Photocatalytic oxidation of cyanide on TiO2:: An electrochemical approach
Photocatalytic oxidation of cyanide on TiO2:: An electrochemical approach
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DOI：
10.1016/j.cattod.2007.12.063
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发表时间：
2008-04-01
期刊：
影响因子：
5.3
通讯作者：
Pedraza-Rosas, J. E.
中科院分区：
文献类型：
--
作者：
Pedraza-Avella, J. A.;Acevedo-Pena, P.;Pedraza-Rosas, J. E.
采用伏安法、线性极化电阻法和塔菲尔极化法研究了TiO 2-碳糊电极（TiO 2-CPE）光催化氧化氰化物的性能。在所有情况下，观察到UV-vis照明对氧化电流（即氧化速率）的积极影响，显示了这种类型的电极用于粉末状半导体光催化剂的电化学评价的便利性。伏安法的结果表明，氰化物（CN-）的氧化发生在较低的电位比氢氧根离子（OH-）的氧化;氰化物被氧化为氰酸根（CNO-），并在高电位下，它可以进一步氧化与OH-一起。线性极化电阻曲线表明，该过程受电子转移控制。从阳极和阴极极化曲线的塔菲尔斜率，使反应的内在动力学参数的测定（即速率常数，反应级数）。紫外-可见光照射导致反应速率的增加，与速率常数的增量有关，CN-和OH-离子的反应级数减少。(C)2008 Elsevier B. V.保留所有权利。
Photocatalytic oxidation of cyanide on TiO2 was studied by means of voltammetry, linear polarization resistance and Tafel polarization using TiO2-carbon paste electrodes (TiO2-CPEs). In all cases, a positive effect with UV-vis illumination on the oxidation current (i.e. oxidation rate) was observed, showing the convenience of this type of electrodes for the electrochemical evaluation of powdered semiconductor photocatalysts. Voltammetric results indicated that the oxidation of cyanide (CN-) occurs at lower potentials than the oxidation of hydroxyl ions (OH-); cyanide is oxidized to cyanate (CNO-) and at high potentials it can further be oxidized together with OH-. Linear polarization resistance curves showed that the process is controlled by electron transfer. Tafel slopes from the anodic and cathodic polarization curves enabled the determination of the intrinsic kinetic parameters of the reaction (i.e. rate constant, reaction orders). UV-vis illumination led to an increase in the reaction rate, related to the increment in the rate constant, and a decrease in the reaction orders for both CN- and OH- ions. (C) 2008 Elsevier B.V. All rights reserved.