论文部分内容阅读
基于TiO2/Ti电极在含Cu2+溶液中的循环伏安图,调节电沉积的沉积电压,我们在TiO2平整表面制备出Cu2O和/或Cu颗粒.通过扫描电镜(SEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)表征,发现Cu2O和Cu有不同的生长机制:Cu2O颗粒在TiO2表面分散结晶,而Cu颗粒是在已生长的颗粒上成核,从而形成堆积颗粒结构.这是由于在Cu2O/TiO2界面和Cu/TiO2界面形成不同的能带结构,使得电子的转移方式不同.与纯TiO2光阳极比较,可以观察到Cu2O/TiO2和Cu/TiO2异质结构的光电流均有显著增强.特别地,存在一个电压区间使得Cu2O和Cu同时生长在TiO2表面,此时对应的光电流比较稳定并且能达到最大.紫外-可见(UV-Vis)漫反射光谱、电化学阻抗谱(EIS)和光电流-电压特性曲线均显示,Cu2O和Cu明显有助于光的可见光吸收,同时Cu/TiO2在光电转换过程中显示更宽波段的可见光利用率.此外,开路电压的增加、有效的电荷分离和电极/电解质界面上载流子的快速迁移也增强了材料的光电化学性质.
Based on the cyclic voltammogram of TiO2 / Ti electrode in Cu2 + -containing solution, the deposition voltage of electrodeposition was adjusted, and Cu2O and / or Cu particles were prepared on the flat surface of TiO2.The structure of Cu2O and / or Cu particles were characterized by scanning electron microscope (SEM), X-ray diffraction And X-ray photoelectron spectroscopy (XPS), we found that Cu2O and Cu have different growth mechanisms: Cu2O particles disperse and crystallize on the surface of TiO2, and Cu particles nucleate on the grown particles to form a stacked particle structure. Due to the formation of different band structures at the Cu2O / TiO2 interface and Cu / TiO2 interface, the electron transfer modes are different.Compared with the pure TiO2 photoanode, the photocurrent of Cu2O / TiO2 and Cu / TiO2 heterostructures are both In particular, there is a voltage interval so that Cu2O and Cu are simultaneously grown on the surface of TiO2, at this time the corresponding photocurrent is relatively stable and can reach the maximum.UV-Vis diffuse reflectance spectroscopy, electrochemical impedance spectroscopy EIS) and photocurrent-voltage characteristic curves show that Cu2O and Cu contribute significantly to the visible light absorption of light, while Cu / TiO2 shows a wider band of visible light utilization during photoelectric conversion.In addition, the increase of open circuit voltage, effective Charge separation and The rapid transport of carriers at the electrode / electrolyte interface also enhances the photoelectrochemical properties of the material.