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Catalytic combustion of methane on substituted strontium ferrites

机译：取代锶铁氧体上甲烷的催化燃烧

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摘要

Sr-hexaferrites prepared by co-precipitation method and calcined at 700-1000 ℃ have been characterized by thermogravimetric and differential thermal analysis (TG-DTA), Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H_2-TPR), and Ar adsorption techniques. It has been shown that hexaferrite phase formed after calcination at 700 ℃ is amorphous and its crystallization occurs at 800 ℃. Specific surface area (S_(BET)) of the samples calcined at 700 ℃ is 30-60 m~2/g. Reduction in hydrogen proceeds in several steps, Fe(III) in the hexaferrite structure being practically reduced to Fe~0. Amount of hydrogen necessary for the reduction of the samples decrease in the order: SrMn_2Fe_(10)O_(19) > SrFe_(12)O_(19) > SrMn_6Fe_6O_(19) > SrMn_2Al_(10)O_(19). Surface composition of the ferrites differs from bulk. According to XPS data, the surface is enriched with strontium. Sr segregation is most probably explained by the formation of surface carbonates and hydroxocarbonates. The main components on the surface are in oxidized states: Mn~(3+) and Fe~(3+). Maximum activity in the methane oxidation is achieved for the SrMn_xFei_(12-x)O_(19) (0 < x< 2) catalysts. These samples are characterized by highest amount of the hexaferrite phase, which promotes change of oxidation state Mn(Fe)~(3+) <-> Mn(Fe)~(2+).
机译：通过热重分析和差热分析（​​TG-DTA），傅立叶变换红外光谱（FTIR），X射线光电子能谱（XPS），X-射线衍射（XRD），氢程序升温还原（H_2-TPR）和Ar吸附技术。结果表明，在700℃煅烧后形成的六铁素体相为非晶态，在800℃时发生结晶。 700℃煅烧的样品的比表面积（S_（BET））为30-60 m〜2 / g。氢气的还原过程分几个步骤进行，六价铁氧体结构中的Fe（III）实际上被还原为Fe〜0。还原样品所需的氢气量按以下顺序减少：SrMn_2Fe_（10）O_（19）> SrFe_（12）O_（19）> SrMn_6Fe_6O_（19）> SrMn_2Al_（10）O_（19）。铁氧体的表面成分与体积不同。根据XPS数据，表面富含锶。 Sr偏析最有可能是由表面碳酸盐和氢碳酸盐的形成引起的。表面上的主要成分处于氧化态：Mn〜（3+）和Fe〜（3+）。对于SrMn_xFei_（12-x）O_（19）（0

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  • 来源
    《Fuel》 |2011年第3期|p.1245-1256|共12页
  • 作者

    Marina V. Bukhtiyarova; Aleksandra S. Ivanova; Elena M. Slavinskaya; Lyudmila M. Plyasova; Vladimir A. Rogov; Vasily V. Kaichev; Aleksander S. Noskov;

  • 作者单位

    Boreskov Institute of Catalysis SB RAS, Pr. Akad. Lavrentieva, 5. 630090 Novosibirsk, Russia;

    Boreskov Institute of Catalysis SB RAS, Pr. Akad. Lavrentieva, 5. 630090 Novosibirsk, Russia;

    Boreskov Institute of Catalysis SB RAS, Pr. Akad. Lavrentieva, 5. 630090 Novosibirsk, Russia;

    Boreskov Institute of Catalysis SB RAS, Pr. Akad. Lavrentieva, 5. 630090 Novosibirsk, Russia;

    Boreskov Institute of Catalysis SB RAS, Pr. Akad. Lavrentieva, 5. 630090 Novosibirsk, Russia;

    Boreskov Institute of Catalysis SB RAS, Pr. Akad. Lavrentieva, 5. 630090 Novosibirsk, Russia;

    Boreskov Institute of Catalysis SB RAS, Pr. Akad. Lavrentieva, 5. 630090 Novosibirsk, Russia;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    hexaferrite; xrd; h_(2-)tpr; xps; methane oxidation;

    机译：六铁氧体;xrd;h_（2-）tpr;xps;甲烷氧化;

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