Role of the growth step on the structural, optical and surface features of TiO2/SnO2 composites

• Main Authors: Luca Rimoldi, Daniela Meroni, Eleonora Pargoletti, Iolanda Biraghi, Giuseppe Cappelletti, Silvia Ardizzone
• Format: Article
• Language: English
• Published: The Royal Society 2019-01-01
• Series: Royal Society Open Science
• Subjects: titanium dioxide; tin oxide; tio2/sno2 composite; hydrothermal treatment; calcination
• Online Access: https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.181662

TiO2/SnO2 composites have attracted considerable attention for their application in photocatalysis, fuel cells and sensors. Structural, morphological, optical and surface features play a pivotal role in photoelectrochemical applications and are critically related to the synthetic route. Most of the reported synthetic procedures require high-temperature treatments in order to tailor the sample crystallinity, usually at the expense of surface hydroxylation and morphology. In this work, we investigate the role of a treatment in an autoclave at a low temperature (100°C) on the sample properties and photocatalytic performance. With respect to samples calcined at 400°C, the milder crystallization treatment promotes anatase phase, mesoporosity and water chemi/physisorption, while reducing the incorporation of heteroatoms within the TiO2 lattice. The role of Sn content was also investigated, showing a marked influence, especially on the structural properties. Notably, at a high content, Sn favours the formation of rutile TiO2 at very low reaction temperatures (100°C), thanks to the structural compatibility with cassiterite SnO2. Selected samples were tested towards the photocatalytic degradation of tetracycline in water under UV light. Overall, the low-temperature treatment enables to tune the TiO2 phase composition while maintaining its surface hydrophilicity and gives rise to well-dispersed SnO2 at the TiO2 surface.