Fabrication of Ag–Cu2O/PANI nanocomposites for visible-light photocatalysis triggering super antibacterial activity

Abstract

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.