基于纳米复合材料的光电化学和电化学传感器的构建及应用
发布时间：2018-08-14 15:15
【摘要】：本文制备了CdS量子点、TiO2等纳米材料,并分别与石墨烯或氯化血红素复合,构建具有高催化性能的新型光电/电化学传感器。使用FESEM、XRD、UV-Vis、电化学检测等方法对纳米复合材料的表面形貌、结构、光学和电化学性质进行了表征。将新型光电/电化学传感器应用于环境污染物和H2O2的灵敏检测,研究了对苯二胺的光伏行为以及催化机理。主要内容包括以下两个方面:1、本部分采用水热法合成了水溶性CdS量子点,掺杂适量石墨烯(GS)后制备了CdS-GS/FTO膜修饰电极。石墨烯的掺杂使CdS量子点薄膜的光电化学性能得到大幅提高。在可见光照射下,由于光电催化反应的存在,对苯二胺(PPD)在CdS-GS/FTO上的循环伏安图呈现“S”形,这一响应被用于膜材料比例的快速优化。扫描速率和pH对PPD光伏行为的影响表明,在光辐照下尽管电化学过程的控制步骤没有发生改变,却有相比质子数目更多的电子可能参与到光电催化过程中。此外,光电活性的膜修饰电极被应用于对苯二胺的灵敏检测。这种光电化学传感器在最优条件下对PPD的线性响应范围为1.0?10-7~3.0?10-6 mol·L-1,检出限(3S/N)为4.3?10-8 mol·L-1。本部分通过光伏方法研究了PPD在电极上的光诱导电子转移过程,并提出了一种PPD灵敏检测的光电化学方法。2、采用火焰气溶胶合成技术制备的TiO2纳米颗粒,与氯化血红素(Hemin)复合,制备了具有电催化活性和光电活性的双功能Hemin-TiO2/GCE电极。循环伏安表征显示Hemin-TiO2复合膜上清晰地显现出Hemin的一对氧化还原峰,探讨了扫描速率、电解液pH对修饰电极电化学行为的影响。Hemin-TiO2/GCE修饰电极对H2O2有良好的电催化还原活性,在3.0?10-7 mol·L-1至4.7?10-4 mol·L-1范围内对H2O2具有良好的线性关系,检出限(3S/N)为7.2?10-8 mol·L-1。同时,Hemin-TiO2复合膜还保留了TiO2的光电化学活性,Hemin的掺杂能够帮助TiO2吸收一部分的可见光,阻碍了TiO2光生电子空穴对(e-/h+)的复合,从而进一步提高了电极对可见光的光电响应。基于此构建了一种用于对苯二酚定量检测的光电化学传感器,线性响应范围是4.0?10-7 mol·L-1到3.0?10-5 mol·L-1,检出限(3S/N)为9.8?10-8 mol·L-1。该传感器已成功地用于对苯二酚降解率的测定。
[Abstract]:In this paper, CdS quantum dots TiO2 and other nanomaterials were prepared and combined with graphene or hemin, respectively. A novel photoelectric / electrochemical sensor with high catalytic performance was constructed. The surface morphology, structure, optical and electrochemical properties of the nanocomposites were characterized by Fesemer XRDX UV-Visand electrochemical detection. A novel photoelectric / electrochemical sensor was applied to the sensitive detection of environmental pollutants and H2O2. The photovoltaic behavior and catalytic mechanism of p-phenylenediamine were studied. The main contents include the following two aspects: 1. In this part, water-soluble CdS quantum dots were synthesized by hydrothermal method. CdS-GS/FTO film modified electrode was prepared by doping proper amount of graphene (GS). The photochemical properties of CdS quantum dot films are greatly improved by the doping of graphene. Under visible light irradiation, the cyclic voltammogram of p-phenylenediamine (PPD) on CdS-GS/FTO presents a "S" shape due to the existence of photocatalytic reaction, which is used to optimize the ratio of membrane materials. The effects of scanning rate and pH on the photovoltaic behavior of PPD show that, although the control steps of the electrochemical process have not changed under light irradiation, more electrons than the number of protons may be involved in the photocatalytic process. In addition, photoactive membrane modified electrodes are used for sensitive detection of p-phenylenediamine. Under the optimum conditions, the linear response range of the photochemical sensor to PPD is 1.0 脳 10 ~ (-7) ~ 3.0 ~ (-1) mol ~ (-6) mol L ~ (-1) and the detection limit (3S/N) is 4.3 ~ (-8) mol / L ~ (-1). In this part, photoinduced electron transfer of PPD on the electrode was studied by photovoltaic method, and a photochemical method of PPD sensitive detection was proposed. The TiO2 nanoparticles were prepared by flame aerosol synthesis technology and combined with hemin (Hemin). Two functional Hemin-TiO2/GCE electrodes with electrocatalytic activity and photovoltaic activity were prepared. Cyclic voltammetry analysis showed that a pair of redox peaks of Hemin appeared clearly on Hemin-TiO2 composite film. The effects of scanning rate and pH of electrolyte on electrochemical behavior of modified electrode. Hemin-TiO2 / GCE-modified electrode had good electrocatalytic reduction activity to H2O2. There was a good linear relationship for H2O2 in the range of 3.0 ~ 10 ~ (-7) mol ~ (-1) to 4.7 ~ (-4) mol L ~ (-1). The detection limit (3S/N) was 7.2 ~ (-8) mol L ~ (-1). At the same time, the doping of TiO2 can help TiO2 absorb a part of visible light, which hinders the photo-generated electron hole pair (e-r / h) of TiO2, which further improves the photoresponse of the electrode to visible light. A photochemical sensor for quantitative determination of hydroquinone was constructed. The linear response range was from 4.0 ~ 10 ~ (-7) mol ~ (-1) to 3.0 ~ (-1) ~ 10 ~ (-5) mol L ~ (-1). The detection limit (3S/N) was 9.8 ~ (-8) mol L ~ (-1). The sensor has been successfully used to determine the degradation rate of hydroquinone.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;O657.1
