基于g-C_(3)N_(4)/SH-CQDs复合材料的光电化学传感器检测Hg^(2+)  

Detection of Hg^(2+) by Photoelectrochemical Sensor Based on g-C_(3)N_(4)/SH-CQDs Composite Material

作　　者：胡禹 李瑞桢 杜立君 HU Yu;LI Ruizhen;DU Lijun(School of Chemical and Environmental Engineering,Sichuan University of Science&Engineering,Zigong 643000,China)

机构地区：[1]四川轻化工大学化学与环境工程学院,四川自贡643000

出　　处：《四川轻化工大学学报（自然科学版）》2023年第4期9-18,共10页Journal of Sichuan University of Science & Engineering(Natural Science Edition)

基　　金：国家自然科学基金项目(61601313);自贡市重点科技计划项目(2020YGJC04);四川轻化工大学人才引进项目(第二批)(2021RC09)。

摘　　要：汞离子在环境中易被微生物转化为毒性更大的甲基汞,会在食物链中进行富集,最终对人类产生毒害作用。因此,开发一种快速、经济、灵敏的方法准确检测环境中痕量的汞离子具有重要的意义。本研究采用简单的方法构建了基于石墨相氮化碳(g–C_(3)N_(4))/巯基碳量子点(SH-CQDs)复合材料的光电化学(PEC)传感器,其中g–C_(3)N_(4)作为光活性材料,SH-CQDs作为光敏剂,适量的SH-CQDs增强了复合材料的光电流响应,其光电流约为g–C_(3)N_(4)的1.8倍,这有利于提高PEC传感器的响应性能。另外,由于-SH(巯基)会与Hg^(2+)发生络合反应,使得复合材料能够将水中的Hg^(2+)成功吸附在电极表面产生位阻效应从而降低电极光电流信号强度。结果表明:制备的PEC传感器光电流信号强度变化与Hg^(2+)浓度在10~100 nmol/L的范围内有着良好的线性关系,线性相关系数为0.982,检出限为4.33 nmol/L(S/N=3)。值得注意的是,我国饮用水中允许的Hg^(2+)最高浓度约为5 nmol/L。这说明基于g–C_(3)N_(4)/SH-CQDs复合材料的PEC传感器成功实现了水中汞离子的灵敏检测。并且该传感器还展现了良好的稳定性和再现性。In the environment,mercury ions are easily converted into methyl mercury by microbes,which is more toxic,and easily accumulated in the food chain,and eventually produces toxic effects on human beings.Therefore,it is of great significance to develop a rapid,economical and sensitive method for accurately determining trace mercury ions in the environment.In the present study,a photoelectrochemical(PEC)sensor based on graphite-phase carbon nitride(g-C_(3)N_(4))/sulfhydryl functionalized carbon quantum dots(SH-CQDs)composite material has been fabricated by a simple method.Therein,g-C_(3)N_(4) is used as a photoactive material and SH-CQDs is used as a photosensitizer.And appropriate amount of SH-CQDs is introduced to enhance the photocurrent response of the composite material.It is observed that the photocurrent intensity of g-C_(3)N_(4)/SHCQDs is about 1.8 times than that of g-C_(3)N_(4),which is beneficial to improve the response performance of PEC sensor.In addition,due to the complexation reaction between sulfhydryl group(-SH)and Hg^(2+),the composite material can successfully capture Hg^(2+)from water onto the surface of the electrode,resulting in the decrease of electrode photocurrent signal intensity which can be attributed to the steric hindrance effect.The results show:the variation of photocurrent signal intensity of the prepared PEC sensor shows a good linear proportional relationship with the Hg^(2+)concentration in the range of 10~100 nmol/L.The linear correlation coefficient and the detection limit are estimated to be 0.982 and 4.33 nmol/L(S/N=3),respectively.It is noted that the maximum allowable Hg^(2+)level in drinking water in China is about 5 nmol/L.It is demonstrated that the developed PEC sensor based on g-C_(3)N_(4)/SH-CQDs is successfully applied to sensitively determine mercury ion in water samples.Moreover,the proposed sensor displayed high stability and good reproducibility.

关 键 词：光电化学传感器 氮化碳 巯基碳量子点 汞离子 

分 类 号：TP212.2[自动化与计算机技术—检测技术与自动化装置]