and Tm) samples were prepared using the rotary evaporation method. Physicochemical properties of these materials were characterized by XRD, SEM, BET, FTIR, XPS, H2–TPR, NH3–TPD, and in situ DRIFTS, and their catalytic activities for formaldehyde (HCHO) (2000 ppm) oxidation were evaluated. The results show that loading of the rare earth oxide on NaSep improved its catalytic performance. Among all the samples, Eu/NaSep performed the best, and complete HCHO conversion was achieved at a temperature of 150 °C and a gas hourly space velocity of 240,000 mL/(g h); a good catalytic activity was still maintained after 45 h of stability test. The catalytic oxidation mechanism of HCHO was studied using the in situ DRIFTS technique. As a result, the effective and stable catalytic performance of the Eu/NaSep sample was mainly due to the presence of hydroxyl groups on the sepiolite surface and the doped rare earth oxides, which contributed to its high performance. HCHO oxidation underwent via the steps of HCHO + O2 → HCOO− + OH− → H2O + CO2. It is concluded that the optimal catalytic activity of Eu/NaSep was associated with the highest Oads/Olatt atomic ratio, the largest amount of hydroxyl groups, the highest acidity, and the best reducibility. The present work may provide new insights into the application in the removal of high-concentration HCHO over the rare earth oxides supported on natural low-cost clays.

Preparation of Aromatic Aldehydes from Lignin Oxidation with a Perovskite-Type Catalyst

2011 ◽  
Vol 80-81 ◽  
pp. 350-354 ◽  
Author(s):  
Bin Wang ◽  
Zhu Long
Keyword(s):  
Catalytic Oxidation ◽  
Doping Concentration ◽  
Sol Gel ◽  
Aromatic Aldehydes ◽  
Average Diameter ◽  
Catalytic Performance ◽  
Doping Amount ◽  
Chemical Homogeneity ◽  
Oxidation Performance ◽  
B Doping

In order to study the morphology and catalytic oxidation performance of LaMnO3 nanoparticles after A or B site doping , the sol-gel methods is applied, the La1-xSrxMnO3 and LaCuxMn1-xO3（x=0.1, 0.2, 0.3, 0.4, 0.5) nanoparticles are prepared. The diameter of particles and morphology-distribution of naniparticles with different doping amounts are analyzed by X-ray diffraction (XRD), scan electric microscope (SEM) and related software. With the framework of the experiment, the average diameter of particles is between 16-21nm with better chemical homogeneity and have higher surface area. At the same time, the catalytic oxidation of nanoparticle under different doping amounts is also studied. Tests results show that nanoparticle has excellent catalytic oxidation performance, and with the increase of doping amount, the catalytic activity of the particle increase first and decrease afterwards with the increase of A or B site doping amount, the best performance presents at X=0.2 of A or B doping concentration. The effect of lattice deformation arising from the dopants, which leads to the decrease of the catalytic performance, can not be ignored at higher doping concentration anymore. Under the same doping amounts, the catalytic performance of B-site doped is better than A-site.

Effect of SO2 on Mn-Mg-Ox Catalyst Treated by Non-Thermal Plasma for NO Catalytic Oxidation

2014 ◽  
Vol 989-994 ◽  
pp. 490-493
Author(s):  
Rui Yun Lai ◽  
Xiao Long Tang ◽  
Hong Hong Yi ◽  
Kai Li ◽  
Ying Xiang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Catalytic Oxidation ◽  
Thermal Plasma ◽  
Active Site ◽  
Competitive Adsorption ◽  
Temperature Range ◽  
Catalytic Active Site ◽  
Ft Ir ◽  
Non Thermal Plasma

The effect of MgO addition on SO2tolerance of MnOxfor the NO catalytic oxidation was investigated in this work. MgO addition significantly promotes the SO2resistance of MnOxat low temperature range of 50–250°C. The slight decrease in catalytic activity over Mn-Mg-Oxexposure to SO2is attributed to the partially deactivation of the catalytic active site poisoned by SO2. Through XRD and FT-IR characterization, MgO may effectively inhibit the competitive adsorption between NOxand SO2in manganese site, and enhance SO2adsorption on the magnesia surface.

