Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (10): 1867-1875.doi: 10.3866/PKU.WHXB201407221

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

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.

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