The dependence of morphology, structure, and photocatalytic activity of SnO2/rGO nanocomposites on hydrothermal temperature

In this work, we determined the morphological, structural, and photocatalytic properties of SnO2/rGO nanocomposites dependent on hydrothermal synthesis temperature. SnO2/rGO nanocomposites were synthesized with a hydrothermal method from SnCl4.5H2O, NaOH, and graphene oxide (GO) precursors at temperatures ranging from 100 to 200 °C. X-ray diffraction (XRD) analysis showed that the average particle size of SnO2 nanocrystals increased with hydrothermal temperature, although the tetragonal rutile crystalline structure of SnO2 did not change as the hydrothermal temperature increased. SnO2 nanoparticles and reduced graphene oxide (rGO) sheets were observed in all SnO2/rGO samples obtained with different hydrothermal temperatures. Raman spectra indicated that GO was successfully reduced to rGO, and that SnO2 nanocrystals formed during the hydrothermal process. At an excitation wavelength of 270 nm, the photoluminescence emission band of SnO2 nanocrystals increased in intensity with increasing hydrothermal temperature, while the emission intensity of the SnO2 defects decreased. The photocatalytic properties of the nanocomposites were significantly improved when the hydrothermal temperature was raised from 100 to 180 °C.