Fabrication of a Novel SnO2 Photonic Crystal Sensitized by CdS Quantum Dots and Its Enhanced Photocatalysis under Visible Light Irradiation

SnO2 photonic crystal (SnO2 PC) sensitized with CdS quantum dots (SnO2 PC/CdS QDs) was structured on FTO substrate to enhance photocatalysis. Scanning electron microscopy indicated that the CdS QDs with an average of 5 nm to 10 nm were dispersed uniformly into the SnO2 PC. The results of the transmittance spectra indicated that the light absorption was redshifted to 500 nm, and that the optical absorption for SnO2 PC/CdS QDs was sharply more than for the SnO2 film in the 400 nm to 600 nm ranges. Meanwhile, good match between the peak position of photonic band gap (PBG) and the absorption of CdS enhanced the photoconversion efficiency up to 16.8 times and improved the photocurrent up to 9 times than that of SnO2 film. The Bode phase plot of the samples were also conducted to further demonstrates the lower recombination of the photogenerated carriers. After 3 hours’ treatment, the removal rate of carbamazepine (CBZ) on SnO2 PC/CdS QDs was 98.8%, and the rate constant (k) on SnO2 PC/CdS QDs was 12.5 times than that on the SnO2 film/CdS QDs.

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