偏压控制Cu_2O和Cu在TiO_2表面的生长及其光电化学性质(英文)  

Bias-Determined Cu_2O and Cu Growth on TiO_2 Surface and Their Photoelectrochemical Properties

作　　者：姜春香[1] 胡玉祥[1] 董雯[1] 郑分刚[1] 苏晓东[1] 方亮[1] 沈明荣[1] 

机构地区：[1]苏州大学物理与光电能源学部,江苏省重点薄膜实验室,江苏苏州215006

出　　处：《物理化学学报》2014年第10期1867-1875,共9页Acta Physico-Chimica Sinica

基　　金：supported by the National Natural Science Foundation of China(91233109,51272166,11004146);Natural Science Foundation of Jiangsu Province,China(BK2012622);Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China~~

摘　　要：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 （CV） of TiO2/Ti electrodes in Cu^2＋ ion solution, we fabricated Cu2O and Cu particles onto TiO2 flat surfaces separately or simultaneously by adjusting the applied potentials during electrodeposition. Scanning electron microscopy （SEM）, X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS） showed that Cu2O and Cu have different growth modes： Cu2O particles crystallize on the TiO2 surface separately while Cu particles nucleate on previously grown particles, forming a stacked particle structure. This growth behavior can be explained by the different electron transfer behavior on the Cu2O/TiO2 and Cu/TiO2 interfaces and this is determined by their bandgap alignments. Compared with a pure TiO2 photoanode, a significant enhancement of the photocurrent was observed for both the Cu2O/TiO2 and Cu/TiO2 heterostructures. A potential region exists where Cu2O and Cu grow on the TiO2 surface simultaneously and the corresponding photocurrent is relatively stable and reaches a maximum. UV-Vis diffuse reflectance spectroscopy, electrochemical impedance spectroscopy （EIS）, and photocurrent vs potential characteristics revealed that the visible light absorption by Cu20 and Cu contributes significantly to the photocurrent. Cu/TiO2 resulted in greater broadband visible light utilization during the photoelectric conversion. Additionally, the increased zero-current potential and the effective charge separation as well as the rapid carrier transfer on the electrode/electrolyte interface are also related to the enhanced photoelectrochemical properties.

关 键 词：氧化亚铜 铜 电化学沉积 光电化学性质 二氧化钛薄膜 

分 类 号：O646.54[理学—物理化学] O614.411[理学—化学]