Effect Of Process Parameters On The Electrochemical Oxidation Performance Of Diamond Film

Boron-doped diamond thin films as a new p-type semiconductor material,is used as the anode material scientists applied electrochemistry.The diamond crystal structure as well as its characteristics is affected by the technological conditions in diamond film preparation.The P-type boron-doped diamond?BDD?thin film electrode was prepared on tantalum substrate by the hot filament chemical vapor deposition?HFCVD?technique.The effects of different technological conditions on the surface morphology and the quality of diamond thin film were studied by atomic force microscopy?AFM?,scanning electron microscope?SEM?,X-Ray Diffraction?XRD?.The effects of boron doping concentration on resistivity of diamond thin film were studied by four point probe technology.The effects of different electrolyte on electrochemical characteristics of BDD electrode were studied by cyclic voltammetry?CV?.The ability of different boron doping concentration on catalytic oxidation phenol of BDD electrode was researched by using phenol simulating industrial wastewater.Experimental results show that:?1?During the preparation of diamond films,the carbon source concentration affect the nucleation density and diamond purity.The diamond growth rate is low,and it is difficult to form a large area of diamond film under lower carbon source concentration.The diamond growth rate increases obviously,but it also produces a lot of graphite at the same time under higher carbon source concentration.So it is concluded that the best carbon source concentration is 1.5%.The sample is studied by cyclic voltammetry in different pH value electrolyte,it is concluded that the sample has the widest potential window in the H₂SO₄ solution.?2?Chamber pressure can affect the surface morphology and structure of diamond.It is advantageous to the growth of diamond?220?crystal surface but the diamond nucleation density is low under lower deposition chamber pressure.The diamond films growth rate decreases,the nucleation density increases,it is easy to grow spherical diamond films under a higher deposition chamber pressure.It is concluded that the diamond grain size is larger,the thin film thickness reaches a maximum value of 3.25 microns,and the oxygen evolution potential reaches the maximum value of2.5V in the H₂SO₄ electrolyte when the deposition chamber pressure is 4kPa.?3?The substrate temperature can affect the diamond surface morphology mainly,the diamond grain is pyramid shape,the electrochemical window of the sample reaches a maximum value of 4.0V in H₂SO₄ solution when the substrate temperature is 750?.?4?The boron doping can refine the crystal grain,but excess boron doping can also cause the diamond structure defects,when the boron doping concentration is 10000ppm,the grain shape is complete,the resistivity of diamond thin film reached a lowest of 0.0098??cm,and the diamond electrode reached the widest potential window in H₂SO₄ solution;the phenol oxidation peak current density reached a maximum of 0.0035A?cm^-2,the half peak width is the most narrow,and the efficiency of oxidation phenol is the highest in 0.1mol/L phenol+1mol/L H2SO4 solution,it is beneficial to improve the catalytic efficiency of organic pollutants,and reduce the energy consumption.