Synthesis of Shape-Tailored WO3 Micro-/Nanocrystals and the Photocatalytic Activity of WO3/TiO2 Composites

Abstract

A traditional semiconductor (WO3) was synthesized from different precursors via hydrothermal crystallization targeting the achievement of three different crystal shapes (nanoplates, nanorods and nanostars). The obtained WO3 microcrystals were analyzed by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectroscopy (DRS). These methods contributed to the detailed analysis of the crystal morphology and structural features. The synthesized bare WO3 photocatalysts were totally inactive, while the P25/WO3 composites were efficient under UV light radiation. Furthermore, the maximum achieved activity was even higher than the bare P25’s photocatalytic performance. A correlation was established between the shape of the WO3 crystallites and the observed photocatalytic activity registered during the degradation of different substrates by using P25/WO3 composites.

Polyoxometalates: Tailoring metal oxides in molecular dimension toward energy applications

“…The nanoparticles of WO 3 are more active than the bulk form, exhibiting good optoelectronic performance in various arrangements. For example, WO 3 nanoparticles exhibit comparable photocatalytic properties for organic degradation compared with the TiO 2 counterpart P25, 172,173 and photovoltaic effects are generated when they are incorporated in dye-sensitized solar cells, achieving a 1.46% power conversion efficiency when treated with TiCl 4 . 174 Polyoxotungstates have been extensively researched for dye-sensitized solar cells subjected to the metal and ligand modification.…”

A review on copper vanadate‐based nanostructures for photocatalysis energy production

“…In the same year, Willoughby Smith gave his concept of photoconductivity. By the help of the concept of photoconductivity, Charles Fritts constructed a solar cell in1883 . Edwin Herbert Hall gave his concept of Hall effect in 1878, according to which solids contain charge carriers which are deflected by the applied magnetic field.…”

“…By the help of the concept of photoconductivity, Charles Fritts constructed a solar cell in1883. 77 Edwin Herbert Hall gave his concept of Hall effect in 1878, according to which solids contain charge carriers which are deflected by the applied magnetic field. Later on in 1899, Eduard Riecke gave his theory about the charge carriers present in the conducting materials; according to this theory, every conducting material contains different amounts of negative and positive charge carriers having different velocities in different directions.…”

Detailed Spectroscopic and Structural Analysis of TiO2/WO3 Composite Semiconductors

“…In the case of WO 3 , only the monoclinic crystalline phase was detected, as it can be seen from the diffractogram. However, based on our previous work [33], one can infer that this synthesis procedure gives rise to hierarchical structures made up from fine micrometric needle crystals (30-50 nm wide and 3-4 µm long) that form a star-like shaped structure (therefore the Scherrer equation was not used). e particle size of the WO 3 stars was between 3 and 4 µm (as described in Section 3.3).…”

“…e most commonly used methods for the preparation of WO 3 /P25 composites are the mechanical mixing or the adjustment of the semiconductors' surface charge, and in both cases, the composites photocatalytic efficiency was improved as compared to that exhibited by P25 [32,33].…”