Modification Of Ti Electrode For Electrochemical Reduction Of CO₂ To CH₃OH

The rate of producing CO₂has far exceeded the rate of CO₂which naturally enter plants and soil and be converted into fossil fuels.It causes serious environmental problems.It is urgent to use modern science and technology to reduce CO₂concentration and achieve sustainable development.It also responds to the concept of"carbon neutrality"proposed by China.Among all kinds of methods to degrade carbon content,electrochemical CO₂reduction reaction has been widely used because of its environmental friendliness and convenient operation,especially its advantages of being able to choose different reaction products by changing the applied potential.By referring to the literatures on the influencing factors of electrochemical reduction of CO₂,the advantages and disadvantages of different electrode materials,electrolytes and other electrolytic conditions were analyzed.On this basis,the treatment and modification of titanium metal as the cathode of electrochemical reduction of CO₂was explored.The influence of electrochemical reduction of CO₂behavior was researched in this thesis.Firstly,the pure Ti electrode,acid-H₂O₂treated Ti electrode,acid-base treated Ti electrode and oxalic acid treated Ti electrode were used as work electrode（cathode）,respectively,Pt electrode was as the auxiliary electrode（anode）,the calomel electrode was as reference electrode,and the behaviors of electrochemical reduction of CO₂in different concentrations of potassium bicarbonate solution were researched.The results showed that the electrolysis effect of the modified Ti electrode was better than that of the untreated pure Ti electrode.Therefore,the research experiments mainly focused on the modified Ti electrode as the working electrode（cathode）.The experimental results showed that the titanium electrode treated with oxalic acid had better results.The Faraday efficiency of CH₃OH produced by electrolysis reached at45.83%in 0.5 mol·L^-1potassium bicarbonate solution when the electrolysis voltage was-1.4V_vs.SCEand electrolysis time was 3 hours.The current did not obviously change after electrolysis for 10 hours.it indicated that the electrode stability was good.Secondly,the influence of Ni supported Ti O₂electrode and Ni supported Mo doped Ti O₂electrode as cathode on electrochemical reduction of CO₂was investigated.Using platinum electrode as anode and calomel electrode as reference electrode,the electrochemical reduction behavior of CO₂in different concentrations of potassium bicarbonate solution was researched.The experimental results showed that the nickel-supported Mo doped Ti O₂electrode as the working electrode had good results.The Faraday efficiency of CH₃OH produced by electrolysis reaches at18.26%in 0.5 mol·L^-1potassium bicarbonate solution when the electrolytic voltage was-1.1 V_vs.SCEand the electrolytic time was 3 hours.The electrode stability was well.Finally,the surface morphologies of pure titanium electrode and treated and modified titanium electrode were observed and analyzed by SEM.It indicated that the titanium electrode treated by different methods had different degrees of roughness and depression.The element characterization of nickel supported Mo doped Ti O₂electrode was carried out by EDS and XRD technology and it indicated that molybdenum was successfully doped into titanium dioxide.