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1.
通过浸渍法制备了Fe和Cu含量比不同的系列Fe-Cu/ZSM-5催化剂,利用XRD、H2-TPR、NH3-TPD和原位DRIFTS等技术对催化剂进行了表征,并对其NH3-SCR脱硝性能进行了研究。结果表明,双金属改性的Fe-Cu/ZSM-5催化剂活性温度窗口拓宽,其中,Fe-Cu/ZSM-5 1∶4催化剂脱硝性能优异,250-450℃下脱硝效率均超过90%,335℃时脱硝效率达到最大值96.46%。铜和铁物种能以无定型氧化物良好分散于载体表面,双金属负载改性催化剂保留了ZSM-5的晶体结构。Fe-Cu/ZSM-5 1∶4催化剂具备丰富的酸性位、良好的氧化还原性能,一定温度条件下NH3-SCR反应过程中同时存在E-R机理和L-H机理,且E-R机理反应起始温度低于L-H机理;200℃为催化脱硝反应的起活温度。 相似文献
2.
A tandem quadrupole mass spectrometer is used to study the charge transfer reactions NH3+ + NO and NO+ + NH3 over a collision energy range 1.5–13 eV. The vibrational state of the reagent ions is selected by resonance-enhanced multiphoton ionization. For the 0.9 eV exothermic process NH3+ + NO → NH3 + NO+ excitation of the v2 umbrella bending mode (v2 = 0–12) causes no marked change in the charge transfer cross section, while in the reverse process NO+ + NH3 → NO + NH3+ excitation of the NO+ vibration (v = 0–6) strongly enhanced the charge transfer cross section. 相似文献
3.
V. A. Zazhigalov V. M. Belousov N. D. Konovalova Yu. N. Merkureva A. I. Pyatnitskaya G. A. Komashko 《Reaction Kinetics and Catalysis Letters》1989,38(1):147-152
It has been established that NH3 and SO2 adsorption on the surface of V–P–O catalysts at reaction temperatures modifies its acid-base properties, which changes its activity and selectivity.
, NH3 SO2 V–P–O -C4H10, - .相似文献
4.
Adsorption and coadsorption of NH3 and NO on alumina-supported manganese oxide catalyst prepared from manganese formate precursor has been studied by means
of FTIR spectroscopy.
Dedicated to the 65th birthday of Prof. Dr. H.D. Lutz (University of Siegen, Germany) 相似文献
5.
碱金属沉积对Mn-Ce/TiO低温SCR催化剂性能影响 《燃料化学学报》2018,46(12):1513-1519
采用溶胶凝胶法制备了Mn-Ce/TiO_2低温SCR催化剂,考察了碱金属浓度与种类对催化剂活性的影响,探究了不同反应条件下钠盐沉积对活性保留分率的影响,利用SEM、BET、XRD和FT-IR对催化剂碱金属中毒原因进行了分析。结果表明,碱金属毒化后催化剂脱硝活性下降,钾中毒催化剂失活程度高于钠中毒的催化剂,2%钾中毒催化剂在160℃时NO去除率为62.0%,较新鲜催化剂下降29.2%。这主要因为碱金属毒化造成催化剂比表面积明显减小,且催化剂载体锐钛矿型TiO_2部分转化为金红石型,BET和SEM表征均说明碱金属沉积堵塞了催化剂表面的微孔。碱金属对Mn-Ce/TiO_2催化剂活性保留分率的影响表明,催化剂的颗粒粒径对其活性保留分率影响不大,碱金属含量减小、温度升高,Mn-Ce/TiO_2催化剂的活性保留分率增加,Na_2SO_4和NaCl对Mn-Ce/TiO_2催化剂的脱硝活性抑制作用大于KNO_3。 相似文献
6.
利用共沉淀法制备了铁铈复合氧化物催化剂,在积分实验系统上考察了NO初始浓度、NH3/NO比及O2浓度对其SCR脱硝活性的影响;并借助微分系统探讨了其SCR脱硝的催化反应动力学,构建了铁铈复合氧化物催化剂的催化脱硝反应动力学模型.实验结果表明,NO初始浓度越高,每克催化剂的NO转化率越高;随着NH3/NO比的增加,NO转化率先迅速增加后趋势减缓,最终趋于稳定;O2在NH3-SCR反应中起着重要的作用;在175~225 ℃下,Fe0.95Ce0.05Oz催化剂的NO和NH3反应级数分别为1级和0级,O2的反应级数接近0.5级,该反应的表观活化能为42.6 kJ/mol. 相似文献
7.
