首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
对甲苯磺酰胺和1.4—丁炔二醇在汞电极上的共吸附   总被引:1,自引:0,他引:1  
黄树坤  谢乃贤 《电化学》1995,1(3):313-318
用电毛细曲线、微分电容曲线、Stuart模型和自洽场分子轨道法(CNDO/2)研究对甲苯磺酰胺和1.4-丁炔二醇在汞电极上的共吸附特性。此共吸附本质上是一种物理吸附。在其最大的吸附电位附近,二者分别以侧卧方式吸附于表面,并在共吸附层表现出静电斥力作用作用。当两者的浓度相等时,1.4-丁炔二醇的吸附占优势。  相似文献   

2.
用表面增强拉曼散射光谱(SERS)和时间分辨SERS光谱(TRSERS)等技术首次研究了烯丙基硫脲(ATU)在HClO4、H2SO4和HNO3介质中与无机阴离子在银电极上的电化学共吸附行为.提出ATU很可能以S端与银电极表面形成化学吸附键,仲氨基相对伯氨基距离表面较近,整个分子偏向烯丙基一侧倾斜吸附在表面上.ClO-4、SO2-4和NO-3等弱吸附无机阴离子均能被ATU诱导共吸附在其质子化了的仲氨基上,这3种无机阴离子被ATU诱导共吸附的强弱顺序是ClO-4>SO2-4>NO-3.被诱导共吸附的无机阴离子对ATU在电极表面的化学吸附起到稳定剂的作用,有利于ATU在电极表面形成致密的吸附层  相似文献   

3.
鸟嘌呤—铜配合物在汞电极表面上的电吸附性的研究   总被引:1,自引:0,他引:1  
在0.02mol/L NaHCO3-0.05mol/La2SO4介质中、用极谱法和伏安法研究表明,铜-乌嘌呤配合物在汞电极表面上的吸附服从Langmuir吸附,测得其饱和吸附量Γm=1.1×10^-10mol/cm^2,吸附系数β=4.7×10^4,吸咐自由能△G°=-36.6kJ/mol。在8×10^-6mol/L Cu^2+离子存在下,可用示差脉冲阴极吸附溶出法测定8×10^-10~1×10^  相似文献   

4.
本文探讨了麻醉镇痛药物芬在尼的衍生物双-N-(1-苯甲基-4-哌啶基)-草酰对甲氧基苯基胺(DMPPE)在汞电极上的电化学行为。循环伏安法表明,在NaOH底液中,DMPPE可在汞电极上还原,Epc=-1.53V(vs.饱和Ag/AgCl),并可吸附于电极表面。着重考察了DMPPE的吸附特性,认为吸附型体是DMPPE中性分子。利用吸附伏安法进行微量DMPPE的测定,在最佳条件下,最低检测限可在4.0  相似文献   

5.
和厚朴酚的电化学行为及反应机理研究   总被引:3,自引:0,他引:3  
和顾朴酚在0.1mol/L NH3-NH4Cl缓冲溶液(PH9.4)中,用线必 安法得到两个还原峰P1和P2。峰电位分别为EP1=-0.23V和EP2=-1.18V(vs,Ag/AgCl)。用线性扫描与循环伏安法、脉冲极谱法和恒电位库仑法等手段研究体系的电化学行为及其反应机理。实验表明,P1和P2均为不可逆波。P1和P2的电子转移数均为2。和厚朴酚在汞电极上的吸附具有中性分子吸附的特征,吸附符合F  相似文献   

6.
钟起玲  刘峰名 《电化学》1997,3(2):185-190
用表面增强拉曼光谱技术研究了HClO4介质中硫脲,一甲基硫脲和烯丙基硫脲在银电极表面的共吸附行为。首次报道了它们的混合物在银电极表面上竞争共吸附随电极电位变化的行以及在所研究的共吸附体系中作为支持电解的弱吸附ClO^-4离子被诱导物理共吸附的现象。  相似文献   

7.
噻利洛尔的吸附伏安行为   总被引:1,自引:0,他引:1  
曾泳淮  李永明  陈小乐 《分析化学》1999,27(10):1136-1140
在NH3-NH4Cl底液中,噻利洛尔在汞电极上有一线性扫描还原峰,电位Epc=-1.31V(vs,Ag/AgCl),该峰具有明显的吸附性。当CEL浓度较小时,扫描较快,搅拌富集时间较长时,电极反应完全为吸附态的CEL的还原所控制,吸附粒子为CEL中性分子,测得CEL在汞电极上的饱和肿附量为1.03×10^-10mol/L,每个CEL分子所占电极面积为1.57nm^3,CEL在悬汞电极上的吸附符合L  相似文献   

