Continuous flow hydrothermal synthesis of rutile SnO2 nanoparticles: Exploration of pH and temperature effects

• Published in: The Journal of supercritical fluids 2020-12, Vol.166, p.105029, Article 105029
• Main Authors: Mamakhel, Aref, Søndergaard, Martin, Borup, Kasper, Brummerstedt Iversen, Bo
• Format: Article
• Language: English
• Subjects: Continuous flow hydrothermal synthesis; Nanoparticles; Tin (IV) oxide
• ISSN: 0896-8446; 1872-8162
• DOI: 10.1016/j.supflu.2020.105029

[Display omitted] •Phase pure rutile SnO2 NPs were synthesized by a continuous flow hydrothermal method.•SnO2 NPs prepared with considerable size and morphology control.•At low and high pH obtained nanorods under near critical or supercritical conditions.•SnO2 nanoparticles with 3.5 nm in size had BET of 185 m2. g-1 and a band gap of 4.0 eV.•The initial discharge capacity of SnO2 produced at 250 °C was 1378 mA h.g-1. SnO2 nanoparticles have been prepared by a continuous flow hydrothermal method using SnCl4∙5H2O and aqueous sodium hydroxide as precursor solutions. The syntheses were carried out in an experimental matrix of four different precursor pH values (1, 3, 7 and 11) and four different temperatures (250, 300, 350, 400 °C). Both temperature and pH affect the crystallite size and morphology providing considerable synthesis control over the nanoparticle characteristics. At intermediate pH (3 and 7) quite spherical nanoparticles are obtained and higher synthesis temperature results in larger nanoparticles (3–6 nm). A highly peculiar behavior is observed at either low pH (1) or high pH (11), where larger anisotropic nanorods (width 6−9 nm, length 20−40 nm) are obtained for the reaction near or in the supercritical regime (350 and 400 °C). Pore size and band gap were determined for all products, and selected samples were tested as anode materials in Li ion batteries.