Fabrication of Ag–Cu2O/PANI nanocomposites for visible-light photocatalysis triggering super antibacterial activity†
The Ag–Cu2O/PANI composite material was synthesized using a simple, fast, and low-cost process, which is attractive for its many applications in the fields of photocatalysis, surface enhanced Raman scattering (SERS), and characterization. SEM, TEM, XRD, FT-IR, TG, UV-Vis and XPS measurements confirmed the successful synthesis of the Ag–Cu2O/PANI composite material. First-principles calculations on the basis of density functional theory (DFT) were used to analyze regulation of the work function of Cu2O. The results showed that Ag–Cu2O/PANI had an extremely high stability when exposed to oxygen, water, and light for a long period of time, which was attributed to the physical coating of Ag nanoparticles (Ag NPs) transferring the electrons (e−) and holes (h+) inside the Cu2O to the surface through the Schottky barrier to prevent photocorrosion. The deposition of Ag NPs also increased the intensity and time of the oxidative stress reaction of Cu2O, as evidenced by the reactive oxygen species (ROS) test. Ag NPs distributed on the surface of Cu2O particles formed many ion release channels, resulting in an excellent sustained release of Cu2+ ions. PANI as a protective barrier prevented Cu2O from directly contacting the external solution and releasing Cu2+ ions. PANI had an excellent e− transfer ability as a conductive polymer, which improved the efficiency of photogenerated e− and h+ separation of Cu2O. Our results showed that the Ag–Cu2O/PANI exhibited a high long-term antibacterial activity against S. aureus and P. aeruginosa, bacterial inhibition rates of which were maintained around 78% and 80% after being stored in phosphate buffer saline solution for 30 days. In this paper, Ag–Cu2O/PANI is proposed which can enhance the photocatalytic performance of Cu2O and long-term antibacterial activity.