Low‐cost 0D and 2D carbon material co‐decorated titanium dioxide ternary heterojunction for rapid and efficient bacteria killing under visible light

Abstract Recently, the issue of bacterial resistance has gotten worse because of the overuse of antibiotics. The newborn superbacteria, such as vancomycin‐resistant bacteria, were hard to kill, inspiring researchers to find new ways to kill the bacteria efficiently. TiO 2 was used as an efficient photocatalyst for water splitting and pollutant degradation. However, the weak efficiency limited the application to solve the drug‐resistance problem. Consequently, the incorporation of low‐cost 0D carbon quantum dots (CQDs) and 2D graphene oxide (GO) was pursued to amplify the visible light absorption capabilities of TiO 2 and thereby elevate its photocatalytic activity. After forming the heterogeneous interface of CQDs and TiO 2 , CQDs converted part of visible light into wavelength less than 400 nm using the up‐conversion property. The modification of CQDs enabled electrons to be easily transferred from the conduction band of CQDs to the conduction band of TiO 2 . Meanwhile, GO can act as an electron acceptor, reduce the recombination efficiency of holes and electrons, and transfer the photogenerated electrons in the redox reaction in the heterogeneous interface. Because of the excellent absorption of GO, TiO 2 /CQDs/GO reached 57.8°C after 20 min irradiation under 1.5 times sunlight, which provided a prerequisite for photodynamic antibacterial therapy/photothermal antibacterial therapy synergistic antibacterial potential. TiO 2 /CQDs/GO possessed an antibacterial efficiency as high as 99.3% toward Staphylococcus aureus which has a bright future in disinfection in vivo and medical devices as well as water sterilization.