Photoelectrocatalytic activity of bi-layer TiO2/WO3 coatings for the degradation of 4-chlorophenol: effect of morphology and catalyst loading

Abstract

WO 3 and bi-layer WO 3 /TiO 2 coatings of different catalyst loadings were electrosynthesized on stainless steel 304 (SS) substrates from acidic aqueous solutions by single-step and consecutive steps potentiostatic cathodic deposition. The resulting WO 3 /SS and TiO 2 /WO 3 /SS photoelectrodes were screened for their photoresponse under ultraviolet (UV) and visible light illumination by photovoltammetry and photoamperometry in sulphate solutions, in the absence and presence of 4-chlorophenol (4-CP). They were also evaluated for bulk photo-oxidation of 4-CP under constant potential, in the voltage range determined on the basis of the photovoltammetric tests. The optimal weight ratio between TiO 2 and WO 3 was also established, ensuring the best performance of these photoelectrodes for the photooxidation of 4-CP under UV and visible light irradiation.

Achievements and Trends in Photoelectrocatalysis: from Environmental to Energy Applications

“…The use of bicomponent nanostructured TiO 2 /WO 3 electrode prepared by the template method promoted 97 % of decolorization of the indigo carmine dye and 62 % of mineralization under applied potential of 1.0 V under visible light irradiation [105]. The literature reports some works involving photoelectrocatalytic oxidation of organic compounds using bicomposites of TiO 2 /WO 3 [106][107][108][109][110].…”

The Relationship between the Mesostructure of WO3/TiO2 Hollow Microsphere and its Property

“…[1][2][3][4][5][6][7][8] Recently, the improvement of the photocatalytic property of a tungsten trioxide/titanium dioxide composite was attributed to the similarity of the band structures of tungsten trioxide and titanium dioxide, 6,9 the separation of photogenerated electron-hole pair in the composite [1][2][3]6,[8][9][10][11][12][13][14][15][16][17][18][19] and the enhanced acidity on its surface. 7,14,20,21 Furthermore, the presence of heterojunctions 1,4,15,[22][23][24] and doping 8,10,12,25,26 in the composite facilitates the separation of photoinduced electron-hole pairs. The presence of lattice distortion 8,10,12,26,27 in the composite not only facilitates the generation of photoinduced electron-hole pairs, but also postpones their recombination.…”

Photocatalytic activity of needle-like TiO2/WO3−x thin films prepared by chemical vapour deposition

“…At the same time, an effective adsorption and high-surface area are crucial for the efficiency of semiconductor photocatalysts, which has encouraged the application of surface modification processes and the development of morphology-controlled synthesis methods [5]. Ideally, these methods should ensure an open or porous morphology, together with a homogeneous mixture of the two oxide semiconductors [6]. For instance, mesoporous WO 3 /TiO 2 films have successfully shown an enhanced activity in the degradation of organic pollutants [7,8].…”