| Phenolic compounds including phenol and its derivatives are priority pollutants released into the environment.Conventional methods are hard to meet the growing demand for phenolic wastewater treatment.Owing to its strong oxidizing capability,easy operation and environmental benign,electrochemical advanced oxidation process is one of the most promising methods for refractory pollutant treatment.The preparation of anode material and the research on catalytic mechanism are the key issues in this field.Traditional 2D PbO2electrode has disadvantages of low specific surface area,low catalytic efficiency,poor electrode stability and high energy consumption.In this thesis,three-dimensional Carbon Felt/PbO2（CF/PbO2）and Porous Ti/TiO2-NT/SnO2-Sb/PbO2 electrodes with high catalytic efficiency,long-term stability and much lower energy consumption were prepared,and the electrocatalytic oxidation mechanism of phenol was investigated by in-situ ATR-FTIR.The content of this thesis contains the following three parts.Porous Ti/TiO2-NT/SnO2-Sb/PbO2 electrode was prepared based on porous Ti substrate.It demonstrated that the introduction of TiO2-NT lead to a more complete and uniform SnO2-Sb interlayer,and the accelerated electrode life was improved by 6.7 times.The deposition time had a great effect on the morphology of PbO2 active layer,and the electrode prepared under the optimal deposition time（60 min）was beneficial for obtaining a 3D structure and complete PbO2 active layer,which demonstrated a larger electrochemical active surface area（q*T improved 4.2 times）,lower charge transfer resistance and 20%improved efficiency on phenol removal.CF/PbO2 electrode was prepared through electrodeposition method based on carbon felt substrate.The active layer of CF/PbO2 electrode was uniform and no obvious cracks.Compared with traditional Ti/SnO2-Sb/PbO2 electrode,the CF/PbO2 electrode had excellent electrochemical performance and demonstrated a higher phenol removal efficiency（first-order kinetics constant improved 11 times）,higher COD removal efficiency and lower energy consumption which was attributed to the large generation capacity of·OH and strong adsorption ability.The in-situ infrared spectra during phenol electrocatalytic process was acquired on a special in-house built in-situ spectroelectrochemistry platform.Through the analysis of spectra,the surface adsorption and degradation process of phenol during electrocatalytic oxidation were explored.The generation and evolution of surface passivation were also investigated.Combined with GC-MS and HPLC results,a more detailed scenario of in-situ surface process was revealed,in addition to deeper understanding of degradation pathway of phenolic compound.This study provided a new strategy for the fabrication of highly active and stable three-dimensional electrode.It also demonstrated a novel in-situ spectroelectrochemistry characterization method to shed light on the surface process that are not accessible with conventional characterization method.This study would provide experimental and theoretical support for development of novel highly active electrode for electrocatalytic wastewater treatment. |
