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1.
采用浸渍法制备了一系列γ-Al2O3负载的Cr-Ag双金属氧化物催化剂,并考察了对CO的氧化活性.结果表明,由Cr(NO3)3、CrO3、Cr2(C2O4)3作为Cr源制备的单组分Cr-/γ-Al2O3催化剂对CO的氧化活性基本相同,且均较差;但添加少量Ag(<2wt%)却能明显提高Cr/γ-Al2O3催化剂对CO的氧化活性,且分步浸渍法制备的Cr-Ag/γ-Al2O3双组分催化剂的活性明显优于用其浸渍法制备的催化剂 相似文献
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氧化镧对Cu—O/γ—Al2O3催化剂活性和结构的影响 总被引:1,自引:0,他引:1
在色谱-微反流动法实验装置上考察了三种催化剂对CO和CH4的氧化活性,并运用BET、XRD及TPR等技术研究了La2O3的添加对Cu-O/γ-Al2O3催化剂性能及催化剂氧化还原特性的影响.结果表明,La2O3的添加不仅使La2O3与CuO之间产生相互作用,且也与载体γ-Al2O3产生相互作用;La2O3的添加促进了CuO在γ-Al2O3上的分散,并使CuO均以非晶相形式存在,从而改善了Cu-O/γ-Al2O3催化剂对CO和CH4的氧化活性,还使La-Cu-O/γ-Al2O3催化剂的TPR峰温降低了75℃. 相似文献
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氧化物催化剂表面过剩氧与氧化活性 总被引:1,自引:0,他引:1
本文采用肼法测定了金属氧化物催化剂表面过剩氧的浓度,并考察了吡啶的氧化活性。催化剂的氧化活性与表面氧浓度成正比。氧化活性和表面氧浓度的顺序为:Cu-O/Al_2O_3>Mn-O/Al_2O_3>Cr-O/Al_2O_3>Fe-O/Al_2O_3≥Co-O/Al_2O_3>Ni-O/Al_2O_3>Ce-O/Al_2O_3.随着催化剂焙烧温度的提高,催化剂表面氧浓度和氧化活性均下降。Cu-O/SiO_2催化剂中添加CeO_2后,催化剂表面氧浓度和氧化活性均有明显提高,同时催化剂的热稳定性也明显增加。 相似文献
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本文使用相转移催化剂(TBAB)合成了空间位阻大、碳链长的6个含特丁基的三羟甲基烷烃t-Bu(CH2)nC(CH2OH)3(n=0、1、2、3、4、6),测定了这些化合物的熔点,进行了元素分析、质谱、红外光谱鉴定。 相似文献
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马维志 《内蒙古科技与经济》1998,(4)
1原理①2〔Ag(S2O3)2〕3-+S2-Ag2S↓+4S2O2-3②3Ag2S+2AlΔ6Ag+Al2S3+热量注:②反应放出的热量极大,类似铝热反应,可使银在反应中熔为液态而聚集于钳锅底部结为银块。2步骤2.1从医院或照相部购买废定影液后,加入... 相似文献
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用化学还原法制备了非晶态合金催化剂Ni-B、Co-B和Co-Ni-B.合金的非晶性质由X射线衍射(XRD)及透射电子显微镜(TEM)鉴定.组成用电感耦合等离子发射光谱(ICP)分析.在高真空程序升温脱附质谱(TPD-MS)装置上研究了CO、H2在三种催化剂上的吸附及CO和H2的表面反应(TPSR).发现CO和H2在三种催化剂上分别有二种和一种吸附态,吸附强度和二种吸附态的数目在不同合金上有较大差异.CO加氢反应的主要产物是CH4、CO2和H2O,其中CO在催化剂表面上的解离是反应的控制步骤. 相似文献
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负载Cu,Ag氧化物催化剂的氧化活性和热稳定性 总被引:1,自引:0,他引:1
考究了Al2O3,CeO2,TiO2负载Cu,Ag氧化物催化剂的氧化活性及CuO/CeO2,CuO/Al2O3催化剂的稳定性。结果表明,载体对催化剂的活性有明显影响,对于CO氧化,Cu系催化剂中CuO/CeO2活性最高,Ag系催化剂中,Ag2O/Al2O3活性最好。 相似文献
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采用梯度淋洗离子色谱法对碱金属、碱土金属及其铵类进行分析,该方法采用CG3分离柱,0.3mmol/LHCl为淋洗剂,4min后改用3.0mmol/L盐酸间苯二胺和5.0mmo1/LHCl作淋洗剂(流速2.0ml/min)采用微膜抑制柱,再生液为50mmol/LKOH(流速2.0ml/min),用电导检测法分别检测Li ̄+、Na ̄+、NH、K ̄+和Mg ̄(2+)、Ca ̄(2+)、Sr ̄(2+)、Ba ̄(2+).对分析条件进行了探讨. 相似文献
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CRYSTALSTRUCTURESOFCHARGETRANSFERSALTS(TTMTTF)_2Cu_2Cl_6ANDC_(40)H_(72)N_6Se_4NiChenXue-an;YangXue-yong;WuPei-ji;ZhuDao-ben;FuHe?.. 相似文献
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茶多酚抗突变和消除自由基作用的研究 总被引:6,自引:0,他引:6
采用E.ColiSOS显色法,小鼠骨髓细胞微核及染色体畸变试验和体外自由基消除实验等方法测定了茶多酚复合物(TP)的抗突变和消除自由基作用.结果表明:(1)TP的终浓度在2.5和5mg/ml时,对由阳性致突变物MNNG,EMS和NaN_3诱导的SOS应答反应均具有明显的抑制作用;(2)小鼠每日ig40、80和120mg/kg剂量的TP能明显抑制由环磷酰胺(CP)诱发的骨髓PCE的MNCF,三种剂量TP的抑制率分别为40.98%、66.76%和65.94%;(3)TP对MMC诱发的骨髓细胞染色体畸变(CA)的抑制率分别为62.56%、55.71%和47.95%;(4)在X/XO-ESR、X/XO/Luminol-BCL和IR/NBT-SPM三种模型中TP对超氧阴离子O_2自由基均具有极强的消除作用,消除率分别为98±6%、98±1.2%和95±1.5%,对O_2的消除效率明显强于维生素C和E,对不同工艺制备的TP消除活性氧自由基作用的测定结果显示:脱咖啡碱程度高,EGC和L-EGCG含量比例高的TP-3制剂消除O_2的效率最高.因此,TP消除有害自由基,中断或终止自由基的氧化反应是抗突变,抗肿瘤作用的主要机制 相似文献
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《Electronic Journal of Biotechnology》2014,17(3):122-125
BackgroundA biosurfactant produced by Pseudomonas aeruginosa cultivated in a low-cost medium formulated with 2.5% vegetable oil refinery residue and 2.5% corn steep liquor and distilled water was employed to stabilize silver nanoparticles in the liquid phase. The particles were initially synthesized using NaBH4 as reducing agent in biosurfactant reverse micelles and were extracted from the micellar solution to disperse in heptane.ResultsA silver particle size in the range of 1.13 nm was observed. The UV–vis absorption spectra proposed that silver nanoparticles could be formed in the reverse micelles and relatively stabilized for at least 3 months without passivator addition. The Transmission Electron Microscope (TEM) shows that the silver nanoparticles are of spherical form and relatively uniform.ConclusionsThis process provided a simpler route for nanoparticle synthesis compared to existing systems using whole organisms or partially purified biological extracts, showing that the low-cost biosurfactant can be used for nanoparticle synthesis as a non-toxic and biodegradable stabilizing agent. 相似文献
