Nanostructured Tungsten Oxide – Properties, Synthesis, and Applications

Abstract

This section focuses on the fundamental properties of nanostructured WO x and start with its various crystal structures and the conditions for phase transitions between these structures. The structures of nonstoichiometric WO x and WO 3 hydrates Nanostructured Tungsten Oxide -Properties, Synthesis, and Applications Metal oxides are the key ingredients for the development of many advanced functional materials and smart devices. Nanostructuring has emerged as one of the best tools to unlock their full potential. Tungsten oxides (WO x ) are unique materials that have been rigorously studied for their chromism, photocatalysis, and sensing capabilities. However, they exhibit further important properties and functionalities that have received relatively little attention in the past. This Feature Article presents a general review of nanostructured WO x , their properties, methods of synthesis, and a description of how they can be used in unique ways for different applications.

Investigating the Influence of Au Nanoparticles on Porous SiO2–WO3 and WO3 Methanol Transformation Catalysts

“…Dissociation of H 2 over Au NPs or reduced WO 3-x 30 and other electronic effects increased the reducibility of the surface oxygen of WO 3 , which led to oxygen vacancies at the catalyst surface. 27 This result was expected to have implications on the reactivity of the Au-loaded WO 3 catalysts in methanol transformation reactions.…”

“…Oxidations of olefins to epoxides are also readily accessible in the presence of WO 3 catalysts and peroxide, [23][24][25][26] and semiconducting WO 3 serves as a very efficient catalyst in photochemical and electrochemical oxidation reactions. [27][28][29] Despite success in these applications, catalysts containing mostly WO 3 have been limited in gasphase thermal oxidations of alcohols with O 2 or air as the only oxidant. The poor alcohol oxidation reactivity of pure WO 3 may be attributed to the non-labile lattice oxygen atoms of WO 3 under catalytic conditions that favor dehydration.…”

Orientationally textured thin films of WOxdeposited by pulsed laser deposition

“…The band gap in thin film WO 3 , however, is dependent on the grain structure; increasing the crystallite size decreases the band gap. Consequently adjusting the deposition parameters can tune absorption properties, and so thin film WO 3 is transparent to the majority of the visible light spectrum.…”

“…Pulsed laser deposition (PLD) is known to be an important method for the deposition of oxide materials [5], but there have been relatively fewer investigations of its utility in the deposition of WO 3 and substoichiometric WO x Following deposition using PLD from a WO 3 target using 308 nm radiation the microstructure and subsequent electrical properties of WO 3 thin films have been investigated [6,7], in particular the influence of substrate temperature and oxygen pressure. The films were deposited onto ITO coated glass and Si(111) substrates.…”

“…These properties have made thin film WO 3 the focus of various applications studies such as: thin film gas sensors [1], electro-chromic devices [2] and solar cell production [3,4].…”