共查询到20条相似文献,搜索用时 250 毫秒
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纳米超微电极的研究(Ⅳ)──超微金柱电极的制作与表征张学记,万其进,张悟铭,周性尧(武汉大学化学系,武汉,430072)关键词微电极,纳米超微电极,伏安法,离子束,金纤维最近,纳米超微电极[1~5]的研制成功,使超微电极的研究进入一个新阶段,给电化学... 相似文献
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纳米级超微电极的研究(Ⅰ)—超微带电极的研制,表征及应用 总被引:3,自引:1,他引:3
报道了纳米级超微带电极的制作方法,并分别用扫描隧道电镜、扫描电镜和光电子能谱对电极表面进行表征、用循环伏安法、计时电流法考察了电极的性能、将半微柱的扩散模型用于描述50nm以上的超微带电极,结果表明,超微带电极的带宽对电流变化影响不大,而非法拉第电流却正比于电极面积.用超微带电极可提高信噪比,测定亚铁氰化钾检测限可达5.0×10~(-7)mol/L. 相似文献
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稳态循环伏安法具有简单、快速判别电极性能和估算电极尺寸的特性,因而被广泛应用于超微电极的表征.但纳米电极由于尺寸极小,其表面形貌的细微变化对电化学行为有明显的扰动,从而影响纳米电极表征的准确性.结合电化学实验和有限元模拟,探讨了纳米电极尺寸、绝缘层半径和电极半径之和与电极半径之比(RG)和尖端孔道对稳态电流的影响.研究表明尺寸较小(r ≤ 80 nm)的纳米圆盘电极,由于反应速率相对扩散较慢,电极反应过程受动力学效应控制,使稳态电流曲线偏离半球形扩散控制的标准"S"型.此外RG值较小的纳米圆盘电极,物质到电极的传递被增强,使极限电流值增大.我们对内嵌式纳米电极进行了进一步研究,并发现电极尖端孔道阻碍了电活性物质的扩散,削弱了动力学的限制,使极限电流值低于同尺度的纳米圆盘电极,伏安电流曲线呈现标准的"S"型.本研究系统地探讨了电极尖端形貌与稳态电流的相互关系,加深了对纳米电极电化学行为的理解. 相似文献
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《Electroanalysis》2006,18(15):1493-1498
Titanium nitride was used as pH‐sensitive material to fabricate all solid‐state pH electrode. The fabrication and the response performance of the pH electrode were described in the paper. The TiN film electrode showed a linear response in the pH range of 2–12 with a near‐Nenstian response (?55 mV/pH). The response time was within 1 min, and the electrode had good reproducibility, stability and low sensitivities for different species. Compared with the glass pH electrode, the electrode exhibited some advantages, for example, without activation, rapid response and high mechanical strength. In addition, the electrode performed excellently in a corrosion medium containing F?(1 M). Electrochemical behaviors of TiN electrode in Britton‐Robinson buffers were studied with Electrochemical Impedance Spectroscopy (EIS). 相似文献
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p H值是溶液化学中重要的检测指标 .在工业、农业、生物、医学及环境保护等各个领域都有着广泛应用 .目前 ,多采用玻璃 p H电极进行 p H值的测量 .然而 ,玻璃 p H电极也存在一定的不足 ,玻璃敏感膜阻抗高达 1 0 10 Ω,容易造成电磁干扰 ;玻璃 p H电极极易破碎 ,难以适用于强搅拌的工业过程体系 ;氢氟酸能强烈地浸蚀玻璃膜 .因此 ,玻璃 p H电极不能长时间地用于含氟腐蚀体系 p H的测量 ;另外 ,玻璃 p H电极在强碱性溶液测量时会产生“钠差”.因此 ,多年来对非玻璃型 p H电极的研究一直是化学传感器研究领域中的活跃课题之一 .目前常见的… 相似文献
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纳米Co3O4型固体pH电极的响应及应用 总被引:2,自引:0,他引:2
测定酸度目前广泛采用玻璃电极 .然而 ,由于玻璃电极是采用极薄的玻璃膜作为 H+的敏感膜 ,致使电极极易破碎 ,亦难以用于对玻璃有腐蚀作用的体系 ,如含氟体系 .此外它还具有体积大、成本较高、膜阻抗高而难以实现微型化、以及使用前需活化处理等缺点 .多年来对非玻璃型 p H电极的研究一直是个热门的研究课题 .其中以金属 /金属氧化物型固体 p H电极倍受关注 [1~ 6 ] .本文对氧化钴 (Co3 O4 )型固体 p H印刷电极的响应性能、选择性、重现性以及在含氟腐蚀体系 p H测定中的应用进行了研究 .Ф1 2型 p H计 (BECKMAN公司 ) ,2 3 2型饱和… 相似文献
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Teixeira MF Ramos LA Almeida Neves E Fatibello-Filho O 《Fresenius' Journal of Analytical Chemistry》2000,367(1):86-89
The construction and the application of a silica gel based carbon-epoxy indicator electrode for the potentiometric determination of acids and bases are described. The effect of composition of silica gel and carbon-epoxy, slope (mV/pH), linear response (pH range) and the use for acid-base titrations were investigated. The data obtained for the acid-base titrations were compared with those obtained using a glass electrode in the same conditions. The electrode showed a linear response in the pH 2 to 13 range with a slope of -40.5 +/- 0.4 mV/pH (at 25 degrees C) and a response time of less than 15 s. The lifetime of the electrode was higher than one year (over 6000 determinations) with a decrease of only 5% of the initial potentiometric response. The silica gel based carbon-epoxy electrode showed excellent results in the end-point indication potentiometric titrations in determination of acids and bases. The miniaturization of the proposed electrode for flow injection analysis was investigated. 相似文献
