Polymer oxidation catalyst containing acidic functional groups

1981 ◽  
Vol 46 (5) ◽  
pp. 1237-1247
Author(s):  
Zdeněk Prokop ◽  
Karel Setínek
Keyword(s):  
Functional Groups ◽  
Elevated Temperatures ◽  
Redox Properties ◽  
Oxidation Catalyst ◽  
Carbon Clusters ◽  
Oxidation Activity ◽  
Redox Sites ◽  
Styrene Divinylbenzene ◽  
Proportional Decrease ◽  
Polymer Oxidation

The catalyst containing redox sites in addition to acid functional groups was prepared by sulphonation of a macroporous chloromethylated styrene-divinylbenzene copolymer with concentrated sulphuric acid at elevated temperatures. Its activity was tested for the oxidation of 2-propanol by molecular oxygen at 120 °C and was found to be comparable to that of the iridium on carbon catalyst.Neutralisation of acid functional groups by alkali metal led to proportional decrease in the oxidation activity. The results of EPR spectroscopic study of these catalysts show that the redox properties of the polymer are caused by carbon clusters which are capable of electron exchange.

Styrene-divinylbenzene polymer oxidation catalyst

1981 ◽  
Vol 46 (11) ◽  
pp. 2657-2662
Author(s):  
Zdeněk Prokop ◽  
Karel Setínek
Keyword(s):  
Functional Groups ◽  
Noble Metal ◽  
Additional Data ◽  
Catalytic Properties ◽  
Metal Catalysts ◽  
Oxidation Catalyst ◽  
Noble Metal Catalysts ◽  
Polymer Catalyst ◽  
Styrene Divinylbenzene ◽  
Polymer Oxidation

Some additional data about properties and applicability of a styrene-divinylbenzene polymer catalyst containing acidic and redox functional groups are reported. It is shown that the catalysts of this type can be prepared reproducibly and exhibit catalytic properties comparable to the properties of noble metal catalysts.

scholarly journals Dual role of CO in the stability of subnano Pt clusters at the Fe3O4(001) surface

2016 ◽  
Vol 113 (32) ◽  
pp. 8921-8926 ◽  
Author(s):  
Roland Bliem ◽  
Jessi E. S. van der Hoeven ◽  
Jan Hulva ◽  
Jiri Pavelec ◽  
Oscar Gamba ◽  
...  
Keyword(s):  
Density Functional ◽  
Elevated Temperatures ◽  
Time Lapse ◽  
Dual Role ◽  
Oxidation Catalyst ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Active Metal ◽  
Catalytically Active ◽  
The Stability

Interactions between catalytically active metal particles and reactant gases depend strongly on the particle size, particularly in the subnanometer regime where the addition of just one atom can induce substantial changes in stability, morphology, and reactivity. Here, time-lapse scanning tunneling microscopy (STM) and density functional theory (DFT)-based calculations are used to study how CO exposure affects the stability of Pt adatoms and subnano clusters at the Fe3O4(001) surface, a model CO oxidation catalyst. The results reveal that CO plays a dual role: first, it induces mobility among otherwise stable Pt adatoms through the formation of Pt carbonyls (Pt1–CO), leading to agglomeration into subnano clusters. Second, the presence of the CO stabilizes the smallest clusters against decay at room temperature, significantly modifying the growth kinetics. At elevated temperatures, CO desorption results in a partial redispersion and recovery of the Pt adatom phase.

Double graphitic-N doping for enhanced catalytic oxidation activity of carbocatalysts

2019 ◽  
Vol 21 (10) ◽  
pp. 5481-5488 ◽  
Author(s):  
Meiling Hou ◽  
Xin Zhang ◽  
Shandong Yuan ◽  
Wanglai Cen
Keyword(s):  
Work Function ◽  
Catalytic Oxidation ◽  
Functional Groups ◽  
Reactive Oxygen ◽  
Catalytic Efficiency ◽  
Oxidation Activity ◽  
Promotion Effect ◽  
Oxygen Functional Groups ◽  
N Doping

Double-GrN remarkably enhanced the catalytic efficiency for O2 dissociation reactions and accelerates the generation of highly chemically reactive oxygen functional groups. The promotion effect is ascribed to the reduction of the work function of carbocatalysts due to N doping, which facilitates the transfer of electrons from carbocatalysts to the adsorbed O2 molecules for their activation.

Influence of Fiber’s Surface State on Mechanical Properties and Fiber-Matrix Interaction of CFRP

2013 ◽  
Vol 690-693 ◽  
pp. 323-328
Author(s):  
J. J. Sha ◽  
Y.X. Zhang ◽  
J. Li ◽  
J. X. Dai ◽  
Z. Q. Wei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Functional Groups ◽  
Carbon Fibers ◽  
Surface State ◽  
Elevated Temperatures ◽  
Fiber Surface ◽  
Flexural Test ◽  
Matrix Interaction ◽  
Fiber Matrix

In order to investigate the influence of carbon fiber’s surface state on the mechanical properties and the fiber-matrix interaction of CFRP, the change of surface state was achieved by thermal treatment of carbon fibers at elevated temperatures, and the surface state was characterized by XPS. The mechanical properties were measured from the flexural test. The CFRP reinforced with 600 °C treated fabrics containing the highest reactive functional groups, showed the highest flexural strength and modulus. But in the case of CFRP reinforced with 1500 °C treated fabrics containing the lowest reactive functional groups, exhibited the lowest flexural strength and modulus. Combining the mechanical properties with the microstructure analysis, the results indicated that the fiber-matrix interaction (strong or weak) depends on the relative percentage of reactive functional groups present on the carbon fiber surface.

scholarly journals CoOx nanoparticle anchored on sulfonated-graphite as efficient water oxidation catalyst

