还原氧化石墨烯复合方式对Ag-TiO2基光电极电子传输性能的影响

Effect of Reduced Graphene Oxide Composite Method on Electron Transport Performance of Ag-TiO2 Based Photoelectrodes

为进一步提高Ag-TiO2光催化效能,制备了还原氧化石墨烯(rGO)复合Ag-TiO2基的光电极。先通过对比不同的复合方式探究rGO对Ag-TiO2光催化剂表面电子传输和四环素降解效能的影响;再通过电化学阻抗谱测量、莫特-肖特基曲线等电化学手段对电极进行表征。结果表明:分层复合方式主要降低载体表面控制电极双层/薄膜的界面电阻,而全混复合方式主要降低总电荷转移电阻;分层电极的电子供体浓度随rGO质量分数增加而增大;在rGO质量分数为0.45%和0.25%时,分层复合和全混复合材料对四环素的降解速率分别比Ag-TiO2提高11.4%和2.3%;在外加0.5 V偏压下,分层复合电极LG6降解效率比未加外偏压时提高了5.3%,而全混复合电极MG2效率没有提升。分层复合方式能更有效地提高光催化剂表面电子传输效能。

The reduced graphene oxide(rGO)doped and Ag-TiO2 based photoelectrodes were prepared to study the effect of the composite method on the electron transport and tetracycline degradation by photocatalyst.The electrodes were characterized by electrochemical impedance spectroscopy and Mott-Schottky curve.The results showed that the interface resistance of the double-layer/thin film was reduced by the layered composite method on the surface of the carrier;while the total charge transfer resistance was mainly reduced by the fully mixed composite method.In addition,the concentration of the electron donor increased with the increasing of composite amount.When the rGO mass fraction was 0.45%and 0.25%,the degradation rate of tetracycline by the layered composite and the fully mixed doped electrode was 11.4%and 2.3%higher than that of Ag-TiO2,respectively.Under the applied 0.5 V bias voltage,the LG6 degradation efficiency of the layered composite electrode was increased by 5.3%;while the MG2 efficiency of the fully mixed composite electrode was not improved.The layered composite method can improve the electron transport efficiency more effectively on the surface of photocatalyst.