Preparation of Electrochemical Sensor Based on RGO-Au-ZIF-8 Composite and Its Application in Simultaneous Detection of Lead Ions and Copper Ions

Abstract

Metal organic frameworks (MOFs) have unique advantages in adsorption and preconcentration of heavy metal ions due to their structure and composition characteristics, which make them show great potential in optical sensing of heavy metal ions. However, their applications in the field of electrochemical sensing is greatly limited because of their poor conductivity. In this work, a functionalized MOF composite, thermally reduced graphene oxide-Au nanoparticles-zeolitic imidazolate skeleton material (RGO-Au-ZIF-8), was fabricated. It exhibits much improved electrochemical properties compared with the pristine MOF. A novel electrochemical sensing platform was constructed based on it, and simultaneous detection of lead ions (Pb 2＋) and copper ions (Cu 2＋) in aqueous solution was realized. Specifically, the Au-ZIF-8 was prepared by adding polyvinylpyrrolidone (PVP)-stabilized Au nanoparticles (AuNPs) to the reaction solution of ZIF-8. The modification of AuNPs effectively improved the conductivity of the material. After compounding with RGO, the RGO-Au-ZIF-8 composite was prepared. The RGO was used as scaffold for the Au-ZIF-8 in the composite to increase the effective surface area of electrode and improve conductivity. The morphology and structure of the prepared materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-visible absorption spectroscopy (UV-Vis). The electrochemical properties of the modified electrodes were characterized by various electrochemical techniques. The experimental parameters, such as pH value of working solution, accumulation potential, accumulation time and composition ratio of Au-ZIF-8 to RGO were optimized. Under the optimized conditions, simultaneous and sensitive detection of Pb 2＋ and Cu 2＋ on the prepared electrochemical sensor was realized with the detection limits of 2.6×10-9 and 7.8×10-9 mol•L-1 for Pb 2＋ and Cu 2＋ , respectively (S/N＝3). The interference test showed that the electrochemical sensor has good selectivity for the detec

ZIF-8-doped Au/PEDOT nanocomposite as an effective electrochemical sensing platform for simultaneous detection of catechin and sunset yellow in tea beverage

“…Lu et al improved the conductivity of ZIF-8 by introduced the Au NPs, and this sensor platform had successfully detected dopamine (Lu et al, 2020). Sun and her partners developed an electrochemical sensing platform based on the reduced graphene oxide (rGO)-Au-ZIF-8 composite, which performed high sensitivity and selectivity toward lead ions and copper ions detection (Sun et al, 2020). To further improve the electrochemical properties, the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) was introduced as the support to stabilize Au NPs, because of its high electrical conductivity, easy-fabrication, and the strong interaction between the S atoms of the thiophene ring and Au NPs (Xu et al, 2010).…”

Fe-Hemin-Metal Organic Frameworks/Three-Dimensional Graphene Composites with Efficient Peroxidase-Like Bioactivity for Real-Time Electrochemical Detection of Extracellular Hydrogen Peroxide

“…[23][24][25] The three-dimensional graphene (3DG), which is composed of self-assembling 2D graphene sheets, has been used as a unique conducting additive for sensor applications due to the three-dimensional network structure with high specific surface area and rapid charge transfer. 26,27 The introduction of 3DG can not only facilitate the electron transport between catalysts and small molecules, but also prevent the aggregation of active materials, thereby further increasing catalyst durability and structural stability.…”

Water Adsorption Properties and Applications of Stable Metal-organic Frameworks

“…作为一种多孔结晶材料, MOFs 材料具有丰 富的孔道结构、超高的比表面积(最高可达 7839 m 2 • g -1 )、低密度性(可低至 0.13 g•cm -3 )以及无机构筑单元 和有机配体设计组合的多样性 [1][2][3][4] . 这些特点使得 MOFs 材料在气体吸附与分离 [5][6][7][8][9][10] 、能源气体储存与转化 [11][12][13][14] 、 催化 [9,[15][16][17][18][19][20] 、环境污染物控制 [21][22][23][24][25][26][27] 、传感检测 [28] 等领域 展现出潜在的应用价值. 然而在上述吸附、分离与催化…”