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Demet Kuruo?lu Esin Canel Shahabuddin Memon Mustafa Yilmaz Esma Kili? 《Analytical sciences》2003,19(2):217-221
A hydrogen ion-selective poly(vinyl chloride) membrane electrode was constructed using 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetracyanomethoxycalix[4]arene as a neutral carrier. The electrode showed an apparent Nernstian response in the 2-11.5 pH range with a slope of 54.0 +/- 0.2 mV/pH at 20 +/- degrees C. This electrode showed a rapid response of the emf to changes in the pH, high ion selectivity with respect to lithium, sodium and potassium, and characteristics similar to those reported for the conventional pH glass membrane electrode. It can be used as a potentiometric indicator electrode in hydrofluoric acid solutions. The effects of iodide, thiocyanate, perchlorate and bromide on the characteristics of the electrode were also considered. 相似文献
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M. F. S. Teixeira L. A. Ramos E. Almeida Neves O. Fatibello-Filho 《Analytical and bioanalytical chemistry》2000,367(1):86-89
The construction and the application of a silica gel based carbon-epoxy indicator electrode for the potentiometric determination
of acids and bases are described. The effect of composition of silica gel and carbon-epoxy, slope (mV/pH), linear response
(pH range) and the use for acid-base titrations were investigated. The data obtained for the acid-base titrations were compared
with those obtained using a glass electrode in the same conditions. The electrode showed a linear response in the pH 2 to
13 range with a slope of –40.5 ± 0.4 mV/pH (at 25 °C) and a response time of less than 15 s. The lifetime of the electrode
was higher than one year (over 6000 determinations) with a decrease of only 5% of the initial potentiometric response. The
silica gel based carbon-epoxy electrode showed excellent results in the end-point indication potentiometric titrations in
determination of acids and bases. The miniaturization of the proposed electrode for flow injection analysis was investigated.
Received: 11 August 1999 / Revised: 4 October 1999 / Accepted: 7 October 1999 相似文献
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本文研究了在玻碳电极上修饰不同物质所制得的pH传感器,通过电位滴定的方法比较得出先修饰聚苯胺,再修饰钴-氧化钴膜的电极对pH有较好的响应,能代替玻璃电极应用在实际样品测定中。探究了最佳修饰条件为:先在0.1mol/L苯胺的盐酸(1mol/L)溶液中, 电位范围为-0.2~1.0V,以100 mV/s 的扫描速度循环伏安扫描 10圈修饰聚苯胺膜;接着在含2.0×10-4 mol/LCo2+的PBS (pH=7.5)缓冲溶液中, 电位范围为-1.2~1.2V,以100 mV/s 的扫描速度循环伏安扫描 5圈修饰钴-氧化钴膜。得到的修饰电极响应斜率为-61.60 mV/pH,响应范围pH 0.5~13。 相似文献
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A chemically modified electrode (CME) for use as a potentiometric pH sensor was constructed by electropolymerizing a poly(4,4′-diaminobiphenyl) coating on a platinum electrode. The resulting CME gave a linear response to pH in the range 1–12 with a slope of ?56 mV pH?1. The CME functioned well in titration experiments and in pH measurements. No significant interference of a coexisting redox couple with the pH measurements was observed. The mechanism of the pH response of the CME is considered. 相似文献