• Title, Summary, Keyword: catalytic oxidation

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Catalytic NiO Filter Supported on Carbon Fiber for Oxidation of Volatile Organic Compounds

  • Sim, Jong Ki;Seo, Hyun Ook;Jeong, Myung-Geun;Kim, Kwang-Dae;Kim, Young Dok;Lim, Dong Chan
    • Bulletin of the Korean Chemical Society
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    • v.34 no.7
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    • pp.2105-2110
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    • 2013
  • Carbon-fiber-supported NiO catalytic filters for oxidation of volatile organic compounds were prepared by electroless Ni-P plating and subsequent annealing processes. Surface structure and crystallinity of NiO film on carbon fiber could be modified by post-annealing at different temperatures (500 and $650^{\circ}C$). Catalytic thermal decompositions of toluene over these catalytic filters were investigated. $500^{\circ}C$-annealed sample showed a higher catalytic reactivity toward toluene decomposition than $650^{\circ}C$-annealed one under same conditions, despite of its lower surface area and toluene adsorption capacity. X-ray diffraction and X-ray photoelectron spectroscopy studies suggest that amorphous structures of NiO on $500^{\circ}C$-annealed catalyst caused the higher reactivity for oxidation of toluene than that of $650^{\circ}C$-annealed sample with a higher crystallinity.

Catalytic Oxidation of Toluene Using NiO Filter Supported on Carbon Fiber

  • Sim, Jong Ki;Seo, Hyun Ook;Jeong, Myung-Geun;Kim, Kwang-Dae;Nam, Jong Won;Kim, Young Dok;Lim, Dong Chan
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.217-217
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    • 2013
  • Carbon-fiber-supported NiO catalytic filters for oxidation of volatile organic compounds were prepared by electroless Ni-P plating and subsequent annealing processes. Surface structure and crystallinity of NiO film on carbon fiber could be modified by post-annealing at different temperatures (500 and $650^{\circ}C$. Catalytic thermal decompositions of toluene over these catalytic filters were investigated. $500^{\circ}C$ annealed sample showed a higher catalytic reactivity toward toluene decomposition than $650^{\circ}C$ annealed one under same conditions, despite of its lower surface area and toluene adsorption capacity. X-ray diffraction and X-ray photoelectron spectroscopy studies suggested that amorphous structures of NiO on $500^{\circ}C$ annealed catalyst caused the higher reactivity for oxidation of toluene than that of $650^{\circ}C$ annealed sample with a higher crystallinity.

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Support Effect of Catalytic Activity on 3-dimensional Au/Metal Oxide Nanocatalysts Synthesized by Arc Plasma Deposition

  • Jung, Chan Ho;Naik, B.;Kim, Sang Hoon;Park, Jeong Y.
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.140.2-140.2
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    • 2013
  • Strong metal-support interaction effect is an important issue in determining the catalytic activity for heterogeneous catalysis. In this work, we report the catalytic activity of $Au/TiO_2$, $Au/Al_2O_3$, and $Au/Al_2O_3-CeO_2$ nanocatalysts under CO oxidation fabricated by arc plasma deposition (APD), which is a facile dry process with no organic materials involved. These catalytic materials were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and $N_2$-physisorption. Catalytic activity of the materials has measured by CO oxidation using oxygen, as a model reaction, in a micro-flow reactor at atmospheric pressure. Using APD, the catalyst nanoparticles were well dispersed on metal oxide powder with an average particle size (3~10 nm). As for catalytic reactivity, the result shows $Au/Al_2O_3-CeO_2$ nanocatalyst has the highest catalytic activity among three samples in CO oxidation, and $Au/TiO_2$, and $Au/Al_2O_3$ in sequence. We discuss the effects of structure and metal-oxide interactions of the catalysts on catalytic activity.