Synthesis and Characterization of CuMnOx-Bentonite as Efficient Catalyst for Oxidation of m-xylene

2020 ◽  
Vol 42 (4) ◽  
pp. 504-504
Author(s):  
Mo Thi Nguyen Mo Thi Nguyen ◽  
Cam Minh Le Cam Minh Le ◽  
Tuan Minh Nguyen Tuan Minh Nguyen ◽  
Hao Hoang Nguyen Hao Hoang Nguyen ◽  
Anwar ul Haq Ali Shah Hung Van Hoang Anwar ul Haq Ali Shah Hung Van Hoang
Keyword(s):  
Catalytic Activity ◽  
Catalytic Oxidation ◽  
Catalytic Performance ◽  
Morphological Characterization ◽  
Efficient Catalyst ◽  
Tem Analysis ◽  
Different Temperatures ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Xrd And Tem

Catalytic oxidation of organic volatile compounds (VOCs) is considered superior to conventional methods because very low concentration of VOCs can also be oxidized and removed at low temperatures without consumption of addditional fuel and introduction of NOx compounds into the environment. Herein, the synthesis of MnO2 nanoparticles on bentonite (Bent) support in the presence of CuO for catalytic oxidation of m-xylene is reported. The synthesized materials were analyzed with FT-IR, XRD, and TEM analysis for structural and morphological characterization. XRD and TEM analysis indicated the formation of δ-MnO2 with sheet structure on Bent surface. Temperature-programmed reduction (H2-TPR) of hydrogen was used to investigate catalytic performance of δ-MnO2 towards oxidation of m-xylene at different temperatures. The catalytic activity was strongly dependent on the δ-MnO2 content in the synthesized material. 100 % oxidation of m-xylene with observed with 10% Mn content at temperature below than 325 oC. Intersetingly introduction of CuO greatly improved the catalytic activity of Mn-Bent materials. The presence of Cu in Mn-Bent has greatly reduced the temperature for complete oxidation of m-xylene. In this case100% conversion of m-xylene was observed at 250 oC.

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.

Thermal Treatment Effect on Catalytic Activity of Au/TiO2 for CO Oxidation

2014 ◽  
Vol 548-549 ◽  
pp. 254-258
Author(s):  
Asif Mahmood ◽  
Shahid M. Ramay ◽  
Yousef Al-Zeghayer ◽  
Sajjad Haider ◽  
Muhammad Ali Shar ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Thermal Treatment ◽  
Co Oxidation ◽  
Oxidation Reaction ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Preferential Oxidation ◽  
Reaction Heat ◽  
Oxidation Performance ◽  
Positive Effect

A novel and well-organized study for the synthesis and enhanced catalytic activity of Au/TiO2catalysts has been developed. A momentous improvement in the catalytic activity of Au/TiO2in CO oxidation and preferential oxidation reaction by thermal treatment has been studied. Au/TiO2catalyst (Au (1 wt.%) supported on TiO2) was prepared by conventional deposition-precipitation method with NaOH followed by washing, drying and calcination in air at 400 °C for 4 h. Thermal treatment of Au/TiO2was performed at 450 °C under 0.05 mTorr. The activity of the catalysts has been examined in the reaction of CO oxidation and preferential oxidation (PROX) at 25-250 °C. The catalytic performance was found to be strongly affected by thermal treatment of the prepared catalyst prior to the reaction. Heat treatment after Au deposition has a positive effect on the CO oxidation performance. This is attributed to the introduction of a stronger interaction between the oxide and Au which improves the catalytic activity.

Research of Catalytic Performance over Transition Metal Modified MnOx-CeOx/ACF Catalysts

2011 ◽  
Vol 383-390 ◽  
pp. 1945-1950 ◽  
Author(s):  
Bo Xiong Shen ◽  
Ting Liu ◽  
Ning Zhao ◽  
Juan Ma ◽  
Xiao Cui Hao
Keyword(s):  
Catalytic Activity ◽  
Thermal Treatment ◽  
Transition Metal ◽  
Catalytic Reduction ◽  
Surface Acidity ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Active Components ◽  
Scr Of No ◽  
Negative Effect

The catalyst of MnOx-CeOx/ACF prepared by impregnation method was used for low-temperature selective catalytic reduction (SCR) of NO with NH3, and more than 90% NO conversion was obtained at 230°C. Fe、Cu or V was used respectively to prepare transition metal modified MnOx-CeOx/ ACF catalysts which had lower catalytic activity than that over MnOx-CeOx/ACF. SEM, N2 adsorption and NH3-TPD were used to analyze the catalysts. The results showed that transition metal modified catalysts had a reduced surface area, pore volume and surface acidity. SO2 had a negative effect on SCR performance of the catalysts. Fe modified catalyst exhibited SO2 tolerance in the first 6h in the presence of 100ppm SO2. Thermal treatment in N2 at 350°C was used to regenerate the deactivated catalysts by SO2. The decomposition of ammonium salts recovered the catalytic activity to some extent. The sulfated active components in deactivated catalysts after the thermal treatment enhanced the surface acidity of the catalysts.

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