State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, PR China.
Water Res. 2013 Jul 1;47(11):3573-82. doi: 10.1016/j.watres.2013.04.004. Epub 2013 Apr 19.
A novel cathode, Pd loaded Ti/TiO2 nanotubes (Pd-Ti/TiO2NTs), is synthesized for the electrocatalytic reduction of trichloroethylene (TCE) in groundwater. Pd nanoparticles are successfully loaded on TiO2 nanotubes which grow on Ti plate via anodization. Using Pd-Ti/TiO2NTs as the cathode in an undivided electrolytic cell, TCE is efficiently and quantitatively transformed to ethane. Under conditions of 100 mA and pH 7, the removal efficiency of TCE (21 mg/L) is up to 91% within 120 min, following pseudo-first-order kinetics with the rate constant of 0.019 min(-1). Reduction rates increase from 0.007 to 0.019 min(-1) with increasing the current from 20 to 100 mA, slightly decrease in the presence of 10 mM chloride or bicarbonate, and decline with increasing the concentrations of sulfite or sulfide. O2 generated at the anode slightly influences TCE reduction. At low currents, TCE is mainly reduced by direct electron transfer on the Pd-Ti/TiO2NT cathode. However, the contribution of Pd-catalytic hydrodechlorination, an indirect reduction mechanism, becomes significant with increasing the current. Compared with other common cathodes, i.e., Ti-based mixed metal oxides, graphite and Pd/Ti, Pd-Ti/TiO2NTs cathode shows superior performance for TCE reduction.
一种新型阴极，负载钯的 Ti/TiO2 纳米管（Pd-Ti/TiO2NTs），被合成用于电催化还原地下水中的三氯乙烯（TCE）。钯纳米颗粒成功负载在 TiO2 纳米管上，TiO2 纳米管通过阳极氧化生长在 Ti 板上。在未分隔的电解槽中使用 Pd-Ti/TiO2NTs 作为阴极，TCE 被高效且定量地转化为乙烷。在 100 mA 和 pH 7 的条件下，TCE（21 mg/L）的去除效率在 120 分钟内达到 91%，遵循假一级动力学，速率常数为 0.019 min(-1)。当电流从 20 mA 增加到 100 mA 时，还原速率从 0.007 min(-1)增加到 0.019 min(-1)，在存在 10 mM 氯离子或碳酸氢根的情况下略有下降，并且随着亚硫酸盐或硫化物浓度的增加而下降。在阳极产生的 O2 对 TCE 的还原略有影响。在低电流下，TCE 主要通过 Pd-Ti/TiO2NT 阴极上的直接电子转移还原。然而，随着电流的增加，Pd 催化氢脱氯的间接还原机制的贡献变得显著。与其他常见的阴极相比，即 Ti 基混合金属氧化物、石墨和 Pd/Ti，Pd-Ti/TiO2NTs 阴极在 TCE 还原方面表现出优异的性能。
