Morphology, Structure and Photoelectrocatalytic Activity of TiO[sub 2]/WO[sub 3] Coatings Obtained by Pulsed Electrodeposition onto Stainless Steel

Abstract

By applying pulsed electrodeposition instead of continuous electrodeposition for the consecutive preparation of each layer, a favorable modification is targeted of photoelectrocatalytic activity of the TiO2/WO3TiO2/WO3 couple. The morphology, structure, and related composition distribution of the films onto stainless steel substrates are characterized by scanning electron microscopy–energy-dispersive spectroscopy and Raman spectroscopy. The photocurrents at photoelectrodes with various loading, structure, and morphology are evaluated in the presence and absence of the model pollutants Na-oxalate and 4-chlorophenol (4-CP) under UV and visible light illumination. The effectiveness for bulk photodecomposition of 4-CP is estimated by long-term photoelectrolysis at constant potential using spectrophotometry. An increase (relative to single WO3WO3 ) in the photoelectrocatalytic activity of TiO2/WO3TiO2/WO3 under visible light is noticed and discussed. Clear indications are observed for the need to optimize the TiO2/WO3TiO2/WO3 loading, surface morphology, structure, and composition distribution to design high performance photocatalysts.