Enhanced Photoelectrochemical Performance of WO3 Film Electrode under Visible Light by Electrochemical Etching Fluorination in Aqueous Solutions Containing Fluorine
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 thephoton electric conversion efficiency of WO3 thin film electrodes.
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