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Electro-Catalytic Oxidation of Amoxicillin by Carbon Ceramic Electrode Modified with Copper Iodide

  • Karim-Nezhad, Ghasem;Pashazadeh, Ali;Pashazadeh, Sara
    • Journal of the Korean Chemical Society
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    • v.57 no.3
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    • pp.322-328
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    • 2013
  • Copper iodide was employed as a modifier for preparation of a new carbon ceramic electrode. For the first time, the catalytic oxidation of amoxicillin (AMX) was demonstrated by cyclic voltammetry, chronoamperometry and amperometry methods at the surface of this modified carbon ceramic electrode. The copper iodide modified sol-gel derived carbon ceramic (CIM-SGD-CC) electrode has very high catalytic ability for electrooxidation of amoxicillin. The catalytic oxidation peak current was linearly dependent on the amoxicillin concentration and the linearity range obtained was 100 to 1000 ${\mu}mol\;L^{-1}$ with a detection limit of 0.53 ${\mu}mol\;L^{-1}$. The diffusion coefficient ($D=(1.67{\pm}0.102){\times}10^{-3}\;cm^2\;s^{-1}$), and the kinetic parameter such as the electron transfer coefficient (${\alpha}$) and exchange current density ($j_0$) for the modified electrode were calculated. The advantages of the modified CCE are its good stability and reproducibility of surface renewal by simple polishing, excellent catalytic activity and simplicity of preparation.

Selective Production of Aromatic Aldehydes from Heavy Fraction of Bio-oil via Catalytic Oxidation

  • Li, Yan;Chang, Jie;Ouyang, Yong;Zheng, Xianwei
    • Bulletin of the Korean Chemical Society
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    • v.35 no.6
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    • pp.1654-1658
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    • 2014
  • High value-added aromatic aldehydes (e.g. vanillin and syringaldehyde) were produced from heavy fraction of bio-oil (HFBO) via catalytic oxidation. The concept is based on the use of metalloporphyin as catalyst and hydrogen peroxide ($H_2O_2$) as oxidant under alkaline condition. The biomimetic catalyst cobalt(II)-sulfonated tetraphenylporphyrin ($Co(TPPS_4)$) was prepared and characterized. It exhibited relative high activity in the catalytic oxidation of HFBO. 4.57 wt % vanillin and 1.58 wt % syringaldehyde were obtained from catalytic oxidation of HFBO, compared to 2.6 wt % vanillin and 0.86 wt % syringaldehyde without $Co(TPPS_4)$. Moreover, a possible mechanism of HFBO oxidation using $Co(TPPS_4)/H_2O_2$ was proposed by the research of model compounds. The results showed that this is a promising and environmentally friendly method for production of aromatic aldehydes from HFBO under $Co(TPPS_4)/H_2O_2$ system.

Catalytic Activity of $Nd_{1-x}Sr_xCoO_{3-y}$ on the Oxidation of Carbon Monoxide

  • Kim, Keu-Hong;Kim, Seong-Han;Lee, Dong-Hoon;Kim, Yoo-Young;Choi, Jae-Shi
    • Bulletin of the Korean Chemical Society
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    • v.12 no.1
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    • pp.35-39
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    • 1991
  • The catalytic activity of $Nd_{1-x}Sr_xCoO_{3-y}$, $0{\leq}x{\leq}0.75$ and $0.001{\leq}y{\leq}0.103$, on the oxidation of carbon monoxide has been investigated from the structure analyses of the catalysts by X-ray diffraction and infrared spectroscopy and the measurements of the oxidation and adsorption rates of carbon monoxide. The catalytic activity is found to be correlated with Sr substitution (x) and nonstoichiometry (y). The oxidation power of carbon monoxide increases continuously with increasing Sr substitution without oxygen, but increases with Sr substitution up to x = 0.25 and then is almost constant at larger x values up to x = 0.75 with oxygen. This change of catalytic activity is explained by the oxidation-reduction properties of the catalyst due to the variation of nonstoichiometry.

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Electrodeposited NiCu Alloy Catalysts for Glucose Oxidation

  • Lim, Ji-Eun;Ahn, Sang Hyun;Jang, Jong Hyun;Park, Hansoo;Kim, Soo-Kil
    • Bulletin of the Korean Chemical Society
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    • v.35 no.7
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    • pp.2019-2024
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    • 2014
  • NiCu alloys have been suggested as potential candidates for catalysts in glucose oxidation. In this study, NiCu alloys with different compositions were prepared on a glassy carbon substrate by changing the electrodeposition potential to examine the effect of Ni/Cu ratios in alloys on catalytic activity toward glucose oxidation. Cyclic voltammetry and chronoamperometry showed that NiCu alloys had higher catalytic activity than pure Ni and Cu catalysts. Especially, Ni59Cu41 had superior catalytic activity, which was about twice that of Ni at a given oxidation potential. X-ray analyses showed that the oxidation state of Ni in NiCu alloys was increased with the content of Cu by lattice expansion. Ni components in alloys with higher oxidation state were more effective in the oxidation of glucose.

