scholarly journals Mixed Cerium/Zirconium Oxide as a Material for Carbon Monoxide Thermocatalytic Gas Sensor

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 841
Author(s):  
Nikolay Samotaev ◽  
Alexey Vasiliev
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Co Oxidation ◽  
Gas Sensors ◽  
Zirconium Oxide ◽  
Sensor Response ◽  
Pd Catalysts ◽  
Co Concentration ◽  
Inert Carrier ◽  
Response Light

The perspective catalysts usable for the fabrication of thermocatalytic gas sensors were studied. The analysis of CO oxidation kinetics by Pd decorated Al2O3, ZSM-5, SnO2, CeO2/ZrO2 and some other carriers of catalysts showed that the application of these catalysts leads to the ambiguity of sensor response (light-off effect). It was demonstrated that a catalyst based on CeO2/ZrO2 carrier could be used for the fabrication of sensors characterized by the univocal correspondence between CO concentration and sensor response. The developed model of the CO oxidation on all Pd catalysts with inert carrier enabled the description of the CO oxidation using a single value of activation energy.

Bimetallic Co and Mn Supported on Hydroxyapatite Catalyst for Carbon Monoxide Oxidation at Lower Temperature

2021 ◽  
Author(s):  
Rahul More ◽  
Pavan More
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Co Oxidation ◽  
Bimetallic Catalyst ◽  
Active Species ◽  
Deposition Method ◽  
Oxidation Of Co ◽  
Oxidation Activity ◽  
Lower Temperature ◽  
Monometallic Catalyst

Abstract The series of bimetallic Co and Mn supported on hydroxyapatite catalyst were prepared by successive deposition method and examined for CO oxidation. The CO oxidation activity was compared with monometallic Mn/HAp and Co/HAp. The catalysts are characterized in detail and correlated to the oxidation activity. The XRD, XPS and TPR characterization showed the presence of more facile Co2+, Mn3+ and adsorbed oxygen due to the interaction between Mn and Co. The 0.4 mol Mn and 0.1 mol Mn deposited on HAp showed formation of maximum active species. The maximum CoO species was observed over bimetallic catalyst compared to the monometallic catalyst. These active lower the activation energy require for CO and oxygen. These species were responsible for the oxidation of CO at lower temperature compared to the remaining catalyst.

scholarly journals Encapsulation Process and Materials Evaluation for E-Textile Gas Sensor

Proceedings ◽  
2019 ◽  
Vol 32 (1) ◽  
pp. 8
Author(s):  
Ashwini Valavan ◽  
Komolafe ◽  
Harris ◽  
Beeby
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Dioxide ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Sensor Response ◽  
Vehicular Emissions ◽  
Pollution Levels ◽  
Encapsulation Process ◽  
Novel Method ◽  
Exposure Levels

The degree of pollution in the environment increases because of the vehicular emissions such as carbon monoxide (CO) and nitrogen dioxide (NO2) gases. To minimize the exposure levels, it is necessary for individuals to be able to determine for themselves the pollution levels of the environments they are in so that they can take the necessary precautions. Textile-based gas sensors are an emerging solution and this paper furthers the concept by investigating a novel method for encapsulating gas sensors in textiles. While encapsulation is required to improve the durability and lifetime of the sensors, it essential for their operation that the encapsulants do not reduce the sensitivity of the gas sensor. This paper investigates the selectivity of two different flexible and breathable thermoplastic encapsulants (Platilon®U and Zitex G-104) for sensing carbon monoxide by observing the sensor response with and without the encapsulants. Results show that while the encapsulants both enable the sensor to still function, Platilon®U reduces the sensor sensitivity, whereas Zitex G-104 has very little effect.

scholarly journals Kinetics of the Carbon Monoxide Oxidation Reaction Under Microwave Heating

1996 ◽  
Vol 430 ◽  
Author(s):  
W. Lee Perry ◽  
Joel D. Katz ◽  
Daniel Rees ◽  
Mark T. Paffett ◽  
Abhaya Datye
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Co Oxidation ◽  
Microwave Heating ◽  
Oxidation Reaction ◽  
Reaction Order ◽  
Thermal Gradients ◽  
Exponential Factor ◽  
Co Oxidation Reaction ◽  
Kinetics Of

Abstract915 MHz microwave heating has been used to drive the CO oxidation reaction over Pd/Al2O3 without significantly affecting the reaction kinetics. As compared to an identical conventionally heated system, the activation energy, pre-exponential factor, and reaction order with respect to CO were unchanged. Temperature was measured using a thermocouple extrapolation technique. Microwave-induced thermal gradients were found to play a significant role in kinetic observations.

Carbon monoxide oxidation by chemolithotrophic ammonium oxidizers

1983 ◽  
Vol 29 (11) ◽  
pp. 1545-1551 ◽  
Author(s):  
Ronald D. Jones ◽  
Richard Y. Morita
Keyword(s):  
Carbon Monoxide ◽  
Co Oxidation ◽  
Time Course ◽  
Nitrosomonas Europaea ◽  
Nitrifying Bacteria ◽  
Oxidation Rates ◽  
Co Concentration ◽  
Presence And Absence ◽  
Cellular Components ◽  
Nitrosococcus Oceanus

Chemolithotrophic nitrifying bacteria were examined with respect to their ability to oxidize carbon monoxide in the presence and absence of ammonium. All of the ammonium oxidizers tested, including Nitrosomonas europaea and Nitrosococcus oceanus, were able to oxidize CO to CO2 in the presence and absence of ammonium. None of the organisms tested incorporated any of the carbon from CO into cellular components in the absence of ammonium. All were able to oxidize CO at trace concentrations of <0.5 nM. None of the nitrite oxidizers examined were capable of CO oxidation. CO oxidation by Nitrosomonas europaea, Nitrosococcus oceanus, and Nitrosomonas sp. 4S30, a marine ammonium oxidizer, were examined with respect to CO concentration and time course of CO oxidation, both in the presence and absence of 10 mg/L NH4 N. The CO oxidation rates at a CO concentration of 300 nL/L in the absence of ammonium ranged from 0.048 nmol/h per 106 cells for Nitrosomonas sp. 4W30 to 0.0025 nmol/h per 106 cells for N. europaea.

