Enhanced photocatalytic capability of SiO2/CQD nanocomposites

It is also well known that naked SiO2 is not an efficient photocatalyst due to its relatively large band gap, which could only absorb short-wave ultraviolet light. In this report, SiO2/carbon quantum dot (SiO2/CQD, about 4 nm) nanocomposites were successfully prepared by one-step thermal method using tetraethylorthosilicate (TEOS) as the source of both silicon and carbon. The nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). These nanocomposites exhibit higher photocatalytic activity for rhodamine B (RhB) degradation than C-doped SiO2 and pure SiO2 nanoparticles under near-UV light irradiation at room temperature in air. In the present catalyst system, CQD play two important roles for the enhanced photocatalytic activity of SiO2/CQD nanocomposites. It is expected that these novel, environmentally friendly and highly photoactive SiO2/CQD nanocomposites may promote practical applications of photocatalysts and provide an effective approach to high-efficiency complex catalyst design.