采用浸渍法制备了一系列不同铜含量的Cu/SAPO-34催化剂,考察了该系列催化剂上NH_3选择性催化氧化反应性能(NH_3-SCO)。实验结果表明,10%-Cu/SAPO-34催化剂在300℃温度下具有100%的NH_3去除率,且其氮气选择性大于90%。与此同时,通过XRD、BET、UV-vis、H_2-TPR和XPS等表征分析结果表明,高度分散的CuO是Cu/SAPO-34催化剂的主要活性组分。对10%-Cu/SAPO-34催化剂进行水热处理后,催化剂低温活性明显提高,催化剂的N_2选择性在325℃急剧下降。这是由于水热处理导致一定数量的铜物种发生迁移并且形成了更稳定的铜物种引起。SAPO-34的骨架结构遭到一定程度的破坏。 相似文献
8.
非晶态CeO_2@TiO_2催化剂的结构、性质及其选择催化还原脱硝性能 总被引:1,自引:0,他引:1
非晶态CeO@TiO催化剂的结构性质及其选择催化还原脱硝性能 《燃料化学学报》2016,44(8):954-960
采用自发沉积法制备了非晶态Ce O_2@Ti O_2催化剂,通过XRD、Raman光谱、TEM、N_2吸附、H_2-TPR、NH_3-TPD及FTIR等手段表征了催化剂结构和表面性质,研究了Ce O_2@Ti O_2在选择催化还原脱NO反应中的催化性能。结果表明,非晶态Ce O_2@Ti O_2催化剂中Ce与Ti间存在很强的相互作用,能够在原子水平上相互结合,表现出与晶态结构截然不同的还原特性,具备更强的氧化还原能力。同时,与浸渍法制备的Ce O_2/Ti O_2相比,Ce O_2@Ti O_2还具有更大的比表面积和更强的表面酸性,因而具有更加优异的脱硝性能。在175℃下NO转化率即达到80%以上,在200-400℃脱硝率稳定在96.0%-99.4%;同时,H_2O和SO_2的阶跃应答实验表明,Ce O_2@Ti O_2具有很强的抗水和抗SO_2毒化能力。 相似文献
9.
制备了一种新的氟掺杂氧化钒/氧化钛催化剂,探讨了掺杂模式、制备方法对低温SCR活性的影响.结果显示,在120~240℃反应温度下,由溶胶法制得的氟掺杂于钒(F-V)模式下的催化活性最佳,通过与未掺杂催化剂(COM)对比可知,在210℃时,氟掺杂催化剂的活性提高了35%,并于240℃时NO的脱除率达到了98.6%.通过X射线衍射试验(XRD)、透射电子显微镜(TEM)、比表面积测试(BET)、光电子能谱分析(XPS)以及H_2程序升温还原(H_2-TPR)等表征技术显示氟掺杂引起催化剂SCR活性提升主要与催化剂活性成分的良好分散性、粒子尺寸减小、比表面积及孔容增大、更强的氧化还原能力有关.另外,通过试验研究表明,氟掺杂催化剂不仅提升了SCR活性,拓宽了活性温度范围,而且还增强了抗硫与抗水性能. 相似文献
10.
Ce-Al2O3 catalysts prepared by co-precipitation are investigated both in NO oxidation by O2 and in selective catalytic reduction of NO by C2H2(C 2 H 2-SCR).It is found that C2H2-SCR is initiated and controlled by NO oxidation to NO 2 over Al2O3.Ce loading on Al2O3 is almost inactive for NO oxidation below 350 C,since NO2 strongly adsorbs on cerium oxide,leading to the active sites being blocked,which was characterized by temperature-programmed desorption of NO and NO 2 and Fourier transform infrared spectroscopy after NO+O 2 coadsorption over the samples.However,in the case of C2H2-SCR,Ce loading on Al 2 O 3 significantly improves the reaction by accelerating the NO oxidation step in the temperature range of 250-450 C,since the nitrate species produced by NO 2 adsorption is an active intermediate required by C2H 2-SCR. 相似文献
11.
Laser induced fluorescence from the Ã2A1 state of the NH2 radical, obtained by different methods, has been observed with a tunable cw dye laser as excitation source. Using pulsed photolysis of NH3 to produce NH2, the fluorescence technique has been employed in a first gas kinetic application to measure the rate constant of the aeronomically interesting NH2 + NO reaction at 298 K. A value of (2.1 ± 0.2) × 10-11 cm3 molecule-1 s-1 has been obtained. 相似文献
12.
