One-step ball milling synthesis of VO2 (M) nanoparticles with exemplary thermochromic performance

Vanadium dioxide (VO2) has demonstrated highly potential for smart windows because of its thermochromic property. This study represents the development of a facile but efficient method for the synthesis of VO2 (M) nanoparticles by ball milling method under ambient conditions, without release of waste liquid or gases. The key variables related to synthesis, including milling time and molar ratio of raw materials, have been investigated. It was found that the pure-phase VO2 (M) nanoparticles with the sizes of the particles ranged from 20 to 50 nm and relatively good dispersivity could be prepared by optimizing process parameters. For practice use to decrease the phase transition temperature, elemental W doping amount of 2 at.%, V1-xWxO2 (M) nanoparticles were also studied, and their glass coating exhibits high thermochromic performance with luminous transmittance (T-lum) of 44.18%, solar regulation efficiency (Delta T-sol) of 9.64%, and the critical phase transition temperature (T-c) of similar to 42 degrees C. This work demonstrates a green and promising ball milling method to fabricate large scale VO2 (M) and V1-xWxO2 (M) nanoparticles for smart windows.