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1.
Ni/Al2O3和Ni/La2O3催化剂上低温乙醇水蒸气重整制氢 总被引:14,自引:0,他引:14
采用浸渍、热分解和氢还原等步骤制备了两种纳米晶载体催化剂Ni/Al2O3和Ni/La2O3,应用X射线衍射、X射线光电子能谱、N2吸附和扫描电镜对催化剂的体相和表面结构进行了测定,采用固定床反应器考察了催化剂对乙醇水蒸气重整制氢反应的催化性能. 实验结果表明, 15.3%Ni/La2O3催化剂对乙醇的低温水蒸气重整反应表现出较高的催化活性和稳定性. 250 ℃时乙醇的转化率已达到80.7%,氢气的选择性为49.5%; 330 ℃时乙醇的转化率达到100%,氢气的选择性可达54.3%. 16.1%Ni/Al2O3催化剂对低温乙醇水蒸气重整反应的催化活性较低. 相似文献
2.
Mo助剂含量对Mo-Ni2P/SBA-15/堇青石整体式催化剂加氢脱硫性能的影响 总被引:3,自引:0,他引:3
采用共浸渍法制备了 P/Ni 摩尔比为 2 的 Ni2P/SBA-15, 再通过二次浸渍引入助剂 Mo 制得 Mo-Ni2P/SBA-15, 将它调制成活性胶后均匀涂敷于预处理后的载体表面, 干燥焙烧后在氢气流中采用程序升温还原法, 制备了一系列 Mo-Ni2P/SBA-15/堇青石整体式催化剂. 采用 X 射线衍射、N2 吸附-脱附和 X 射线光电子能谱对催化剂结构进行了表征, 以二苯并噻吩为模型含硫化合物, 考察了催化剂的加氢脱硫性能. 结果表明, Mo 的加入增大了催化剂的比表面积, 在催化剂表面形成了 MoNiP2, 且 Ni2P 为主要活性物相. Mo 在催化剂表面主要以 Mo6+和 Moδ+形式存在; 当 w(Mo) = 4.2% 时, n(Mo)/n(Ni+Mo) = 0.18 的整体式催化剂上二苯并噻吩的转化率最高, 且在较低反应温度时以直接脱硫机理为主, 而较高反应温度时以加氢脱硫机理为主. 相似文献
3.
采用程序升温反应法制备了钝化态、还原钝化态和新鲜态Mo2C/γ-Al2O3催化剂,结合原位红外光谱表征技术和反应性能评价,考察、比较了三种催化剂苯加氢反应活性.原位红外光谱结果表明,新鲜态Mo2C/γ-Al2O3催化剂在室温就显示了较好的苯加氢反应活性,表现了类贵金属的催化活性.CO吸附在反应前后新鲜态Mo2C/γ-Al2O3催化剂上的对比结果表明,低价态的Mo位(Moδ+(0δ2))是苯加氢反应活性中心.三种催化剂的反应活性结果表明,新鲜态Mo2C/γ-Al2O3催化剂反应活性最好,催化剂寿命最长,失活之后在500°C下H2处理即可恢复原有活性. 相似文献
4.
CO2氧化异丁烷制异丁烯用Pd/V2O5-SiO2催化剂 总被引:4,自引:0,他引:4
利用表面化学反应改性法制备了不同V2O5负载量的V2O5-SiO2表面复合物载体,进而采用等体积浸渍法制备了负载型Pd催化剂. 用N2吸附、 X射线衍射、透射电镜、 X射线光电子能谱、程序升温脱附、化学吸附-红外光谱和微反技术对系列Pd/V2O5-SiO2催化剂的比表面积、晶相结构、价态、异丁烷的化学吸附性能和CO2部分氧化异丁烷制异丁烯的催化性能进行了研究. 结果表明, Pd/V2O5-SiO2催化剂中的钒以V5+形式存在, V5+在催化剂表面形成活性位V=O, 其中 V=O 晶格氧与 i-C4H10分子的-CH3 和-CH 中的H产生化学吸附作用; 催化剂中金属Pd与V4+协同作用使CO2在催化剂上产生了卧式吸附态; 晶格氧参加了催化氧化反应,催化剂中 V5+←→V4+ 的变化构成了催化反应的氧化还原过程. 在525 ℃, CO2/i-C4H10体积比为1和空速为 1200 h-1的条件下,以Pd/25%V2O5-SiO2为催化剂时异丁烷转化率为22.8%, 异丁烯选择性为89.1%. 相似文献
5.