The kinetics of the oxidation of ascorbic acid by [(NH3)5RuORu(NH3)4ORu(NH3)5]7+ has been studied by the stopped-flow method. The activation parameters have been calculated and a possible mechanism is suggested.
[(NH3)5RuORu(NH3)4ORu·(NH3)5]7+ . .相似文献
13.
The Mössbauer spectra of 57Fe doped NH4MnCl3 reveal that this compound undergoes a crystallographic phase transition at 258°K and becomes magnetic at 105°K. No crystallographic transition appeared either in NH4FeCl3 or in 57Fe:NH4CoCl3; the latter orders magnetically around 27°K. 相似文献
14.
Adsorption and coadsorption of NH3 and NO on copper-on-alumina catalysts prepared from formate precursors by calcination at 670 and 870 K was studied by means
of FTIR spectroscopy. It has been established that the sample prepared at lower temperature exhibits a higher activity with
respect to NO reduction with ammonia.
Dedicated to the 65th birthday of Prof. Dr. Chr. Balarew, Bulgarian Academy of Sciences, Sofia, Bulgaria 相似文献
15.
原位聚合MnO/PoPD@PPS复合滤料及其NH-SCR脱硝性能研究 《燃料化学学报》2017,45(12):1514-1521
在聚苯硫醚(PPS)滤料表面包覆一层二氧化锰/聚邻苯二胺(PoPD)复合物。利用π-π共轭效应,将邻苯二胺(OPD)单体均匀吸附在PPS纤维表面,然后通过高锰酸钾溶液使邻苯二胺氧化聚合,在纤维表面原位生成聚邻苯二胺包覆层,同时高锰酸钾被还原成MnO_2催化剂,插入到聚邻苯二胺基体中。通过原位聚合生成的MnO_2/PoPD复合物与PPS滤料间有很强的黏结性,使得催化剂和滤料能牢固地结合在一起。该复合滤料制备方法简单,实验条件温和,对滤料本身性能没有损伤,通过FESEM、XPS、XRD、FT-IR、脱硝活性测试等对其结构和性能进行了研究。脱硝测试结果表明,KMnO4/PPS质量比为1∶1时,复合滤料在80-180℃下脱硝率可达36%-94%,10 h的催化剂稳定性测试中,其脱硝率在160℃下仍保持在88%;Mn 2p的XPS谱图证实复合滤料上催化剂为MnO_2;复合滤料的XRD谱图表明MnO_2为非晶结构;从FESEM照片可以看出,MnO_2催化剂在PPS滤料上分散均匀。 相似文献
16.
17.
SO存在条件下M/REY催化剂NH选择性还原NO性能研究 《燃料化学学报》2013,41(10):1241-1247
采用浸渍法制备了以REY为载体负载金属氧化物催化剂。采用XRD、NH3-TPD、NO-TPD、H2-TPR和XPS对催化剂进行表征,并在固定床微型反应器上评价SO2存在条件下催化剂在NH3选择还原NO反应中的活性。实验结果表明,活性组分种类及负载量均影响催化剂性能,Cu(3)/REY催化剂在NH3选择还原NO反应中表现出较好的低温活性,在SO2存在条件下,254~390℃时NO的转化率大于95%。催化剂表征结果显示,Cu(3)/REY催化剂的催化活性与其良好的氧化还原性和对NO的吸脱附性能相关。 相似文献
18.
A normal coordinate analysis for the AlCl3 · NH3 complex is performed. Calculations for a hypothetical complex with a planar AlCl3 ligand are included. A deviation from planarity is found in the realistic complex. Force fields for free NH3 and AlCl3 molecules are employed in the construction of an initial approximate force field. The theory of kinematic coupling is used to study the frequency shifts from free to complexed ligands. A final force field is developed so as to reproduce exactly a set of observed frequencies from the literature. Calculations on mean amplitudes and perpendicular amplitude correction coefficients are reported. 相似文献
19.
使用溶胶-凝胶法制备了LaCoO3催化剂,采用XRD、BET和XPS等方式对催化剂进行了表征,考察了该催化剂制备过程中煅烧温度、表面活性剂PEG-6000和PEG-20000含量对其H2S选择氧化制硫磺反应催化活性的影响。结果表明,表面活性剂PEG-6000及PEG-20000的添加能明显提高LaCoO3的催化活性。0.02 mol La(NO3)3+0.02mol Co(NO3)2溶液中添加0.30 g PEG-20000、煅烧温度为650℃时所制备的LaCoO3催化活性最好;在最佳反应温度260℃下,H2S的转化率达到96.10%,硫选择性为93.77%。 相似文献