物理化学学报 >> 2014, Vol. 30 >> Issue (6): 1099-1106.doi: 10.3866/PKU.WHXB201404282

电化学和新能源 上一篇    下一篇

氢氟酸腐蚀对α-Fe2O3薄膜光解水电极光电化学性质的影响

胡玉祥, 姜春香, 方亮, 郑分刚, 董雯, 苏晓东, 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:2014-03-21 修回日期:2014-04-25 发布日期:2014-05-26
  • 通讯作者: 沈明荣 E-mail:mrshen@suda.edu.cn
  • 基金资助:

    国家自然科学基金(91233109)和江苏省高校优势学科项目资助

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.

摘要:

使用溶胶-凝胶法制备了α-Fe2O3薄膜,研究了氢氟酸腐蚀薄膜表面对其光电化学性质的影响. 实验发现,薄膜表面的孔洞和间隙随着氢氟酸浸蚀时间的增长而发生变化. 氢氟酸浸蚀5 min,α-Fe2O3电极的光电流降低;随后随浸蚀时间增加而迅速增加;当浸蚀时间大于15 min时,其光电流再次下降,但对浸蚀过的样品再次退火可以使光电流大幅增加. 通过电化学交流阻抗谱、拉曼和X射线光电子能谱分析,提出了两个影响光电流的因素:氢氟酸表面浸蚀造成薄膜表面的多孔性和结晶度降低. 为此,通过示意图解释了结合浸蚀和退火后处理两个步骤来增强α-Fe2O3薄膜光解水电极光电活性的原理. 相对于初始的α-Fe2O3电极,浸蚀并且再退火处理后,其光电性质更加稳定.

关键词: α-Fe2O3光电极, 表面处理, 光电化学性质

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