8.
在0.1mol/LNH4Ac(pH7.8)底液中,氯氮平(CLP)在汞电极上有一线性扫描还原峰,Epc=-1.34V(vs.Ag/AgCl).该峰具有明显的吸附性,吸附粒子为CLP中性分子.测得CLP在汞电极上的饱和吸附量为2.7×10-10mol/cm2,每个CLP分子所占电极面积为0.62nm2,CLP在悬汞电极上的吸附符合Frumkin等温式.测得吸附系数β=6.28×105,吸引因素γ=0.75,电子转移数n为2,不可逆吸附的转移系数α为0.53.探讨了CLP在汞电极上的还原机理,并建立了吸附溶出伏安法测定CLP的最佳条件,检测限为8.0×10-9mol/L.  相似文献   

9.
王曙  肖腾文 《分析化学》1995,23(8):899-902
在pH=5.0的HAcNaAc介质中,Nb(Ⅴ)与1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5(PMBP)生成络合物,于一0.96V(vs.SCE)出现一尖极谱波。在滴汞电极上用示波极谱仪或在悬汞电极上则吸附伏安曲线。峰电流与Nb(Ⅴ)浓度分别在0.0075-0.80μg/mL及0.000075-0.0075μg/mL范围内呈线性关系。实验 3  相似文献   

10.
循环伏安法表明,在NaOH底液中核黄素丁酸酯(riboflavine tetrabutyrate,RT)在汞电极上有一对氧化还原峰,其峰电位Epc=Epa=-0.64V(vs.Ag/AgCl)。本文用多种电化学手段对RT的吸附特性进行了较详细的研究。吸附粒子为RT中性分子,测得RT在汞电极上的饱和吸附量为5.42×10-11mol/cm2,每个RT分子所占电极面积为3.06nm2,RT在悬汞电极上的吸附符合Frumkin等温式。测得吸附系数β=4.6×105,吸引因素γ= 1. 10,吸附自由能△G°=- 32. 30 kJ/mol。本文还用循环伏安法研究了RT的电极反应动力学性质,测定了其在汞电极上的反应速率常数。  相似文献   

11.
For the first time, the new microwave-assisted method for the synthesis of copper phyllosilicates on a commercial SiO2 carrier was developed. The application of microwave synthesis allowed to decrease the synthesis time from 9 to 6 h compared to the traditional DPU method of preparing chrysocolla. The synthesized catalysts were studied by N2 adsorption, TEM and XRD methods. Catalysts prepared by microwave method are highly effective in the selective hydrogenation of the С≡С bond in 1,4-butynediol to 1,4-butenediol and 2-phenylethinylaniline with a selectivity of 96.5% and 100% at full conversion for 2 and 0.5 h of the reaction, respectively.  相似文献   

12.
Metallopropargylation of a number of carbazoles was performed by dicobalt hexacarbonyl complexes with propargyl alcohol and 1,4-butynediol in the presence of boron trifluoride etherate. It was shown that depending on the substituents position in the carbazole ring occurred either N- of C-propargylation; with 1,4-butynediol formed also oligomeric products.  相似文献   

13.
The electrodeposition kinetics of a tin-indium alloy from a sulfate electrolyte in the simultaneous presence of synthanol DS-10, formalin, and 1,4-butynediol was studied by a Faraday impedance method.  相似文献   

14.
利用ALD制备了TiO2限域的Pd催化剂, 研究了限域空间内Pd纳米颗粒与TiO2的界面作用对1,4-丁炔二醇(BYD)加氢性能的影响. 相比于管外负载型催化剂, 限域催化剂在催化1,4-丁炔二醇选择性加氢反应中体现出非常高的催化活性和1,4-丁烯二醇的选择性. HR-TEM、 EDX-Mapping、 XRD、 XPS和H2-TPR表征说明, 限域体系中Pd-TiO2的界面相互作用强于传统TiO2表面负载型Pd催化剂, 这种强界面作用不仅能够提高BYD的加氢活性, 也可抑制半加氢产物1,4-丁烯二醇的异构化和深度加氢, 提高1,4-丁烯二醇的选择性, 而且限域结构也可阻止管内壁Pd纳米颗粒的脱落, 提高催化剂的稳定性.  相似文献   

