Carbon quantum dots decorated CuS nanocomposite for effective degradation of methylene blue and antibacterial performance

Abstract The development of conventional semiconductor photocatalyst is hampered by narrow wavelength response and high recombination rate between the photo-generated electron and hole pairs. Semiconductor composite technology is an effective method to enhance the efficiency of photocatalytic degradation by separating the photon-generated carrier or changing the band gap of semiconductors effectively. Here, we report a simple hydrothermal treatment to synthesize carbon quantum dots@cupric sulphide (CQDs@CuS) nanocomposite. The nanocomposite displayed a high efficiency to degrade methylene blue (MB) under visible light and antibacterial property to Bacillus subtilis (B. subtilis). The findings could be explained that CQDs as electron donators could interact with CuS which resulted in the change of band-gap energy of CQDs@CuS nanocomposites. The lower band-gap energy increased their efficiency to photocatalytic degradation of organic dyes under visible light.