Study On The Construction And Performance Of Electrochemical Sensor Based On Hydrotalcite/Carbon Nanotubes

Electrochemical sensors show the characteristics of high sensitivity,fast response,simple equipment and easy miniaturization.They have received extensive attention in the fields of environmental monitoring,pesticide residue analysis,and food industry.Designing and preparing new nanomaterials and using them as electrode materials for electrochemical sensors is essential to improve the sensitivity of the sensor,lower the detection limit,and broaden the field of sensor application.In this paper,respectively with Ni Co Al hydrotalcite/multi-wall carbon nanotubes?Ni Co Al-LDH/MWCNT?,Ni Co Al oxide/multi-wall carbon nanotubes?Ni Co Al-LDO/MWCNT?and Ni Co Al hydrotalcite/multi-wall carbon nanotubes/Ag?Ni Co Al-LDH/MWCNT-Ag?as the electrode materials to construct an electrochemical sensor,which realized hydroquinone?CC?,hydroquinone?HQ?,bisphenol A?BPA?and nitrite ion?NO₂^-?fast,highly selective and highly sensitive detection,respectively.The main research contents of this paper were as follows:Ni Al-LDH/MWCNT,Co Al-LDH/MWCNT and Ni Co Al-LDH/MWCNT composite materials were prepared by one-step hydrothermal method and applied to the simultaneous detection of HQ,CC and BPA.It was found that Ni Co Al-LDH/MWCNT exhibited higher electrochemical activity for HQ,CC and BPA than Ni Al-LDH/MWCNT and Co Al-LDH/MWCNT.The synergistic effect of Ni Co Al-LDH and MWCNT made the modified electrode had good electrocatalysis for the oxidation of HQ,CC and BPA.Ni Co Al-LDH/MWCNT modified electrode had the best selectivity and highest sensitivity when detected HQ,CC and BPA simultaneously.The sensor constructed by Ni Co Al-LDH/MWCNT composite material had good anti-interference,stability and reproducibility,and the linear ranges of HQ,CC and BPA detection were 1.5?600,1.5?1030 and 0.01?250?mol·L^-1,respectively.The detection limits were 0.4,0.8 and 0.006?mol·L^-1?signal-to-noise ratio S/N=3?,which can be used for the detection of HQ,CC and BPA in actual samples.Ni Co Al-LDH precursor was prepared by one-step hydrothermal method,and Ni Co Al-LDO was obtained by calcination,and then mixed with MWCNT to obtain Ni Co Al-LDO/MWCNT mixtures,which were applied to the simultaneous detection of HQ,CC and BPA.And investigated the effect of calcination temperature on the electrochemical performance of Ni Co Al-LDO/MWCNT.The study found that when Ni Co Al-LDH was calcined at 400?C,the Ni Co Al-LDO/MWCNT₄produced had the highest electrochemical activity,and the sensor constructed by it showed the best selectivity and the highest sensitivity when detecting HQ,CC and BPA simultaneously.Ni Co Al-LDO/MWCNT₄had good anti-interference,stability and reproducibility.The linear ranges for HQ,CC and BPA were 1.5?625.5,0.75?690 and0.005?370.55?mol·L^-1,respectively,and the detection limits were 0.20,0.25 and0.0023?mol·L^-1?signal-to-noise ratio S/N=3?,which could be used for HQ,CC and BPA detection in actual samples.Ni Co Al-LDH/MWCNT-Ag composites were prepared by in-situ reduction method and used to construct NO₂^-electrochemical sensors to explore the loading of Ag nanoparticles?Ag NPs,Ag/Ni Co Al-LDH mass ratio?on their electrochemistry effect of activity.The results showed that when the mass ratio of Ag/Ni Co Al-LDH was 30%,the obtained Ni Co Al-LDH/MWCNT-Ag₃had the highest electrochemical activity,and the sensor constructed by it has good anti-interference,stability and reproducibility.The detection linear range was 0.25?4000?mol·L^-1,and the detection limit was 0.06?mol/L?signal-to-noise ratio S/N=3?,which couid be used for NO₂^-detection in actual samples.