PEGME-bonded SnO2 quantum dots for excellent photocatalytic activity

Abstract

The ultrafine SnO₂ quantum dots (QDs) modified with poly(ethylene glycol methyl ether) (PEGME) (PEGME–SnO₂ QDs) were synthesized via hydrothermal method. X-ray diffraction and high-resolution transmission electron microscopy were employed to illustrate that the PEGME–SnO₂ QDs are uniform, monodispersed and about 4 nm in diameter. Then infrared spectrum and thermogravimetric analysis were used to prove that PEGME groups are bound tightly to SnO₂ surfaces. The as-synthesized PEGME–SnO₂ QDs excellently achieved photocatalytic degradation to Rhodamine B dye (RhB). The photon efficiency of the PEGME–SnO₂ QDs catalyst and corresponding RhB dye degradation rate constant could reach 0.0058% and 9.98 × 10⁻² min⁻¹, respectively. This outstanding photocatalytic performance could be attributed to not only large surface-to-volume ratio and high crystallinity of the ultrafine and monodispersed QDs, but also good hydrophilicity and conductivity of the PEGME surface modifier. Remarkably, such PEGME–SnO₂ QDs with outstanding photocatalytic efficiency and stable recyclability are promising to be applied to environmental purification.