Effects of fluorine ions on the formation and photocatalytic activities of SnO2 nanoparticles with small sizes

Abstract

SnO₂ nanoparticles with small sizes were synthesized by a simple hydrothermal route with different dosages of fluorine ions. These nanoparticles all showed a typical rutile phase and excessive dosage of fluorine ions would result in other crystallographic phases. The average diameters of the as-prepared products were all smaller than 4 nm. The introduction of fluorine ions had little influence on the morphologies and crystallite sizes, but enhanced the crystallization of the rutile phase and promoted the growth of SnO₂ crystallites. XPS patterns showed that some introduced fluorine ions were physically adsorbed on the surface of SnO₂ crystals, but not doped in the lattice. The photocatalytic activities were tested by photodecomposition of Rhodamine B (RhB) under a 300 W high-pressure mercury lamp. The results indicated that a suitable amount of fluorine ions on the surface of SnO₂ nanoparticles caused significant enhancement of their photocatalytic activities.