考察了CeO2修饰及未修饰的Ni/Mo/SBA-15催化剂在CH4-CO2重整上的催化性能并采用N2吸脱附、CO2程序升温脱附、H2程序升温还原、傅里叶红外光谱、X射线衍射、扫描电子显微镜和X射线光电子能谱对催化剂进行了表征.结果表明,在常压,800oC条件下,经过100h在线评价后,Ni/Mo/SBA-15和CeO2/Ni/Mo/SBA-15催化剂仍具有高的反应活性和规整的六方介孔结构,其中CeO2修饰的CeO2/Ni/Mo/SBA-15催化剂表面没有积炭形成,表明CeO2的加入促进了Ni物种在SBA-15介孔分子筛表面的分散,从而阻止了Ce/Ni/Mo/SBA-15催化剂上Ni的烧结和积炭. 相似文献
6.
水凝胶法制备Ni/ZrO2催化剂及催化CO2加氢甲烷化性能 总被引:1,自引:0,他引:1
采用水凝胶法制备出一系列Ni/ZrO2催化剂,使用X射线衍射(XRD),比表面积(BET)测试,透射电子显微镜(TEM)和氢气程序升温还原(H2-TPR)对其结构进行了表征,并考察了在CO2加氢甲烷化反应中的催化活性.研究结果表明,经过450℃焙烧的催化剂中ZrO2呈无定形结构,NiO均匀分散在ZrO2表面上;在400℃时H2还原过程中,部分无定形ZrO2转变为四方晶相结构并使Ni再次分散,Ni与ZrO2之间的电子作用抑制了Ni晶粒的生长和ZrO2晶型的转变;与无定形ZrO2和四方相ZrO2产生电子作用的NiO对催化剂活性起决定性作用,当Ni/Zr摩尔比为0.707时,催化剂活性最高.在H2/CO2体积比为4,空速为1×104h-1,压力为0.5 MPa,反应温度为200℃时,CO2转化率达到27%以上,当反应温度上升至280~320℃时,CO2转化率达到99%以上,CH4选择性大于92%. 相似文献
7.
采用程序升温氮化法制备了Mo2N/SiO2,在此基础上负载Ni盐,制备了Ni-Mo2N/SiO2复合纳米催化剂,并考察了催化剂对四氢萘加氢的催化活性.结果表明,与Ni2Mo3N/SiO2及Ni/SiO2催化剂相比,Ni-Mo2N/SiO2复合催化剂具有较高的催化活性.采用"分离床"方法研究了Ni和Mo2N对四氢萘加氢活性的影响.通过X射线粉末衍射、透射电镜、氢吸附、元素分析和比表面积测定等技术对Ni-Mo2N/SiO2催化剂进行了表征.结果表明,与Ni/SiO2催化剂相比,Ni-Mo2N/SiO2复合催化剂中Ni的分散度并未提高;催化活性的提高归因于Ni与Mo2N在四氢萘加氢中的协同作用.氮化物的引入增加了芳烃吸附活性位的数目.提出了四氢萘在Ni-Mo2N/SiO2催化剂上的可能加氢机理. 相似文献
8.
9.