Oxidation of carbon monoxide by oxygen over pure and platinum-doped LaMnO3 perovskites

1990 ◽  
Vol 55 (8) ◽  
pp. 1928-1934 ◽  
Author(s):  
Jaroslav Bartoň ◽  
Vladimír Pour
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Apparent Activation Energy ◽  
Co Oxidation ◽  
Reaction Kinetics ◽  
Empirical Equation ◽  
Catalytic Activities ◽  
Surface Areas ◽  
Oxidation Of Carbon Monoxide

The properties of pure and platinum-doped LaMnO3 perovskites, including their catalytic activities for the reaction of CO with oxygen, have been determined. Perovskite samples were prepared by decomposition of lanthanum and manganese citrates. The surface areas were 12.2 m2/g for pure LaMnO3 and 9.8 m2/g for the platinum-doped sample. The doping with a small amount of platinum markedly enhances the catalytic activity of LaMnO3 perovskite. The (CO + O2) reaction starts at 200 °C over LaMnO3 and at temperatures below 100 °C over a sample doped with Pt. The reaction kinetics for both the pure and platinum-doped LaMnO3 can be described by empirical equation (4). When Pt-doped perovskite is used, an increase in the apparent activation energy occurs at about 150 °C. This fact is attributed to a change in the mechanism of CO oxidation.

Palladium Promoted Copolymerization of Carbon Monoxide with Polar or Nonpolar Olefinic Monomers

2020 ◽  
Vol 24 ◽  
Author(s):  
Yanlin Zong ◽  
Qiankun Li ◽  
Hongliang Mu ◽  
Zhongbao Jian
Keyword(s):  
Carbon Monoxide ◽  
Physical Properties ◽  
Vinyl Monomers ◽  
Pd Catalysts ◽  
Catalytic Systems

Abstract:: The copolymers of carbon monoxide (CO) and olefins, namely polyketones, are a family of widely used materi-als. In the catalytic preparation of these materials, palladium(II) catalysts represent the most successful catalytic systems. The production of both alternating and non-alternating polyketones has been achieved, with great difference in their physical properties. Herein, a variety of palladium(II) catalysts employed for the copolymerization of CO with various olefinic mon-omers such as ethylene, α-olefins, styrene and polar vinyl monomers are fully summarized. The influence of important fac-tors such as solvents and counterions on specific copolymerization, is also discussed. This review aims to enlighten the de-sign of new Pd catalysts with improved properties, as well as the development of new polyketone materials.

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 The Activating Effect of Strong Acid for Pd-Catalyzed Directed C–H Activation by Concerted Metalation-Deprotonation Mechanism

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4083
Author(s):  
Heming Jiang ◽  
Tian-Yu Sun
Keyword(s):  
Activation Energy ◽  
Dft Calculations ◽  
Energy Barrier ◽  
Computational Study ◽  
Strong Acid ◽  
Activation Energy Barrier ◽  
Pd Catalysts ◽  
Acid Ligand ◽  
Strong Acids

A computational study on the origin of the activating effect for Pd-catalyzed directed C–H activation by the concerted metalation-deprotonation (CMD) mechanism is conducted. DFT calculations indicate that strong acids can make Pd catalysts coordinate with directing groups (DGs) of the substrates more strongly and lower the C–H activation energy barrier. For the CMD mechanism, the electrophilicity of the Pd center and the basicity of the corresponding acid ligand for deprotonating the C–H bond are vital to the overall C–H activation energy barrier. Furthermore, this rule might disclose the role of some additives for C–H activation.

scholarly journals Unique structure of active platinum-bismuth site for oxidation of carbon monoxide

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bing Nan ◽  
Qiang Fu ◽  
Jing Yu ◽  
Miao Shu ◽  
Lu-Lu Zhou ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Low Temperature ◽  
Co Oxidation ◽  
Density Functional ◽  
Technology Development ◽  
Co Adsorption ◽  
Combustion Engines ◽  
Advanced Combustion ◽  
Surface Metal ◽  
Bismuth Cluster

AbstractAs the technology development, the future advanced combustion engines must be designed to perform at a low temperature. Thus, it is a great challenge to synthesize high active and stable catalysts to resolve exhaust below 100 °C. Here, we report that bismuth as a dopant is added to form platinum-bismuth cluster on silica for CO oxidation. The highly reducible oxygen species provided by surface metal-oxide (M-O) interface could be activated by CO at low temperature (~50 °C) with a high CO2 production rate of 487 μmolCO2·gPt−1·s−1 at 110 °C. Experiment data combined with density functional calculation (DFT) results demonstrate that Pt cluster with surface Pt−O−Bi structure is the active site for CO oxidation via providing moderate CO adsorption and activating CO molecules with electron transformation between platinum atom and carbon monoxide. These findings provide a unique and general approach towards design of potential excellent performance catalysts for redox reaction.

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