CAJ | 학술논문

在水溶液中,电还原CO2制取CO时,电极易中毒失活,采用扫描电子显微镜(SEM)、X 射线光电子能谱(XPS)对反应前后的电极材料进行检测,研究CO2在KHCO3水溶液中发生电化学还原反应时,Au电极失活原因及电极材料活性降低对反应过程的影响.结果表明,电极表面吸附了一层黑色有害物质.这层黑色有害物质大部分是石墨碳,并有微量的铁和锌.采用塔菲尔曲线、电化学阻抗(EIS)、线性扫描曲线、恒电位电解和气相色谱法等研究了有害物质对CO2电还原反应动力学过程的影响,发现随着反应的进行,生成CO的平衡电位负移,电荷转移电阻增大,交换电流密度变小,产物CO的电流效率迅速降低.说明电极表面附着的有害物质使电极材料活性降低,阻碍了CO2电还原反应的进行.
재수용액중,전환원CO2제취CO시,전겁역중독실활,채용소묘전자현미경(SEM)、X 사선광전자능보(XPS)대반응전후적전겁재료진행검측,연구CO2재KHCO3수용액중발생전화학환원반응시,Au전겁실활원인급전겁재료활성강저대반응과정적영향.결과표명,전겁표면흡부료일층흑색유해물질.저층흑색유해물질대부분시석묵탄,병유미량적철화자.채용탑비이곡선、전화학조항(EIS)、선성소묘곡선、항전위전해화기상색보법등연구료유해물질대CO2전환원반응동역학과정적영향,발현수착반응적진행,생성CO적평형전위부이,전하전이전조증대,교환전류밀도변소,산물CO적전류효솔신속강저.설명전겁표면부착적유해물질사전겁재료활성강저,조애료CO2전환원반응적진행.
The working electrode might get inactivate easily in the process of electrochemical reduction of CO2 to CO in aqueous solution. The effects of the deactivation reasons of the Au electrode and the decrease of electrode activity on the reaction during the electrochemical reduction of CO2 in KHCO3 aqueous solution, and the surface of Au electrode were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS).The results showed that a small amount of impurities composed of C graphite and a little of Fe and Zn adsorbed on the surface of the Au electrode. The electrochemical kinetic characteristics of CO2 reduction on Au electrode were studied using Tafel curve, Electrochemical impedance spectroscopy(EIS), Linear sweep curve, Potentiostatic electrolysis, and gas chromatographic. As a result, with the reaction going on, the equilibrium potential of CO2 conversion to CO shifted to negative, the electron transfer resistance rised up, the exchange current density reduced continuously, and the faradaic efficiency of CO decreased rapidly, which indicated that C graphite and metal adsorbed on the electrode decreased the electrocatalytic activity of Au electrode, and hindered the CO2 reduction.