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141.
MoS2 是钼基加氢精制催化剂 [Co(Ni)Mo/γ Al2 O3]活性相的主要组份 ,其形态与结构对Co(Ni)Mo/γ Al2 O3的加氢脱硫 (HDS)、加氢脱氮 (HDN)活性的影响至关重要[1 ,2 ] .目前 ,人们通常使用的TPR方法虽可测定过渡金属硫化物的表面活性位 ,并可有效地区分位于催化剂活性相 (MoS2 slab)周边的硫物种 ,但对不同价态的钼尚无法鉴别[3] .本文制备了硫化态Mo/γ Al2 O3催化剂 ,以CO为探针分子 ,利用FTIR技术在液氮温度 (77K)下考察了催化剂的表面活性位 (钼物种 )及催化噻吩HDS的活性 .1 实… 相似文献
142.
石油馏份油加氢精制的核心是馏份油的加氢脱硫(HDS)和加氢脱氮(HDN)。目前用于基础研究与工业过程的加氢精制催化剂主要是负载型过渡金属硫化物[Co(Ni)Mo(W)/γ-AI2O3]^[1,2]。近年来的研究结果表明,在活性相中引入其它适宜种类的助剂组元有助于催化剂活性及产物选择性的改善^[3,4]。本文以Keggin型钼磷酸为硫化物前体活性相钼磷源、硝酸镍为镍源制成不同钼含量的负载型硫化态三组元催化剂(NiMoP/γ-AI2O3),并在TPR及连续流动固定床反应装置上考察了催化剂的氢还原性能及模型底物噻吩HDS反应活性。 相似文献
143.
硫化态三组元NiMoP/γ-Al2O3催化剂的TPR表征及噻吩HDS活性的研究 总被引:1,自引:0,他引:1
A series of sulfided tertiary NiMoP/γ-Al2O3 catalysts with different contents of MoO3 were prepared by using molybdophosphoric acid of Keggin structure(H3PMo12O40) and nickel nitrate as origins of active phase components of molybdenum, phosphorus and nickel, and characterized by TPR technique, with their HDS activity being investigated with thiophene as a model substrate. For the sulfided Mo-0 catalyst containing no nickel as promoter, the only hydrogen sulfide evolution peak Ⅰ is observed at 462 K and attributed to the hydrogenation of the so-called edge sulfur atoms chemisorbed on coordinatively unsaturated(cus) Mox+ sites on the MoS2 phase(MoS2 slab). With the introduction of nickel into the active phase of the sulfided Mo-0 catalyst and with the increase of the molybdenum loading, a new hydrogen sulfide evolution peak Ⅱ gradually develops at the low temperature side of the peak Ⅰ, at the same time accompanied by both the increase of the area ratio of the peak Ⅱ to the peak Ⅰ and the shift of the hydrogen sulfide evolution maximum rate to lower temperatures, which may imply the existence of two kinds of active centers related to molybdenum and nickel respectively and the synergic action between the two centers above. It should be noted that for the sulfided NiMoP/γ-Al2O3 catalysts, the thiophene HDS rate and the quantity of hydrogen sulfide evolved during TPR process increase monotonously with the atomic ratio of molybdenum to nickel in the form of [n(Ni)+n(Mo)]/n(Ni). On the basis of the results here, the conclusion may be reached that the two kinds of vacancies can be formed on the edge of Ni-Mo-S slab due to the loss of S during TPR process and vacancies or sites related to the H2S evolution peak II should be regarded as the mainly active reaction centers of thiophene HDS. 相似文献
144.
Pt/γ-Al2O3催化剂活性位的表征及其噻吩加氢脱硫催化活性 总被引:2,自引:0,他引:2
A series of Pt/γ Al 2O 3 catalysts with different content of Pt were characterized by using low temperature FT IR spectroscopy of adsorbed CO, while their catalytic activity for HDS was investigated with thiophene as a model substrate. On the basis of the experimental results, it has been obtained that the pseudo zero order rate of the thiophene HDS reaction is well linearly proportional to the total area of the two IR bands at 2?080 and 1?850 cm -1 of CO adsorbed on Pt/γ Al 2O 3, and that the Pt sites for CO adsorption may be the active centers for thiophene HDS reaction. 相似文献
145.
We propose a simple experimental scheme in which an unknown two-qubit state
is faithfully and deterministically teleported from Alice to Bob. The scheme
is constructed with four photons from parametric down conversion, linear
optical elements, and conventional photon detectors, all of which are
available in current technology. It is shown that the probability of
successful teleportation ideally reaches 100% based on single-photon
two-qubit-assisted Bell-state measurement, which can distinguish all
four Bell-states simultaneously via conventional photon detectors. By
generalizing the scheme, the teleportation of an unknown multi-qubit system
can also be realized. 相似文献
146.
The effects of trapped electrons on off-axis lower hybrid current drive (LHCD) in tokamaks are studied, A computer code for solving the Fokker-Planck equation in a toroidal geometry is developed and employed. The code is suitable for various auxiliary heating and current drive schemes in tokamak plasmas. The influence of the resonance regime on the current drive efficiency as well as the influence of trapped particle fraction on the current drive efficiency are emphasized. It is shown that, as an electrostatic force, the lower hybrid wave causes some of the trapped electrons to be untrapped and lose their energy, which can cut the LHCD efficiency by about 30%. The ITER scaling law is also used to estimate the trapped electron effects.[第一段] 相似文献
147.
本文采用静态水热合成法合成了一种非水溶性固体铜铝磷酸盐(CuAlPO).研究结果发现,CuAlPO是一种与六方二氧化硅(SiO2)晶体结构相同的新型铜铝磷盐,在温和反应条件下(30℃),CuAlPO具有较高的苯酚催化羟化反应活性. 相似文献
148.
偏高岭土合成4A沸石机理的研究 总被引:16,自引:0,他引:16
用XRD、FT IR、ICP、SEM、化学分析等方法研究了偏高岭土合成4A沸石的晶化反应机理。偏高岭土在NaOH溶液中部分溶解 ,且结构迅速转变为偏高岭土 * ,并伴有硅铝酸钠凝胶形成。偏高岭土 *也不断在碱液的作用下凝胶化 ,生成的凝胶进一步再转变为4A沸石 ,这两个过程在大部分反应时间里是同时进行的 ,直到晶化结束。液相参与凝胶、4A沸石前驱及晶核等的形成和4A沸石的成长。偏高岭土 *的凝胶化速度是整个晶化过程的决定步骤 ,该晶化过程极易形成大量聚晶。 相似文献
149.
用蒙脱土酸处理法制备洗用4A沸石过程中石英问题的探讨 总被引:8,自引:0,他引:8
目前我国洗涤剂用4A沸石实现半工业化的是采用以水玻璃、氢氧化铝为起始原料的全合成法[1],以该法生产沸石的产品质量较稳定,但生产成本较高。而以蒙脱土为原料的合成4A沸石,生产成本可以大大降低[2-4],但是蒙脱土中往往含有石英杂质,如果不设法去除,必将影响产品的纯度,使其质量指标(白度、粒度、钙离子交换量)难以达到洗涤剂行业标准[5],而且洗衣粉中含有石英也会磨损衣物。 本文将重点讨论石英这一问题,包括如何测定石英杂质含量和如何在用蒙脱土生产洗涤剂用4A沸石过程中去除石英杂质。1实验部分1.1实验样… 相似文献
150.