Preparation And Electrocatalytic Properties Of Carbon Cloth Based Micro Nano Electrode

With the rapid expansion of science and technology,the urbanization process is accelerating,and the water pollution caused by industrial production has raised huge damage to the environment.At present,there are many technologies for the detection,treatment and protection of water environmental pollutants,and most of them use a combination of physical,chemical and biological treatment modes.With the proposal of“green chemistry and clean environment”,it is very important to realize the detection and treatment of environmental pollutants with low energy consumption,low cost and environment-friendly reaction.Due to its advantages of simple operation,good controllability,no secondary pollution and mild reaction conditions,electrochemical method could achieve the green environmental protection.Therein,as the core part of electrochemical technology,the design and construction of electrodes play a decisive role in the detection and degradation of pollutants.Although synthesis of multi-level composite micro-nano materials with high catalytic performance has been widely studied.It’s poor stability,easy to break off,low binding force between a substrate and active materials and complex preparation process are exhibited due to its powder material state.Therefore,the development and construction of self-supporting micro-nano electrodes,leading to the in-situ growth of active materials on conductive substrates,could solve the limitations of powder catalyst electrode preparation and enhance the bonding force between electrode active materials and conductive substrates,which is beneficial to the fast electron transport for reactions.In this thesis,carbon cloth is used as a conductive substrate,and a simple electrochemical deposition method is used to control the structure composition and surface morphology of carbon cloth-based micro-nano electrodes by regulating the deposition potential and current.The influence of the structure,composition and morphology of carbon cloth-based micro-nano electrodes on the electrocatalytic performance was explored,thus laying a foundation for the application of carbon cloth-based micro-nano electrodes in the detection and treatment of environmental pollutants.The main contents of research are as follows:（1）Application of carbon cloth-based dendritic Pb O₂electrodes in H₂O₂electrochemical sensingPb O₂was directly grown on the surface of carbon cloth substrate by electrochemical deposition.The carbon cloth supported dendritic Pb O₂electrode（CC-dendritic Pb O₂）and aggregated Pb O₂electrode（CC-agglomerated Pb O₂）were obtained by controlling the deposition methods and conditions,which were used as the electrodes for H₂O₂electrochemical sensing.The experimental results exhibit that the three-dimensional network structure of carbon cloth provides a framework for the electrochemical deposition of active materials,leading to a large electrochemical active area of the carbon cloth-based dendritic Pb O₂electrode.As the working electrode of the electrochemical sensor,it has good electrochemical catalytic activity and good selectivity for H₂O₂,its linear response range is5×10^-6-1.19×10^-2M,and the detection limit is 0.781μM（S/N=3）.In addition,the H₂O₂electrochemical sensor constructed based on the CC-dendritic Pb O₂electrode can also realize the detection of H₂O₂in actual environmental water samples.（2）Study on the selective electrochemical reduction of nitrate by carbon cloth-based Cu/Pt bimetallic nanostructured electrodesThe improvement of electrode interface selectivity and the enlargement of electrode specific surface area are the key factors to achieve high-efficiency electrocatalytic performance.To this end,platinum nanoflowers（Pt-NFs/CC）with a larger specific surface area and a preferential（100）crystal plane growth orientation were prepared on a carbon cloth substrate by a potentiostatic deposition method,and then copper was adsorbed on the surface to obtain a Cu/Pt bimetallic nanostructured electrodes（Cu/Pt-NFs/CC）for electrochemical reduction of nitrate.The experimental results show that the three-dimensional network structure of carbon cloth provides a prerequisite for the exposure of large-area Pt（100）crystal planes,which is conducive to the adsorption of Cu at its interface,thus enabling the selective reduction of nitrates.It is found that the Cu/Pt-NFs/CC electrode with 8.75%Cu coverage has high selectivity for the electrochemical reduction of nitrate to nitrogen.In this process,NO₃^-will be preferentially adsorbed on the surface of Cu for electrochemical reduction,and the intermediate product NO₂^-will be adsorbed on the（100）crystal plane of Pt-NFs,resulting in the generation of final product N₂by the NO₂^-selective reduction and NH₃oxidation.In addition,the coverage of Cu on the surface of Pt-NFs has a great influence on the electrocatalytic activity and selectivity of nitrate,the electrocatalytic activity of nitrate decreases with the increase of Cu coverage.