Diode laser spectroscopy of the fundamental bands of , , , free radicals in the ground 2Σ+ electronic state
作者:M. Hübner、M. Castillo、P.B. Davies、J. Röpcke
DOI:10.1016/j.saa.2004.03.012
日期:2005.1
Rotationally resolved spectra of the fundamentalband of the CN free radical in four isotopic forms have been measured using tunable diode laser absorption spectroscopy. The source of the radical was a microwave discharge in a mixture of isotopically selected methane and nitrogen diluted with argon. The lines were measured to an accuracy of 5 x 10(-4) cm(-1) and fitted to the formula for the vibration
已经使用可调二极管激光吸收光谱法测量了四种同位素形式的CN自由基基带的旋转分辨光谱。自由基的来源是在用氩气稀释的同位素选择的甲烷和氮气的混合物中的微波放电。测得的线的精度为5 x 10(-4)cm(-1),并符合双原子分子振动旋转谱的公式,其中包括四次畸变常数。发现来自五个参数拟合的每个同位素异构体的谱带起源为12C14N:2042.42115(38)cm(-1),13C14N:2000.08479(23)cm(-1),12C15N:2011.25594(25)cm(- 1),13C15N:1968.22093(33)cm(-1),括号内给出的拟合度为标准偏差。由于自旋旋转相互作用,一些线显示出分解的分裂。将其平均以进行拟合。由upsilon = 0和四种同位素异构体的1个旋转常数得出的平均平衡核间距为1.171800(6)A,与微波光谱法确定的值非常吻合。
Promoting Effect of CeO<sub>2</sub> on the Catalytic Activity of Ba–Y<sub>2</sub>O<sub>3</sub> for Direct Decomposition of NO
作者:Yasuyuki Doi、Masaaki Haneda、Masakuni Ozawa
DOI:10.1246/bcsj.20140230
日期:2015.1.15
The effect of CeO2 additive on the catalytic performance of Ba–Y2O3 prepared by coprecipitaion for the direct decomposition of NO was investigated. Although Ba–Y2O3 effectively catalyzed NO decomposition, its activity was clearly increased by addition of CeO2. The optimum CeO2 content was 10 mol %. CO2-TPD measurement revealed that the addition of CeO2 into Ba–Y2O3 caused an increase in the CO2 desorption peak in the temperature range of 473 and 723 K derived from highly dispersed Ba species. The predominant role of CeO2 additive was suspected to effectively create the highly dispersed Ba species as catalytically active sites. Kinetic studies of NO decomposition on Ba–CeO2(10)–Y2O3 suggested that coexisting O2 suppresses the NO decomposition reaction by competitive adsorption. Isotopic transient kinetic analysis suggested a reaction pathway in which the surface NOx adspecies act as reaction intermediates for the formation of N2 in NO decomposition over Ba–CeO2–Y2O3. We concluded that CeO2 additive does not directly participate in the NO decomposition reaction as catalytically active species.
An Investigation of Promoter Effects in the Reduction of NO by H2 under Lean-Burn Conditions
作者:R Burch、M.D Coleman
DOI:10.1006/jcat.2002.3596
日期:2002.6
The reduction of NO by H2 has been investigatedunder lean conditions at temperatures representative of automotive “cold-start” conditions (<200°C) using MoO3- and Na2O-modified Pt/Al2O3 and Pt/SiO2 catalysts. It has been found that small additions of sodium significantly increase the NO conversion while larger loadings of sodium have a severe poisoning effect. However, in the presence of excess O2
使用MoO 3-和Na 2 O改性的Pt / Al 2 O 3和Pt / SiO在贫化条件下,在代表汽车“冷启动”条件(<200°C)的温度下,研究了H 2还原NO的情况。2种催化剂。已经发现,少量添加钠会显着提高NO转化率,而较大量的钠会产生严重的中毒作用。但是,在存在过量的O 2的情况下对于所有的Na含量,在低温下都没有观察到氮选择性的提高。实际上,已经发现在较高温度下有不利影响。钼作为促进剂的添加导致所有测试负载的NO转化率和氮选择性增加。最佳配方确定为1%Pt / 10%MoO 3 /0.27% Na 2 O / Al 2 O 3。对此进行了稳态同位素瞬态动力学(SSITK)实验,并使用标记的一氧化氮对“模型” Pt / MoO 3 / Na 2 O / SiO 2催化剂进行了实验,以估算导致N 2的物种的表面浓度, N 2O,保留NO。数据表明,对于Pt / Al 2 O 3和Pt
Mechanisms of the various nitric oxide reduction reactions on a platinum-rhodium (100) alloy single crystal surface
The reduction of nitric oxide with hydrogen was studied over a Pt0.25-Rh0.75(100) alloy surface used as a model catalyst for the automotive three-way catalyst. This paper emphasizes the mechanisms of the different reactions leading to the products dinitrogen, ammonia and nitrous oxide. For this purpose the reaction was studied under various experimental conditions including reactivity measurements
在用作汽车三元催化剂模型催化剂的 Pt0.25-Rh0.75(100) 合金表面上研究了用氢气还原一氧化氮。本文重点介绍了生成产品二氮、氨和一氧化二氮的不同反应的机理。为此目的,在各种实验条件下研究反应,包括在稳态条件下在 10-7 毫巴范围内和在 10 毫巴范围内随着 NO/H2 比率变化的反应性测量。此外,还研究了 NO 的热分解和 NO + NH3 的反应。使用 15NO 和 15NH3 是为了收集有关各种含氮产物形成反应机制的更多信息。通过使用低能电子衍射表征表面。俄歇电子能谱和热解吸能谱。从这些研究中得出的主要结论是:(a) 如果有足够的 N 吸附原子可用,则可以在使用的整个温度范围 (350-1300 K) 内通过 2 个 N 吸附原子的组合形成 N2。(b) 低于 600 K,N2 形成的主要贡献是通过 NOads + Nads → N2+ Oads。在较高温度下,主要机制是
Reactions of NH Radicals. I. Photolysis of HN<sub>3</sub>Vapor at 313 nm
作者:Sukeya Kodama
DOI:10.1246/bcsj.56.2348
日期:1983.8
Photolysis of HN3 vapor was studied at 313nm as a function of HN3 and Xe pressures, light intensity, and temperature. The photolysis of hydrazoic acid labeled with 15N was also studied. The quantum yields of N2, H2, and NH4N3 as a product were 4.85, 0.494, and 0.842 at 30 °C and 6.7 kPa of HN3, respectively. The mechanism for the main reactions was postulated as follows: HN3+hν(313nm)→N2+NH(a1Δ);