Influence of surfactants on the morphology of SnO2 nanocrystals prepared via a hydrothermal method

Nanoscaled SnO2 with different morphologies has been synthesized via a simple hydrothermal process at 180 °C using polyvinylpyrrolidone (PVP), sodium dodecyl sulfonate (SDS), cetyl trimethyl ammonium bromide (CTAB) or tetrapropyl ammonium bromide (TPAB) as surfactant. All the prepared SnO2 are of a tetragonal crystal structure. Nanocubes, nanorods, nanosheets, nanobelts and nanoparticles were prepared when changing the type and dosage of organic surfactants. It is shown that anionic surfactant (SDS) and cationic surfactant (CTAB or TPAB) at their suitable addition amounts can largely influence the morphologies of SnO2 nanocrystals. The effect is significantly dependent on the solvent types: water or ethanol. The non-ionic surfactant (PVP) can also change the morphologies like SDS but the impacts are less obvious. The effect of surfactants on the shape and size of SnO2 nanoparticles was discussed in detail. The particle growth mechanism is described based on the electrostatic interactions and Van der Waals’ forces.