Photocatalytic properties of nanocrystalline TiO2 modified with CuO and WO3

Abstract

Much attention is paid to studies of the processes occurring in heterogeneous catalysis with the use of nanomaterials, in particular, photocatalysis. Titanium dioxide and zinc oxide are among the most widespread photocatalysts due to their high chemical stability, suitable band gap, and rather high lifetime of nonequilibrium electron-hole pairs. In order to increase the photocatalytic activity (PCA) of these materials, including the case of a visible light action, various approaches are applied, in particular, the development of a composition material with a metal-semiconductor or semiconductor-semiconductor contact. We have chosen semiconductors of n-type (WO 3 ) and p-type (CuO) as components of such composites because of their potential positive influence on the PCA of titanium dioxide at the expense of spatial separation of nonequilibrium charge carriers and, respectively, increase in their lifetime. In order for the obtained composites to be commercially valuable, we have chosen a method of synthesis by modifying the ready TiO 2 preparations, including those that are commercially available (Degussa P25). It has been shown that the modification with CuO lowers PCA of titanium dioxide, while the modification with WO 3 enhances it by 25%. It has been demonstrated that WO 3 /TiO 2 composite manifests PCA under visible light illumination.

The microstructure effect on the Au/TiO2 and Ag/TiO2 nanocomposites photocatalytic activity

“…Loading of the titania surface with semiconductor NPs results in a visible-light induced PCA and increases the total (UV and visible) PCA in the case of II-type heterojunction formation. As demonstrated in our earlier article [15], the PCA of nanocomposite based on Aeroxide P25 and WO 3 •H 2 O was increased by ca. 30% higher in comparison with the pristine Aeroxide P25.…”

“…During the experiment, the reaction mixture was pumped through Malvern Instruments DTS1070 cell, where the absorption spectra was acquired every 3 s using the xenon HRX-2000 lamp and Ocean Optics QE65000 spectrometer. The details of experimental setup and data processing are described in our previous articles [15,57]. In the work [57], we demonstrated, that in the case of this set up the obtained data of the MO decoloration corresponds to the oxidative photodegradation of MO.…”

Photochromic and Photocatalytic Properties of Ultra-Small PVP-Stabilized WO3 Nanoparticles

“…Photochromic and photocatalytic experiments were carried out in the flow-type measuring system. WO 3 @PVP sols were irradiated using a high-pressure mercury lamp with a power of 5.5 W. The complete scheme of the setup is described elsewhere [36]. The suspension absorption spectra were measured using an HRX-2000 xenon lamp, an Ocean Optics QE65000 spectrophotometer, and Ocean Optics fiber optics.…”

Mesoporous Titanium Dioxide: Synthesis and Applications in Photocatalysis, Energy and Biology

“…Although mesoporous TiO 2 photocatalysts have been widely used, certain disadvantages, for example low photonutilization efficiency and poor absorption of visible light due to large band gap of TiO 2 (3–3.2 eV) have also limited their application. Therefore, a large amount of efforts has been directed to the modification of the material with the purpose of improving the photocatalytic effect and activity of mesoporous TiO 2 photocatalysts [ 48 , 49 , 50 , 51 , 52 ]. Among them, doping is one of the most promising ways for enhancing the performance of mesoporous TiO 2 .…”