Preparation of VO2 (M) nanoparticles with exemplary optical performance from VO2 (B) nanobelts by Ball Milling

• Published in: Journal of alloys and compounds 2021-10, Vol.877, p.159888, Article 159888
• Main Authors: Wang, Cheng, Xu, Huiyan, Wang, Chiyuan, Liu, Tongyao, Yang, Shuaijun, Nie, Yong, Guo, Xiaodan, Ma, Xin, Jiang, Xuchuan
• Format: Article
• Language: English
• Subjects: Annealing; Ball milling; High temperature; Light transmittance; Morphology; Nanoparticles; Optical properties; Phase transformation; Phase transitions; Process parameters; Room temperature; Smart materials; Smart windows; Vanadium dioxide; Vanadium oxides; Windows (apertures)
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.159888

Vanadium oxide (B) (VO2 (B)), easily obtained by a hydrothermal method, can be transformed to VO2 (M/R) under high-temperature annealing treatment (> 500 °C) without oxygen atmosphere. However, the coarsening of VO2 (M/R) particles is always observed after high-temperature annealing, which may seriously degrade optical properties. In this study, the ball milling method is used, for the first time, to transform VO2 (B) nanobelts into spherical VO2 (M/R) nanoparticles with the average particle size of 38 nm at room temperature and under atmospheric conditions. The effects of ball-to-powder weight ratio (BPR) and milling time on crystalline phase and morphology of VO2 were systematically investigated and found the optimum processing parameters with BPR of 10:1 and the milling time of 3 h. The thin coating based on the obtained VO2 (M/R) nanoparticles shows good optical properties that the modulation ability can reach up to 14.03% while the visible light transmittance is 41%, which promotes the practical application in smart windows. In addition, the mechanism of the phase transformation from VO2 (B) to VO2 (M/R) is analyzed and confirms that the pressure caused by ball collision plays a major role in the ball milling process. [Display omitted] •VO2 (B) was transformed into VO2 (M) by high-energy ball milling at room temperature and atmospheric conditions.•The optical properties of the milled samples are obviously better than those of the annealed samples.•The high-energy ball milling method is a new idea for the preparation of VO2 (M).•The pressure produced by ball impact is the driving force of phase transformation.•The high-energy ball milling method provided a new method for solid phase preparation of VO2 (A).