The Construction Of An Electrochemical Sensor Based On Carbon Nitride And Its Application In Electrochemical Detection

Electrochemical sensor based on nanomaterials have been extensively used in many fields due to convenient operation,high measuring accuracy and rapid response,for instance safety detection,environmental monitoring and food analysis etc.The introduction of nanomaterials can improve the performance of electrochemical sensor.As a metal-free and nontoxic semiconductor,Graphitic carbon nitride?g-C₃N₄?has attracted a great deal of research interest in the field of electrochemistry due to good biocompatible and chemical stability.Unfortunately,a single g-C₃N₄ will be re-decomposed in application,greatly reducing their application performance,so it is critical to modify the g-C₃N₄.In this paper,the g-C₃N₄ is used as the base material,precious metal materials?such as Au and Pt?and inorganic metal ions are introduced to prepare nanocomposites.A novel sensor was constructed by modifying carbon paper?CP?with synthetic material the electrochemical performance of the sensor for the detection of phenol was investigated.The specific work is as follow:First,the g-C₃N₄ was synthesized by high-temperature sintering,then the g-C₃N₄was treated via cetyltrimethylammonium bromide?CTAB?,finally Na⁺was doped into the g-C₃N₄ via simple hydrothermal method,Na⁺dopped g-C₃N₄ composite were successfully prepared,and dropped onto the carbon paper?CP?surface,the direct electrochemical behavior of phenol was detected.The morphological characteristic of nanocomposite was analyzed by scanning electron microscopy?SEM?and transmission electron microscopy?TEM?,the chemical composition of the obtained sample was determined using energy dispersive spectroscopy?EDS?.Cyclic voltammetry?CV?experimental result shows that the oxidation peak currents linearly increased with phenol over the range of 0?M to 110?M,a detection limit of 0.33?M was obtained.The sensor demonstrated a wide linear range and high sensitivity.The gold/graphitic carbon nitride?Au/g-C₃N₄?composite was prepared by the precipitation reducing method and used to construct a novel Au/g-C₃N₄/GCE electrochemical sensor by modifying carbon electrode?GCE?.Cyclic voltammetry?CV?and electrochemical impedance spectroscopy?EIS?were applied to study the electrochemical properties of the sensor,and the ideal result was acquired.The current response of Au/g-C₃N₄/GCE sensor was discussed by chronoamperometry?CA?when the concentration of phenol was low,the result displayed that the linearity between the oxidation peak currents and the concentration of phenol in the range of 1?M to 10?M,the linear correlation coefficient is 0.9987.In this chapter,platinum/carbon nitride?Pt/g-C₃N₄?nanocomposites are prepared by polymerizing metal Pt onto the surface of the g-C₃N₄,a simple sensor was constructed with the prepared nanomaterials.Under the optimum experimental conditions,the oxidation peak currents increased linearly with phenol concentration in the range of 2?M-20?M,the sensitivities of this electrochemical sensor in the linear range was calculated to be 0.667?M.The selectivity of the sensor was evaluated by chronoamperometry?CA?,the experimental results demonstrate that the sensor exhibits high electrocatalytic activity and good selectivity.In the last part,a novel Au/CeO₂/g-C₃N₄ composite was synthesized by simple hydrothermal method,high resolution transmission electron microscopy?HR-TEM?reveals that the lattice fringes and structure of the composite.An electrochemical sensor for determination of phenol was designed based on Au/CeO₂/g-C₃N₄nanocomposite modified carbon paper?CP?.The electrochemical behavior of phenol at Au/CeO₂/g-C₃N₄/CP electrodes was investigated via cyclic voltammetry?CV?and electrochemical impedance spectroscopy?EIS?.The results demonstrate the proposed sensor could precisely measure phenol with a linear range of 10?M-90?M and a detection limit of 0.1?M?S/N=3?.In addition,anti-interference ability of Au/CeO₂/g-C₃N₄/CP was tested by chronoamperometry?CA?,the experimental results demonstrate the electrode has strong anti-interference ability.The sensor has high accuracy and selectivity and can be successfully applied to the quantitative detection of phenol.