2017 ◽  
Vol 8 (9) ◽  
pp. 6111-6116 ◽  
Author(s):  
Jingqi Guan ◽  
Chunmei Ding ◽  
Ruotian Chen ◽  
Baokun Huang ◽  
Xianwen Zhang ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Oxidation Catalyst ◽  
Oxidation Activity ◽  
Solar Water ◽  
Highly Efficient ◽  
Solar Water Oxidation

Ultrasmall CoOx nanoparticles on sulfonated graphite exhibit highly efficient water oxidation activity and can be used for electrochemical and solar water oxidation.

scholarly journals Evaluation of NO Oxidation Properties over a Mn-Ce/γ-Al2O3Catalyst

2016 ◽  
Vol 2016 ◽  
pp. 1-5
Author(s):  
Pan Wang ◽  
Peng Luo ◽  
Junchen Yin ◽  
Lili Lei
Keyword(s):  
Electron Microscope ◽  
Sol Gel ◽  
Diesel Oxidation Catalyst ◽  
No Oxidation ◽  
Oxidation Catalyst ◽  
X Ray Diffraction ◽  
Oxidation Activity ◽  
Transmission Electron ◽  
Diesel Oxidation ◽  
Oxidation Properties

With the purpose of studying the effect of diesel oxidation catalyst (DOC) on the NO oxidation activity, a series ofxMn10Ce/γ-Al2O3(x= 4, 6, 8, and 10) catalysts were synthesized by acid-aided sol-gel method. The physicochemical properties of the catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Transmission Electron Microscope (TEM). Result showed that the crystalline size of MnOxand CeO2ranges from 5 nm to 30 nm and manganese existed mainly in the catalysts in the form of manganese dioxide. Moreover, NO oxidation experiments were carried out to evaluate the activity of the catalysts; according to the results, 6Mn10Ce/γ-Al2O3catalyst showed the supreme NO oxidation activity with a NO to NO2conversion rate of 83.5% at 300°C. Compared to 500 ppm NO inlet concentration, the NO conversion was higher than that of 750 and 1000 ppm NO over 6Mn10Ce/γ-Al2O3catalyst in the temperature range of 150–300°C.

scholarly journals Hydrothermal Aging of Pd/LTA Monolithic Catalyst for Complete CH4 Oxidation

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 517 ◽  
Author(s):  
Ida Friberg ◽  
Aiyong Wang ◽  
Louise Olsson
Keyword(s):  
Water Vapor ◽  
Catalyst Deactivation ◽  
Oxidation Catalyst ◽  
X Ray Diffraction ◽  
Ch4 Oxidation ◽  
Hydrothermal Aging ◽  
Oxidation Activity ◽  
X Ray ◽  
Lta Zeolite ◽  
Surface Hydroxyls

Palladium-based catalysts are known to provide high CH4 oxidation activity. One drawback for these materials is that they often lose activity in the presence of water vapor due to the formation of surface hydroxyls. It is however possible to improve the water vapor tolerance by using zeolites as support material. In this study, we have investigated Pd supported on thermally stable LTA zeolite with high framework Si/Al ratio (Si/Al = ~44) for CH4 oxidation and the effect of hydrothermal aging at temperatures up to 900 °C. High and stable CH4 oxidation activity in the presence of water vapor was observed for Pd/LTA after hydrothermal aging at temperatures ≤ 700 °C. However, aging at temperatures of 800–900 °C resulted in catalyst deactivation. This deactivation was not a result of structural collapse of the LTA zeolite as the LTA zeolite only showed minor changes in surface area, pore volume, and X-ray diffraction pattern after 900 °C aging. We suggest that the deactivation was caused by extensive formation of ion-exchanged Pd2+ together with Pd sintering. These two types of Pd species appear to have lower CH4 oxidation activity and to be more sensitive to water deactivation compared to the well dispersed Pd particles observed on the LTA support prior to the hydrothermal aging. By contrast, Pd/Al2O3 was generally sensitive to water vapor no matter of the aging temperature. Although the aging caused extensive Pd sintering in Pd/Al2O3, only minor deterioration of the CH4 oxidation activity was seen. The results herein presented show that Pd/LTA is a promising CH4 oxidation catalyst, however Pd rearrangement at high temperatures (≥800 °C) is one remaining challenge.

scholarly journals Materializing efficient methanol oxidation via electron delocalization in nickel hydroxide nanoribbon

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaopeng Wang ◽  
Shibo Xi ◽  
Wee Siang Vincent Lee ◽  
Pengru Huang ◽  
Peng Cui ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Methanol Oxidation ◽  
Nickel Hydroxide ◽  
Direct Methanol Fuel Cell ◽  
Platinum Group Metal ◽  
Oxidation Catalyst ◽  
Oxidation Activity ◽  
Onset Potential ◽  
Direct Methanol ◽  
Methanol Fuel Cell

Abstract Achieving a functional and durable non-platinum group metal-based methanol oxidation catalyst is critical for a cost-effective direct methanol fuel cell. While Ni(OH)2 has been widely studied as methanol oxidation catalyst, the initial process of oxidizing Ni(OH)2 to NiOOH requires a high potential of 1.35 V vs. RHE. Such potential would be impractical since the theoretical potential of the cathodic oxygen reduction reaction is at 1.23 V. Here we show that a four-coordinated nickel atom is able to form charge-transfer orbitals through delocalization of electrons near the Fermi energy level. As such, our previously reported periodically arranged four-six-coordinated nickel hydroxide nanoribbon structure (NR-Ni(OH)2) is able to show remarkable methanol oxidation activity with an onset potential of 0.55 V vs. RHE and suggests the operability in direct methanol fuel cell configuration. Thus, this strategy offers a gateway towards the development of high performance and durable non-platinum direct methanol fuel cell.

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