Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (12): 2427-2432.doi: 10.3866/PKU.WHXB20091210

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Enhanced Photoelectrochemical Performance of WO3 Film Electrode under Visible Light by Electrochemical Etching Fluorination in Aqueous Solutions Containing Fluorine

LI Wen, LENG Wen-Hua, NIU Zhen-Jiang, LI Xiang, FEI Hui, ZHANG Jian-Qing, CAO Chu-Nan   

  1. Department of Chemistry, Yuquan Campus, Zhejiang University, Hangzhou 310027, P. R. China; Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, Zhejiang Province, P. R. China; State Key Laboratory for Corrosion and Protection of Metals, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, P. R. China
  • Received:2009-05-17 Revised:2009-08-23 Published:2009-11-27
  • Contact: LENG Wen-Hua E-mail:lengwh@zju.edu.cn

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Abstract:

A new and simple method of electrochemical etching in acidic aqueous solutions containing fluorine for the electrodeposited WO3 thin films is presented. The samples were characterized by photoelectrochemistry, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy, and photoluminescence (PL). Results showed that the etching increased the specific surface area with a concomitant reduction in the catalyst mass and also a change in the surface status of the electrodes. This modification of the surface status improved the photoelectrochemical performance of the electrodes under visible and UV-Vis light illumination with the same mass and specific surface area. This enhancement can be ascribed to the surface fluorination of the electrodes, which result in a decrease in the surface recombination centers and a negative shift in the flatband potential. The light absorption and crystalline were found to be unchanged by etching. The etched WO3 film electrode shows excellent photoelectrochemical stability in acid solutions. This provides a novel method for increasing the photon electric conversion efficiency of WO3 thin filmelectrodes.

Key words: WO3, Electrochemical etching, Fluorination, Photoelectrochemistry, Visible light