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卤化银-明胶全息的研究进展 总被引:1,自引:0,他引:1
对卤化银-明胶的全息性质进行了全面综述.对不同类型全息图的形成机理和影响其衍射效率的各种因素进行了详细讨论,并展望了这种全息材料的发展前景 相似文献
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Gold nanoparticles (Au NPs) were directly synthesized on the surface of polyvinylsilazane (PVSZ, -[(vinyl)SiH-NH2]-) without use of extra reductive additives. The reductive Si-H functional groups on the surface of cured PVSZ acted as surface bound reducing agents to form gold metal when contacted with an aqueous Au precursor (HAuCl4) solution, leading to formation of Au NPs adhered to silicate glass surface. The Au NPs-silicate platforms were preliminarily tested to detect Rhodamine B (1 μM) by surface enhanced Raman scattering. Furthermore, gold microelectrode obtained by post-chemical plating was used as an integrated amperometric detection element in the polydimethylsilane-glass hybrid microfluidic chip. 相似文献
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Frederick G. Germuth 《Journal of The Franklin Institute》1930,210(3):345-351
It has been shown that 0.15 N hydrogen chloride solution is most suitable for employment as precipitant in the quantitative estimation of silver ion, this procedure reducing adsorption to a minimum.When a more dilute solution of reagent is applied, there is a tendency for a portion of the silver to remain dissolved.When hydrogen chloride possessing a greater concentration than 0.15 N is utilized in this determination, adsorption of Cl? ion, and, to a lesser extent, of Ag+ ion, readily occurs.The data presented here have been obtained by careful application of a recognized method, during the course of which temperature effect, and solubility data were given due consideration. Meticulous nephelometric examination was subsequently accorded each experimental sample prior to the calculation of results. 相似文献
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(1) A method of preparing photohalide emulsions somewhat different from that of Lüppo-Cramer has been worked out, using either colloidal silver or colloidal silver sulphide as the sensitizer.(2) Treatment of the plates containing this emulsion with chromic acid to remove excess colloidal silver also lowers sensitivity considerably. This sensitivity can be restored by an after-treatment of the plates with a very dilute ammonia solution.(3) The photohalide emulsion prepared as described showed, with one exception, a broader spectral sensitivity than those prepared without colloidal silver or silver sulphide. This agrees with the previous work of others on photohalide emulsions.(4) The spectral sensitivity of such emulsions differs from those sensitized with allyl-thiourea sensitizer in being more sensitive in the red and less sensitive in the green region of the spectrum.(5) The present work supports the strain-ionic deformation hypothesis of sensitivity proposed by Sheppard, Trivelli and Loveland. It does not, however, exclude the hypothesis of Hickman as to the role played by the silver sulphide sensitizing speck. 相似文献
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