Photocatalytic activity of TiO2/SnO2 nanostructures with controlled dimensionality/complexity

• DOI: 10.1016/j.apsusc.2018.11.226
• Publication Date: 2018-11-29T04:55:57Z
• Authors: A. Kusior; L. Zych; K. Zakrzewska; M. Radecka
• Keywords: Photodegradation; Rutile

Abstract Different chemical routes such as Flame Spray Synthesis (FSS), sol-gel technique (S-G), hydrothermal reactions (HR) and mechanical mixing (MM) have been adopted to prepare: 0D-0D, 0D-3D and 3D-0D TiO2/SnO2 nanostructures for photocatalytic applications. Characterization of the nanostructures has been performed using the following methods: X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, Brunauer-Emmett-Teller (BET), zeta-potential, and uv/vis spectrophotometry. Photocatalytic activity of the nanostructures has been determined from the kinetics of methylene blue (MB) photodegradation under uv radiation. Correlation between the dimensionality/complexity of the nanostructures and their photocatalytic performance has been analysed. The highest pseudo-primary rate constant kapp of about 0.12–0.13 min−1 has been demonstrated for MB decomposition by core-shell TiO2/SnO2 0D-3D nanopowders. Theoretical explanation of this effect involves calculations of separation between conduction (valence) band edges ΔCB (ΔVB) for anatase (A-TiO2)/rutile(R-TiO2)/cassiterite(SnO2) heterojunction. The highest ΔCBA_R = 0.12 eV and ΔCBR_SnO2 = 0.22 eV in the case of 0D-3D core-shell nanostructures result in accumulation of electrons at SnO2 while holes are transferred to TiO2 (rutile or anatase).