[Abstract]:In this paper, CdS quantum dots TiO2 and other nanomaterials were prepared and combined with graphene or hemin, respectively. A novel photoelectric / electrochemical sensor with high catalytic performance was constructed. The surface morphology, structure, optical and electrochemical properties of the nanocomposites were characterized by Fesemer XRDX UV-Visand electrochemical detection. A novel photoelectric / electrochemical sensor was applied to the sensitive detection of environmental pollutants and H2O2. The photovoltaic behavior and catalytic mechanism of p-phenylenediamine were studied. The main contents include the following two aspects: 1. In this part, water-soluble CdS quantum dots were synthesized by hydrothermal method. CdS-GS/FTO film modified electrode was prepared by doping proper amount of graphene (GS). The photochemical properties of CdS quantum dot films are greatly improved by the doping of graphene. Under visible light irradiation, the cyclic voltammogram of p-phenylenediamine (PPD) on CdS-GS/FTO presents a "S" shape due to the existence of photocatalytic reaction, which is used to optimize the ratio of membrane materials. The effects of scanning rate and pH on the photovoltaic behavior of PPD show that, although the control steps of the electrochemical process have not changed under light irradiation, more electrons than the number of protons may be involved in the photocatalytic process. In addition, photoactive membrane modified electrodes are used for sensitive detection of p-phenylenediamine. Under the optimum conditions, the linear response range of the photochemical sensor to PPD is 1.0 脳 10 ~ (-7) ~ 3.0 ~ (-1) mol ~ (-6) mol L ~ (-1) and the detection limit (3S/N) is 4.3 ~ (-8) mol / L ~ (-1). In this part, photoinduced electron transfer of PPD on the electrode was studied by photovoltaic method, and a photochemical method of PPD sensitive detection was proposed. The TiO2 nanoparticles were prepared by flame aerosol synthesis technology and combined with hemin (Hemin). Two functional Hemin-TiO2/GCE electrodes with electrocatalytic activity and photovoltaic activity were prepared. Cyclic voltammetry analysis showed that a pair of redox peaks of Hemin appeared clearly on Hemin-TiO2 composite film. The effects of scanning rate and pH of electrolyte on electrochemical behavior of modified electrode. Hemin-TiO2 / GCE-modified electrode had good electrocatalytic reduction activity to H2O2. There was a good linear relationship for H2O2 in the range of 3.0 ~ 10 ~ (-7) mol ~ (-1) to 4.7 ~ (-4) mol L ~ (-1). The detection limit (3S/N) was 7.2 ~ (-8) mol L ~ (-1). At the same time, the doping of TiO2 can help TiO2 absorb a part of visible light, which hinders the photo-generated electron hole pair (e-r / h) of TiO2, which further improves the photoresponse of the electrode to visible light. A photochemical sensor for quantitative determination of hydroquinone was constructed. The linear response range was from 4.0 ~ 10 ~ (-7) mol ~ (-1) to 3.0 ~ (-1) ~ 10 ~ (-5) mol L ~ (-1). The detection limit (3S/N) was 9.8 ~ (-8) mol L ~ (-1). The sensor has been successfully used to determine the degradation rate of hydroquinone.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;O657.1
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