15.
We present a synergistic experimental and theoretical study of CO(2)/CH(4) mixture coadsorption in breathing metal-organic framework MIL-53(Al). Mixture adsorption experiments were performed and their results were analyzed by comparing them to predictions made from pure-component adsorption data using the Osmotic Framework Adsorption Solution Theory (OFAST). This analytical model, fully validated for the first time, was then used to predict coadsorption properties as a function of temperature, pressure, and mixture composition. The phase diagrams obtained show a surprising non-monotonic behavior.  相似文献   

16.
The effect of organic surfactants (1,4-butynediol, benzoic and disulfonaphthalene acids) on electrochemical properties of heterogeneous ion-exchange membranes MK-40 and MA-40 is studied. The surfactants effect the membrane properties both under equilibrium conditions and, especially, in the electric field, suggesting that they are involved in both the exchange sorption and the electrotransport. The mechanism of their effect on the anionite membrane is considered. It is shown that bipolar boundaries can arise in the membrane, promoting water dissociation and transport of hydrogen and hydroxyl ions in the field direction.  相似文献   

17.
We performed a theoretical study of the adsorption of oxygen on a cluster model of the Cu(100) surface and also the surface coadsorbed with lithium and potassium atoms. The study showed that alkali coadsorption facilitates in a significant way the process of molecular adsorption, whereas the adsorption of atomic oxygen is only slightly modified. The alkali atoms on the copper surface produce an increase in the charge transfer toward the oxygen molecule, favoring the oxygen dissociation. The effect is greater for the potassium coadsorption. In addition, we found that the potassium coadsorption favored the dissociation and recombination processes by about 60 and 15%, respectively. In turn, the lithium coadsorption favored only the recombination process by about 50%. These results could be an important aspect for catalytic processes.From the Proceedings of the 28th Congreso de Quimicos Teóricos de Expression Latina (QUITEL 2002)  相似文献   

18.
应用电化学循环伏安方法(CV)和原位傅里叶变换红外反射光谱(in situ FTIRS)研究了酸性溶液中Pt多晶电极表面NO和CO的共吸附行为及吸附态CO对吸附物种NO氧化还原反应的影响.研究结果表明,0.20V(VS.SCE)时,CO和NO能同时稳定吸附在Pt电极表面,CO以线性吸附态(CO L)存在,NO以桥式吸附态(NOB)和线性吸附态(NO L)共存.CO L 的共存使得NO的还原电流峰电位负移约0.024V,并且促使不易被氧化的NO B在0.93V处被氧化.原位FTIRS研究进一步表明,NO可以置换预吸附在电极表面的CO,NO和CO在Pt多晶电极表面的吸附是一个竞争吸附的过程.在0.45V-1.2V电位区间,NO和CO都能转化为环境友好产物,分别为NO3-和CO2.且Pt电极表面共吸附物种CO的量直接影响NO B的氧化产物NO3-的生成量.  相似文献   

19.
We present the results of a density functional calculation on adsorption of O2, CO, and their coadsorption at various sites of neutral, cationic, and anionic Pd4 clusters. For all the clusters, the dissociative adsorption of oxygen sitting on Pd bridge sites is found to be preferable. Both O2 and CO binding energies are found to be higher for the anionic Pd4 cluster followed by cationic and neutral cluster. However, binding energies of O2 or CO in the coadsorption complexes follow the trend: anionic > neutral > cationic. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010  相似文献   

20.
Possible coadsorption states of Ti mononuclear species and ethyl benzoate (EB) and their interaction on MgCl2 (110) and (100) surfaces were investigated with periodic density functional calculations in order to obtain the microscopic understanding about how EB affects the steric and electronic natures of the Ti species. EB was unlikely to be attached to the TiCl4 species on both the MgCl2 (110) and (100) surfaces. The coadsorption of EB at Mg2+ ions near the Ti species was as favorable as the separate adsorption, which implied the random placement of these adsorbants in the final catalyst. The charge redistributions upon coadsorption among the Ti species, EB and the support were found to be dependent on the surface structures: the electron density of the Ti speceies was rather decreased by the coadsorption on the (100) surface, while that of the Ti species was enhanced due to the support-mediated electron transfer from EB on the (110) surface. It was suggested that the presence of EB close to the Ti species should generate donor-related active sites selectively on the (110) surface.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号