Diamond Electrodes: Preparation And Application For Electrochemically Detecting Aniline

As the hardest substance in nature,diamond has a series of excellent physical and chemical properties,such as ultra-wide band gap,high thermal conductivity,high electron（hole）mobility,etc.It is used for many fields such as machinery,electronics,aerospace and so on.Conductive diamond can be used as electrode material by doping.Due to the inherent excellent properties of diamond,such as good chemical inertness,wide electrochemical potential window,easy surface functionalization,high mechanical strength,etc.,it has become one of the extraordinary materials for high-performance electrochemical electrodes.Diamond has a wide range of applications in the trace detection of pollutants.In this paper,boron-doped diamond（BDD）and boron/nitrogen co-doped diamond（BND）films were prepared on a single crystalline silicon substrate by chemical vapor deposition technique.The basic properties of BDD and BND were studied and compared.BDD and BND were applicated to the electrochemical quantitative detection of aniline.We analyzed the electrochemical detection mechanism of aniline,and the practical application of the BND sensor was tested.The main results are listed as follows:（1）The BDD and BND electrodes were prepared by microwave plasma chemical vapor deposition method.We have studied and compared the morphology,quality and properties of BDD and BND electrodes.We also analyzed the effect of boron doping and boron/nitrogen co-doping on diamond films.These results will be helpful to the further research,development and application of conductive diamond.（2）The concentration of aniline samples was measured in the p H 2.0 phosphate buffer solution.The conductive BDD and BND films were used as the working electrodes for quantitative detection of aniline.The BND electrode is obviously better than the BDD electrode in detecting aniline.Compared with the BDD electrode,the BND electrode has a wider electrochemical potential window,the electrode is more sensitive,and the lower electrochemical impedance means the faster electron transfer speed.The excellent properties can be attributed to the synergistic effect of boron and nitrogen.Meanwhile,a wide linear detection range(0.5-500μmol L^-1)of detecting aniline is achieved on BND electrode,which is five times larger than that of BDD electrode(1μmol L^-1-100μmol L^-1).The detection range was significantly wider with respect to the previous reports with various electrochemical electrodes.The BND-based sensors are of stability,reproducibility,and usability.The BND electrode is suitable for detecting various substances with high sensitivity.In this paper,two conductive diamond film electrodes（BDD and BND）are fabricated.The BND electrode has achieved important results in the quantitative detection of aniline.It has been proved that the electrode has extremely high stability and strong anti-scaling ability.The BND provides a novel diamond-based sensors to detect various substances with high sensitivity for environmental pollution detection and monitoring.