Cu_2O/TNTs电极的制备及其光电催化还原CO_2合成甲醇研究

Preparation of Cu_2O/TNTs electrode and its photoelectrocatalytic performance for the reduction of CO_2 to methanol

以钛阳极氧化制备的TiO_2纳米管(TNTs)阵列为载体,采用脉冲电沉积法将Cu_2O沉积到TNTs的管壁上,制备了Cu_2O/TNTs电极。采用扫描电镜(SEM)、透射电镜(TEM)以及X射线光电子能谱(XPS)对电极的形貌以及沉积物价态进行了表征。通过循环伏安、光电流-时间曲线测试,研究了沉积电位以及沉积电量对电极光电催化性能的影响。结果表明:脉冲电沉积的沉积物为Cu_2O纳米颗粒。制备的Cu_2O/TNTs电极光电活性及稳定性明显优于Cu_2O/Ti电极。电位-0.5 V(相对于饱和甘汞电极)下脉冲沉积60mC制备的电极对CO_2还原具有较高的光电催化活性。在装有100 m L 0.1 mol/L NaHCO_3溶液的自制密闭反应器中利用Cu_2O/TNTs电极光电催化还原CO_2,合成的产物主要为甲醇,还原5 h后甲醇含量达到6.05 mg/L。

TiO2 nanotubes （TNTs） arrays obtained by anodization of titanium were used as a matrix to prepare a Cu20/ZNTs electrode via pulse electrodeposition of CUE0 on the walls of TNTs. The morphology of the electrode and the valence of deposit on it were characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and X-ray photoelectron spectroscopy （XPS）. The effects of deposition potential and charge on photoelectrocatalytic properties of the as-prepared electrode were studied by cyclic voltammetry and photocurrent-time curve measurement. It was shown that the deposits are Cu20 nanoparticles. The photoelectroactivity and stability of CUEO/TNTs electrode are better than that of a CuEO/Ti electrode. The Cu20/TNTs electrode prepared at a deposition potential of-0.5 V （vs. saturated calomel electrode） with a deposition charge of 60 mC presents high photoelectroactivity for COz reduction. The photoelectrosynthesis performed in a homemade airtight reactor with 100 mL of 0.1 mol/L NaHCO3 solution using the CuzO/TNTs electrode proved that the main reduction product is methanol with a yield reaching 6.05 mg/L after reduction reaction for 5 hours.