Construction and photodegradation performance of CdS-Sn3O4 heterojunction

A uniformly distributed photocatalytic composite material CdS-Sn 3 O 4 heterojunction was constructed. Mixed valence tin oxide Sn 3 O 4 was selected as a co-catalyst to improve the stability and photocatalytic activity of the composite because Sn 3 O 4 possesses adjustable band gap and matches well with the CdS band position. The characterizations of EDS and XPS proved that Sn 3 O 4 was successfully loaded on CdS. The composite material exhibits an excellent band gap of 2.25 eV, a high photo-generated current intensity and good photoluminescence properties. Due to the timely transfer of photo-generated electrons from CdS material to Sn 3 O 4 , the recombination of electron and hole is reduced, resulting in significant increase of photocurrent density and photocatalytic efficiency. The photocatalytic degradation experiments show that CdS-Sn 3 O 4 possesses a significant degradation effect on antibiotics norfloxacin and tetracycline. Simultaneously, it also exhibits certain degradation effects on organic dye pollutants methylene blue and Rhodamine B. The active substances analysis shows that H 2 O 2 and hole (h + ) are the main active substances. Composite CdS-Sn 3 O 4 still maintains a stable structure and good photocatalytic activity after several photocatalysis cycles. In brief, this heterojunction material is promising in water treatment and environmental protection.