中文摘要：

利用简单方法合成了水溶性的巯基乙酸修饰的硫化镉（CdS）量子点.通过静电吸附,用聚二甲基二烯丙基氯化铵（PDDA）将CdS修饰到氧化铟锡（ITO）电极上.在电子供体三乙醇胺（TEA）的存在下,CdS修饰的ITO电极具有稳定的阳极光电流.Hg2＋原位吸附于CdS表面形成的p型半导体HgS与n型半导体CdS形成p-n结,能够促进电子-空穴的分离与电荷传输,使CdS量子点的光电流增大.研究了反应前驱体中Cd,S摩尔比、反应溶液的pH值、回流时间等条件对所合成的量子点与Hg2＋相互作用的影响.此外,还研究了电解质溶液的pH值、外加电压、反应时间对Hg2＋增大CdS量子点光电流的影响.基于此,构建了灵敏检测Hg2＋的光电化学传感器.该传感器对Hg2＋响应的线性范围为4.0×10-8～2.0 ×10-5 mol/L,检出限为2.4×10-8mol/L,回收率为98.3％～103.5％.

英文摘要：

Water-soluble thioglycollic acid capped CdS quantum dots （QDs） were prepared using a simple method.CdS QDs were assembled on the surface of tin indium oxide （ITO） electrode through the electrostatic interaction between negatively charged thioglycollic acid on the surface of CdS and positively charged poly dimethyl diallyl ammonium （PDDA）.The CdS QDs modified ITO electrode showed a stable anodic photocurrent in the presence of triethanolamine（TEA） as an electron donor（or hole scavenger）.When the CdS QDs modified ITO electrode was immersed in Hg2＋ solution,an obviously enhanced photocurrent of CdS QDs was observed.The in-situ formation of HgS,a p-type semiconductor,on the surface of n-type CdS semiconductor led to the formation of a p-n junction,which facilitated the charge carrier transport and promoted electron-hole separation,triggered an obviously enhanced anodic photocurrent of CdS QDs.Effects of synthetic conditions such as molar ratio of Cd/S,pH value of reaction solution and reflux time on photoelectrochemical response of CdS QDs to Hg2 ＋ were investigated.Effects of pH value of the supporting electrolyte,applied potential and reaction time between CdS and Hg2＋ on photocurrent enhancement（I/I0） of CdS QDs by Hg2＋ were also investigated.Based on this,a sensitive Hg2 ＋ photoelectrochemical sensor was developed.The sensor showed a linear response to Hg2＋ in the concentration range of 4.0 × 10-8-2.0 × 10-5 mol/L,with a detection limit of 2.4 × 10-8 mol/L.The method was applied in the detection of Hg2＋ in lake water samples with recoveries of 98.3％-103.5％.