Sol–gel preparation and characterization of SiO2 coated VO2 films with enhanced transmittance and high thermochromic performance

Vanadium dioxide (VO2) films prepared at low-temperature with a low cost are considerable for energy-saving applications. Here, SiO2 coated VO2 films with clearly enhanced visible transmittance by introducing antireflection coatings (ARCs) and excellent thermochromic performance were present. The VO2 films have been prepared via a stable and low-cost sol-gel synthesis route using vanadium pentaoxide powder as precursor, and their structural, morphological, optical and electrical properties and thermochromic performance were systemically characterized. The resistance of VO2 films varies by 4 orders of magnitude and the transmittance changes from 11.8% to 69.3% at 2500 nm while no significant deviation appears in the visible region during metal-insulator transition (MIT). Nanoporous SiO2 coating with good optical transparency was coated on the surface of VO2 film via sol-gel dip-coating technique to enhance its optical transmittance, and the visible transmittance is increased by 14.6% due to the significantly decreased reflectance. The critical transition temperature (63 degrees C) and infrared switching properties of VO2 films are not much deteriorated by applying SiO2 layer. The synergistic effect of antireflection and thermochromism on SiO2 coated VO2 films was investigated. (C) 2014 Elsevier B.V. All rights reserved.Chemistry, PhysicalMaterials Science, Coatings & FilmsPhysics, AppliedPhysics, Condensed MatterSCI(E)[email protected]; [email protected]

Non‐Aqueous Preparation of High‐Crystallinity Hierarchical TiO ₂ Hollow Spheres with Excellent Photocatalytic Efficiency

High-crystallinity hierarchical anatase TiO2 hollow spheres were prepared by a high-temperature (350 degrees C) and nonaqueous solvothermal method in the absence of water, templates, or additives. The hollow structures were assembled from highly crystallized TiO2 nanoparticles and exhibit superior photocatalytic properties relative to those of Degussa P25 TiO2 under irradiation with UV light. The influence of reaction temperature on the crystallinity, morphology, crystallite shape and size, band gap, specific surface area, and pore size distribution of TiO2 has been studied in detail. It is evident that reaction temperature is the most important factor to increase the crystallinity of TiO2 in order to improve its charge transfer and transport properties, which are important in photocatalysis.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000291561700011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, Inorganic & NuclearSCI(E)19ARTICLE182879-288

New facile synthesis of TiO2 hollow sphere with an opening hole and its enhanced rate performance in lithium-ion batteries

With the aid of the slow release of water from esterification reactions, a simple one-step solvothermal method was developed to prepare TiO2 hollow spheres with an opening hole. Organic carboxylic acids (CA) were exploited as not only the reactant to conduct esterification with ethanol, but also the coordination agent to modify titanium n-butoxide (TNB) to manipulate its hydroxylation and condensation process. The specific TiO2 morphologies prepared by this CA-assisted method significantly depend on the molecular structure and relative concentration of the carboxylic acids used. Appropriate carbon chain length of the CA molecule and the optimal molar ratio of CA/TNB are the essential factors to fabricate well-developed TiO2 hollow spheres with an opening hole. The surface hole facilitates active material transportation into the hollow interior, so this structure of TiO2 has been utilized in lithium-ion batteries and exhibits superiority in rate performance compared to closed spheres.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000314973000033&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, MultidisciplinarySCI(E)19ARTICLE3784-7893