Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (6): 1099-1106.doi: 10.3866/PKU.WHXB201404282

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Effect of HF Treatment on the Photoelectrochemical Properties of a Hematite Thin Film Photoanode for Water Splitting

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

  1. Jiangsu Key Laboratory of Thin Films and College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, Jiangsu Province, P. R. China
  • Received:2014-03-21 Revised:2014-04-25 Published:2014-05-26
  • Contact: SHEN Ming-Rong E-mail:mrshen@suda.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (91233109) and Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, China.

Abstract:

The effects of HF treatment on the photoelectrochemical (PEC) properties of sol-gel prepared hematite (α-Fe2O3) thin films were investigated. Pores and interstices between the grains developed on the film surface as the HF etching time increased. The photocurrent density of the α-Fe2O3 photoanode decreased within the first 5 min of etching, and then increased quickly as the etching time increased. At longer time than 15 min the photocurrent density deteriorated. Re-annealing the etched samples significantly enhanced the photocurrent density. Based on electrochemical impedance spectroscopy, Raman and X-ray photoelectron spectroscopies, we propose that two factors contribute to photocurrent density reversely: the porosity and the lowered crystallinity of the α-Fe2O3 surface because of HF treatment.Aschematic model was compiled to explain the enhanced PEC activities of the etched plus re-annealed α-Fe2O3 photoanode. The PEC and water splitting measurements showed that the etched plus re-annealed photoanode is more stable than the as-prepared one.

Key words: α-Fe2O3 photoelectrode, Surface treatment, Photoelectrochemical property

MSC2000: 

  • O646