物理化学学报 >> 2014, Vol. 30 >> Issue (10): 1867-1875.doi: 10.3866/PKU.WHXB201407221

电化学和新能源 上一篇    下一篇

偏压控制Cu2O和Cu在TiO2表面的生长及其光电化学性质

姜春香, 胡玉祥, 董雯, 郑分刚, 苏晓东, 方亮, 沈明荣   

  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
  • 收稿日期:2014-04-30 修回日期:2014-07-21 发布日期:2014-09-30
  • 通讯作者: 董雯, 沈明荣 E-mail:dongwen@suda.edu.cn;mrshen@suda.edu.cn
  • 基金资助:

    国家自然科学基金(91233109,51272166,11004146),江苏省国家自然科学基金(BK2012622)及江苏省高等教育机构优势学科项目资助

Bias-Determined Cu2O and Cu Growth on TiO2 Surface and Their Photoelectrochemical Properties

JIANG Chun-Xiang, HU Yu-Xiang, DONG Wen, ZHENG Fen-Gang, SU Xiao-Dong, FANG Liang, SHEN Ming-Rong   

  1. Jiangsu Key Laboratory of Thin Films, College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, Jiangsu Province, P. R. China
  • Received:2014-04-30 Revised:2014-07-21 Published:2014-09-30
  • Contact: DONG Wen, SHEN Ming-Rong E-mail:dongwen@suda.edu.cn;mrshen@suda.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (91233109, 51272166, 11004146), Natural Science Foundation of Jiangsu Province, China (BK2012622), and 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.

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

Abstract:

Based on the cyclic voltammogram (CV) of TiO2/Ti electrodes in Cu2+ 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 Cu2O 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.

Key words: Cuprous oxide, Copper, Electrochemical deposition, Photoelectrochemical property, Titatium oxide film

MSC2000: 

  • O646