SnO2/graphene quantum dots composited photocatalyst for efficient nitric oxide oxidation under visible light

In the present work, we have prepared tin oxide (SnO2)/graphene quantum dots (GQDs) composites and applied them for photocatalytic removal of nitric oxide (NO). In contrast to SnO2 alone, SnO2/GQDs composite has exhibited a remarkably enhanced activity under both full spectrum and visible light illumination. The crystal structure, morphology and surface state of the composite were studied by X-ray diffraction, transmission electron microscopy, Fourier-transformed infrared spectroscopy and X-ray photoelectron spectroscopy. Moreover, diffraction and reflectance spectra and photoluminescence spectra together with the photoelectrochemical tests show that the presence of GQDs in the composite could promote the visible light response as well as charge separation efficiency of the system. This makes SnO2/GQDs composite generate more active species (O2− and OH) for NO oxidation, as evidenced from the electron paramagnetic resonance measurements. This study hence could be referenced for future construction of efficient photocatalytic systems with wide bandgap oxides.