ACo_2O_4/HZSM-5催化剂上N_2O的直接分解 总被引:1,自引:0,他引:1
分别采用柠檬酸络合燃烧法和低温络合浸渍法制备尖晶石型复合金属氧化物催化剂ACo2O4(A=Mg,Ni,Zn)和分子筛负载尖晶石型复合金属氧化物催化剂ACo2O4/HZSM-5(A=Mg,Fe,Ni,Cu,Zn,Zr,La).采用X射线衍射(XRD)、氨程序升温脱附(NH3-TPD)、扫描电子显微镜(SEM)和X射线能谱(EDS)等手段对催化剂进行表征,并在固定床微型反应器中评价其催化分解N2O活性.实验结果表明,A位离子种类影响ACo2O4/HZSM-5催化剂活性,以Ni、Fe、Zr或La为A位离子时,催化剂的活性较好,N2O分解温度低.ACo2O4/HZSM-5催化剂的活性高于ACo2O4尖晶石型复合氧化物,一方面是ACo2O4在分子筛HZSM-5载体上高度分散,使其以超细颗粒形态存在,另一方面ACo2O4/HZSM-5催化剂具有适宜的酸性,可提高催化剂的活性. 相似文献
10.
Ni/ZrO2-Al2O3制备表征及催化性能的研究 总被引:1,自引:0,他引:1
本文采用浸渍沉淀法制备了不同配比的ZrO2-Al2O3复合载体。并通过浸渍法制备Ni/ZrO2-Al2O3催化剂,以苯加氢制环己烷反应为探针,考察了ZrO2与Al2O3的配比对Ni催化剂催化加氢性能的影响;采用X射线衍射(XRD)、程序升温还原(TPR)、程序升温脱附(TPD)等技术考察复合载体对Ni催化剂的体相结构、还原性能以及表面吸附性能的影响。研究结果表明,ZrO2质量分数为20%的复合载体所负载的Ni催化剂有很好的加氢活性,优于单组分载体负载的Ni催化剂;采用浸渍沉淀法制备的ZrO2-Al2O3复合载体中ZrO2以非晶态形式存在,这是由于Al2O3的存在影响了ZrO2的内部结构;该载体负载的Ni催化剂较其他催化剂更容易被还原,吸附中心数量增加。 相似文献
11.
Hot atom chemical reaction by50Cr/n, /51Cr and52Cr/, n/51Cr reactions, and recoil implantation reaction by51V/p, n/51Cr reaction were investigated using geometrical isomers /mer and fac/ of tris/benzoylacetonato/ chromium/III/ /Cr/ba/3/. The production of counter isomer was observed for both mer- and fac-targets, although the yield of labelled parent isomer was larger. The observed mer/fac yield ratio suggests that the main formation mechanism of51Cr/ba/3 is the reaction of ba– and Cr/ba/
2
+
which has the same geometrical configuration of target complex, and the substitution reaction of central metal atom by recoil51Cr. Furthermore, implantation gave rise to a much higher yield of labelled Cr/ba/3 compared to the case of in situ nuclear recoils. 相似文献
12.
D. Bhatta P. G. Dalai S. R. Mohanty 《Journal of Radioanalytical and Nuclear Chemistry》1984,85(6):357-362
The annealing of chemical radiation damage in 1 MGy60Co gamma irradiated tris-/ethylenediamine/cobalt/III/ nitrate has been studied at different temperatures between 100 and 150 °C. The nitrate moiety suffers very little decomposition and the damage is only partially removed under these conditions. The recovery rate is rapid in the initial period/up to 1 h/ and remains almost constant on further heating to 10 h. 相似文献
13.
利用溶胶-凝胶分配理论对氢键溶液的模型体系进行研究, 给出了凝胶点后氢键网络中各结构参数的计算方案, 并进行相应的数值计算. 结果表明, 因受体基团本身的性质及两类质子受体基团的数量比不同, 受体基团的竞争作用对网络结构有明显影响, 这提供了控制氢键网络结构特征的可能方法. 相似文献
14.
