电化学阻抗谱法研究铈改性TiO2纳米管阵列光电极裂解水产氢动力学

通过阳极氧化法在纯钛板上制备TiO2纳米管阵列电极.在光电化学电解池阳极中加入供电子物质乙二醇,显著减小了TiO2纳米管的电荷传递阻抗,促进了光电催化裂解水产氢反应.采用阴极电沉积和阳极氧化法制备了单质铈和氧化铈共同改性的TiO2纳米管阵列半导体光阳极,其平带电位向电负方向移动.采用电化学阻抗谱法(EIS)对改性后TiO2纳米管阵列在光电催化裂解水产氢中的电子传输性能以及界面性质进行了表征,确定了各阻抗弧对应的电极过程.采用合理的等效电路模型计算了电极的电子传输动力学参数.结果表明,经铈改性后的TiO2纳米管阵列膜电阻明显减小,有利于氢气的产生.探讨了单质铈与氧化铈促进TiO2纳米管阵列电荷传输的作用机理.

Dynamics Study on the Cerium and Oxidative Cerium Modified TiO2 Nanotube Arrays for Hydrogen Production by Water Splitting Using Electrochemical Impedance Spectrum

TiO2 nanotube arrays photoelectrodes were prepared by anode oxidation on pure Ti sheet.The donor material glycol(C2H6O2) added in the anode electrolyte significantly reduced the charge transfer impedance of TiO2 nanotubes to promote the photocatalytic water splitting for hydrogen production.TiO2 nanotube arrays electrodes were modified by cerium and oxidative cerium with electrochemical deposition and anodic oxidation.The flat band potential moves to the negative potential direction after modification.Electrochemical impedance spectrum(EIS) measurement was used to investigate the electron transfer characteristic in photoelectrodes and the interface characteristic in the photoelectrochemical cell(PEC) for hydrogen production.Arcs of EIS and corresponding electrode processes were discussed.Dynamic parameters of the electrodes were calculated by reasonable electrical equivalent circuit fitting.The results indicate that TiO2nanotube arrays electrode modified by cerium and oxidative cerium could largely decrease the electron transfer resistance which contributes to hydrogen production.The mechanism of the cerium and oxidative cerium acting on TiO2 nanotube arrays to promote charge transfer is discussed.