Synthesis and applications of WO₃ nanosheets: the importance of phase, stoichiometry, and aspect ratio

Abstract

WO3 is an abundant, versatile oxide that is widely explored in catalysts, sensors, electrochromic devices, and numerous other applications. The exploitation of WO3 in nanosheet form provides potential advantages in...

A review: research progress on the formation mechanism of porous anodic oxides

“…The research focus on PAO initially focused on PAA and ATNTs, and with the development of preparation technology, the research interest in the anodization of other valve metal oxides is also rising, such as Zr, Sn, Ni, Ta, V, Nb, W and Cu. 23,28,54,69,88,[109][110][111][112][113] These metals can be prepared by anodization to form films with regular nanotube arrays which have shown wide application potential in a wide variety fields such as sensors, supercapacitors, and photocatalysis. 111,[114][115][116][117][118][119][120][121][122][123][124][125][126] Because of its simple and efficient preparation process and low cost, it also has a good prospect in future industrial production.…”

“…23,28,54,69,88,[109][110][111][112][113] These metals can be prepared by anodization to form films with regular nanotube arrays which have shown wide application potential in a wide variety fields such as sensors, supercapacitors, and photocatalysis. 111,[114][115][116][117][118][119][120][121][122][123][124][125][126] Because of its simple and efficient preparation process and low cost, it also has a good prospect in future industrial production. Therefore, further research on the mechanism is of great significance to the preparation of nanoporous materials with precise structures.…”

Position-Selective Growth of WO3 Nanosheets for NH3 Gas Sensors

“…WO 3 , which is an n-type semiconductor, is one of the widely studied metal oxides owing to its fascinating properties resulting from its structural transformations and substoichiometric phases. − These arise mainly from the tilting of the WO octahedra and the displacement of the W atom . The order of phase transition has been established as follows: monoclinic (εWO 3 ) < −43 °C, triclinic (δWO 3 ) −43 to 17 °C, monoclinic (γWO 3 ) 17 to 330 °C, orthorhombic (βWO 3 ) 330 to 740 °C, and tetragonal (αWO 3 ) > 740 °C. , …”

“…The synthesis route of WO 3 plays a crucial role in determining the resulting physiochemical properties. − In general, the commonly followed synthesis routes fall into the solid-, liquid-, and vapor-phase categories. ,, In terms of simplicity, the liquid-phase synthesis is preferred over vapor- and solid-phase syntheses; however, it uses environmentally unfriendly solutions. The vapor- and solid-phase syntheses allow good control of the resulting structure and produce neat specimens; however, they involve high-temperature processes.…”

Kinetic Studies of WO3-Based Photochromism in Polyvinyl Alcohol Film

“…Tungsten oxide (WO 3 ) has attracted much attention due to its reversible color change between colorless or white and blue. − Partial reduction of W 6+ to W 5+ and insertion of proton for a charge compensation in WO 3 generate a tungsten bronze (H x WO 3 ), which exhibits blue coloration by the intervalence charge transfer (IVCT) transition of electrons between the neighboring W 5+ and W 6+ . The blue coloration occurred due to electrochemical reduction or by band-gap excitation under UV irradiation is referred to as electrochromism or photochromism, respectively.…”