Preparation Of Cu And Pd/Cu Nanowire Electrodes And Their Performance As Electrochemical Sensor For Detection Of 4-nitrophenol

4-Nitrophenol has become one of important pollutant in water because it is commonly used in industrial production and difficult to decompose in nature.Researchers have already build electrochemical sensors to detect 4-nitrophenol in water,where the electrode materials are mainly noble metals such as Au and Ag.While Cu materials has occationally been used in the detection of 4-nitrophenol,the reported Cu-based sensor has a poor performance and cannot achieve both high sensitivity and wide linear range.To solve these problems,we have prepared Cu free-standing electrodes using self-made copper nanowires and use them for sensoring 4-nitrophenol.Meanwhile,to achieve superior sensing performance,Pd nanoparticles are uniformly coated on the surface of Cu free-standing electrodes via low-temperature displacement reaction.Our main works are summarised as follows:Cu nanowires with uniform thickness were prepared by a simple solution reduction method and its membrane with a size of 0.5×0.6×0.05 was produced by a template method.Cu nanowire free-standing electrodes with porous network structure were obtained by calcinating the copper membrane at 600?.The reductive reaction process of 4-nitrophenol on Cu nanowire electrode was studied by CV,and the effects of electrolyte concentration,pH,and scanning rate on the sensing performance were investigated by LSV.CV,DPV and i-t mesthods were employed to measure its sensing performance.A excellent performance of Cu nanowire free-standing electrode were observed by CV with a high sensitivity?4.831?A/?M?,wide linear range?4-2200?M?and low detection limit?1?M?.The performance of Cu nanowire free-standing electrode were much better than that of self-made Cu nanowire-modified electrode?CuNW/GCE?.EIS curves showed that the charge transfer resistance of free-standing electrode is much smaller than that of modified electrode.The Cu nanowire free-standing electrode shows good stability,high selectivity and also shows a great accuracy in testing real water samples.The freezing point of PdCl₂ solution was lowered by adding salt into the solution,and Pd/Cu materials was obtained by dispesing copper nanowire into the above solution at low temperature.The effects of temperature on reaction rate were investigated and TEM was used to characterize the morphology of Pd/Cu material prepared at different temperatures.It was found that the most of Pd/Cu nanoweires prepared at-7?own a solid structure,rather than a hollow one,and Pd nanoparticles are distributed more homogenously.The Pd/Cu electrode was obtained by dipping Cu nanowire electrode into PdCl₂solution at-7?,by which Pd nanoparticles are decorated on its surface via displacement reaction,and then its performance for sensing 4-nitrophenol was investigated by LSV.Pd/Cu electrode showed an excellent performance in sensoring4-nitrophenol with a sensitivityof 8.8?A/?M,a linear range of 2⁵600?M and a detection limit of⁰.55?M.When detecting 4-nitrophenol in both river water and laboratory water,the Pd/Cu electrode prepared at a temperature of-7?exhibited a similar result in compared with that obtained by spectrometetry.It also showed a good perfermance in real sample detection with recoveries ranging from 97.2% to 101.0%.