Support Effect of Arc Plasma Deposited Pt Nanoparticles/TiO2 Substrate on Catalytic Activity of CO Oxidation

  • Qadir, Kamran;Kim, Sang Hoon;Kim, Sun Mi;Ha, Heonphil;Park, Jeong Young
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.261-261
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    • 2013
  • The smart design of nanocatalysts can improve the catalytic activity of transition metals on reducible oxide supports, such as titania, via strong metal-support interactions. In this work, we investigatedtwo-dimensional Pt nanoparticle/titania catalytic systems under the CO oxidation reaction. Arc plasma deposition (APD) and metal impregnation techniques were employed to achieve Pt nanoparticle deposition on titania supports, which were prepared by multitarget sputtering and sol-gel techniques. APD Pt nanoparticles with an average size of 2.7 nm were deposited on sputtered and sol-gel-prepared titania films to assess the role of the titania support on the catalytic activity of Pt under CO oxidation. In order to study the nature of the dispersed metallic phase and its effect on the activity of the catalytic CO oxidation reaction, Pt nanoparticles were deposited in varying surface coverages on sputtered titania films using arc plasma deposition. Our results show an enhanced activity of Pt nanoparticles when the nanoparticle/titania interfaces are exposed. APD Pt shows superior catalytic activity under CO oxidation, as compared to impregnated Pt nanoparticles, due to the catalytically active nature of the mild surface oxidation and the active Pt metal, suggesting that APD can be used for large-scale synthesis of active metal nanocatalysts.

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Investigation of Catalytic Activity Through Controlling Its Size and Composition of RhPt Bimetallic Nanoparticles (RhPt 이종금속 나노입자의 크기 및 조성 제어를 통한 촉매 활성도에 관한 연구)

  • Park, Jeong-Young;Kim, Sun-Mi
    • Journal of Korean Powder Metallurgy Institute
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    • v.18 no.6
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    • pp.538-545
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    • 2011
  • This study shows that catalytic activity of bimetallic RhPt nanoparticle arrays under CO oxidation can be tuned by varying the size and composition of nanoparticles. The tuning of size of RhPt nanoparticles was achieved by changing concentration of rhodium and platinum precursors in one-step polyol synthesis. Two-dimensional RhPt bimetallic nanoparticle arrays in different size and composition were prepared through Langmuir-Blodgett thin film technique. CO oxidation was carried out on these two-dimensional nanoparticle arrays, revealing higher activity on the smaller nanoparticles compared to the bigger nanoparticles. X-ray photoelectron spectroscopy (XPS) results indicate the preferential surface segregation of Rh compared to Pt on the smaller nanoparticles, which is consistent with the thermodynamic analysis. Because the catalytic activity is associated with differences in the rates of $O_2$ dissociative adsorption between Pt and Rh, this paper suppose that the surface segregation of Rh on the smaller bimetallic nanoparticles is responsible for the higher catalytic activity in CO oxidation. This result suggests a control mechanism of catalytic activity via synthetic approaches of colloid nanoparticles, with possible application in rational design of nanocatalysts.

Homogeneous and Catalytic Methanol Synthesis by Partial Oxidation of Methane (메탄의 균일 및 접촉부분산화에 의한 메탄올 합성)

  • Hahm, Hyun-Sik;Choi, Woo-Jin;Hwang, Jae-Young;Ahn, Sung-Hwan;Kim, Myung-Soo;Park, Hong-Soo
    • Journal of the Korean Applied Science and Technology
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    • v.22 no.1
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    • pp.56-61
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    • 2005
  • Methanol was synthesized by homogeneous and catalytic reactions of partial oxidation of methane. The effect of pressure, temperature and oxygen concentration on methanol synthesis was investigated. The catalyst used was Bi-Cs-Mg-Cu-Mo mixed oxide. The partial oxidation reaction was carried out in a fixed bed reactor at 20${\sim}$46 bar and $450{\sim}480^{\circ}C$ and oxygen concentration of 5.3${\sim}$7.7mol%. The results were compared with results of homogeneous reaction performed at the same conditions. Methane conversions of the homogeneous and catalytic reactions increased with temperature. Methanol selectivity of the homogeneous reaction decreased with increasing temperature. However, the methanol selectivity of catalytic reaction increased with temperature. For both homogeneous and catalytic reactions, the methane conversions were around 5%. This may be due to the low oxygen concentration. Methanol selectivity of the catalytic reaction was higher than that of homogeneous one.