铜纳米粒子/聚丙烯酸/石墨烯纳米复合材料修饰玻碳电极检测水中的4-硝基苯酚

Copper Nanoparticles/Poly Acrylic Acid/Reduced Graphene Oxide Nanocomposite Modified Glassy Carbon Electrode for Determination of 4-Nitrophenol in Water

采用一种温和且简单的原位生长法将铜纳米粒子和石墨烯非共价键合,得到铜纳米粒子/聚丙烯酸/石墨烯(Cu NPs/PAA/GR)纳米复合材料,对4-硝基苯酚(4-NP)表现出良好的电催化活性。用扫描电镜对此纳米复合材料的形貌进行了表征。以此材料修饰的玻碳电极受吸附控制,4-NP在该电极表面的反应机理为两电子转移过程,电子转移数n=2.3,修饰电极的有效面积为0.6275 cm2,是裸电极的2.22倍,电极吸附量Гs为1.6×10!11mol/cm2,催化速率常数kcat的平均值为1.15×104L/(mol/s)。修饰电极的响应电流与4-NP的浓度在1~150μmol/L范围内呈良好的线性关系,线性方程为:Ipa(μA)=!0.015C(μmol/L)-0.98,(R2=0.9951),检出限为0.23μmol/L(S/N=3)。此传感器制备简单、灵敏性高、稳定性和重现性好。使用此传感器检测实际水样中4-NP的回收率为88.6%~100.7%,相对标准偏差为2.6%~5.9%。

A moderate and simple in situ growth approach was employed to load copper nanoparticles（Cu NPs） noncovalently on graphene for preparation of Cu NPs/poly acrylic acid/reduced graphene oxide（Cu NPs/PAA/GR） nanocomposites for electro-catalysis of 4-nitrophenol（4-NP）.The morphology of the material was observed by scanning electron microscopy（SEM）.Tests with various scan rates and p H conditions indicated an adsorption-controlled electrode process occurred.The mechanism of the electrode reaction of 4-NP involved a two-electron process accompanied by a deprotonation step.Electrochemical parameters were calculated with the electron transfer number（n） as 2.3,the effective area（0.6275 cm^2） of Cu NPs/PAA/GR/GCE electrode was 2.22 times as large as that of bare electrode,the adsorption capacity Гs value was 1.6 ×10^-11mol/cm^2,and the average value of the calculated kcatvalue was 1.15 ×10^4L/（mol·s）.Under the optimal conditions,the differential pulse voltammetric response of the electrode showed a linear relationship with 4-NP concentration in the range of 1-150 μmol/L.The regression equation was Ipa（μA） =-0.015C（μmol/L）-0.98（R^2= 0.9951）,and the detection limit was 0.23 μmol/L（S/N = 3）.The fabricated sensor exhibited high sensitivity,good stability and high reproducibility.This sensor was applied for detection of 4-NP in water samples with favorable recoveries of 88.6%-100.7% and relative standard deviation（RSD） of 2.6%-5.9%.