Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (04): 865-870.doi: 10.3866/PKU.WHXB201202152

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Effects of Calcination Temperature on Morphologies and Photoelectrochemical Properties of Anodized WO3 Nanoporous Films

HUANG Ye, LIU Yu-Yang, LI Wen-Zhang, CHEN Qi-Yuan   

  1. Key Laboratory of Resources Chemistry of Nonferrous Metals Ministry of Education, School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China
  • Received:2011-12-02 Revised:2012-02-01 Published:2012-03-21
  • Contact: CHEN Qi-Yuan;
  • Supported by:

    The project was supported by the National High Technology Research and Development Program of China (863) (2011AA050528) and National Natural Science Foundation of China (51072232, 21171175).

Abstract: Visible-light-responsive WO3 porous films were synthesized via step-voltage anodization in NH4F/(NH4)2SO4 solution and calcined at various temperatures. The crystalline phase and surface morphology were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The as-anodized nanoporous films converted to a monoclinic phase with preferential orientation in the (020) planes, and the pore diameters of the films calcined below 450 °C were estimated to be in the region of 50-100 nm. The photocatalytic activity was evaluated via photodegradation of methyl orange. The film calcined at 450 °C showed the highest photocatalytic activity. Photoelectrochemical measurements showed that the incident photon-to-current conversion efficiency (IPCE) values of the film calcined at 450 ° C were 87.4% at 340 nm and 22.1% at 400 nm. Under visible light (λ ≥400 nm), the photocurrent density in 0.5 mol·L-1 H2SO4 solution at 1.2 V (vs Ag/AgCl (KCl saturated)) was 5.11 mA·cm-2. Electrochemical impedance spectroscopy (EIS) measurements showed that the film calcined at 450 °C exhibited the smallest interface charge transfer resistance and optimal electroconductivity. Perfect crystallinity, high porosity and low resistance can therefore be obtained by controlling the calcination temperature. A large surface area and a porous structure are important factors in affecting photocatalytic activity.

Key words: Tungsten oxide porous film, Photoelectrochemical property, Photodegradation, Incident photon-to-current conversion efficiency


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