The separation of iron/III/ from manganese/II/ by solvent extraction from hydrochloric acid to the chloroform solution of acetylacetone was applied to the analysis of basalts. The results after single and double separation of iron/III/ from manganese/II/ in basalts are presented. 相似文献
15.
P. S. Tjioe J. J. Kroon P. Lelieveld W. J. F. Van der Vijgh 《Journal of Radioanalytical and Nuclear Chemistry》1986,104(2):103-113
Platinum and eleven other trace elements were determined by radiochemical neutron activation analysis in tissues of healthy rats and dogs treated with the anti-cancer drug carboplatin. In rats the levels of the trace elements were not much influenced; in the kidney only the Co and the Sb levels were decreased and in the liver only the Mo level was increased. A parallel tendency in the Co and Mo metabolism was seen in dogs. Carboplatin treatment tends to reduce the Cd, Co and Fe levels in metabolic active organs, kidney, liver, spleen and/or pancreas of the dog. 相似文献
16.
以FT-IR方法研究了水/C12-EOx-C12•2Br/正己醇/正庚烷形成的W/O微乳中水的状态. 结果表明, 其中的水存在4种状态, 分别为阳离子头基结合水、反离子结合水、类似本体的水以及束缚在微乳栅栏层中的水. 由解卷积技术分解FT-IR谱图, 进而获得每个表面活性剂分子对应于这4种状态水分子的数目nN+, nBr-, nb和nf. 随着水含量(W0)增加, nb急剧增大, nN+少许上升, 而nf和nBr-维持不变, 这说明微乳水核逐渐长大, 且在所考察W0范围内, 表面活性剂头基解离度保持不变. 相似文献
17.
The recoil reactions of technetium produced by100Ru/γ, p/99mTc reaction were studied in γ-irradiated mer- and fac-Ru/ba/3 targets. Yields of mer- and fac-Tc/ba/3 were determined by column chromatographic separation developed in our previous work. In the initial recoil reaction yields mer-form of Tc/ba/3 was much more abundant than fac-form in the mer-Ru/ba/3, but the reverse held good in the fac-Ru/ba/3 showing selectivity in recoil replacement reactions in geometrical isomers. In the annealing reactions, however, such selectivity disappeared and the fac/mer ratio for the annealed portions could be explained by the following mixed mechanisms of ligand incorporation. $$\begin{gathered} Tc/ba/_2^ + + ba^ - \to Tc/ba/_3 \hfill \\ Tc/ba/^{2 + } orTc^{3 + } + xba \to Tc/ba/_3 \hfill \\ /x = 2or3/. \hfill \\ \end{gathered} $$ 相似文献
18.
H. J. MacCordick J.-C. Hubert J. J. Schleiffer 《Journal of Radioanalytical and Nuclear Chemistry》1989,135(5):349-357
The absorption effect of 5% w/w non-proliferative cell suspensions of Mycobacterium smegmatis on labelled solutions of Eu3+ ions, both alone and in admixtures with Am3+, Co2+ and Cs+, was studied at pH 1.0 as a function of time and cationic concentration. For 10 M concentrations of Eu, Co and Cs, selective adsorption of the trivalent lanthanide and actinide ions was practically quantitative after 90 min; no significant adsorption was observed for cobalt and cesium ions. Column adsorption measurements with the mycobacterial biomass showed that desorption of the M3+ ions did not occur at less than 2M HCl and remained incomplete even at higher acidities. 相似文献
19.
V. N. Serezhkin L. B. Serezhkina D. V. Pushkin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(5):826-834
Nonvalent interactions in crystals of compounds of the composition C
a
H
b
N
c
O
d
S
e
that exhibit conformational polymorphism and have no fewer than four structurally characterized modifications are analyzed
using molecular Voronoi-Dirichlet polyhedrals. A unique combination of the types of occurring intra- and intermolecular nonvalent
contacts is shown to correspond to each conformational polymorph. Nonvalent interactions involving hydrogen atoms are found
to occur most often in crystal structures, and least often those involving S, N, and O atoms. 相似文献