Preparation of a high-efficiency low-toxicity CdS/C60 bactericide and investigation of the mechanism

Abstract

Photocatalysis is considered as a promising technology to solve bacterial contamination, but the development of efficient photocatalysts with a strong generalizable light response remains a challenge. CdS has a suitable energy gap and good response to visible light, but the photogenerated carrier separation efficiency is low, and the photo-corrosion phenomenon leads to the significant release of Cd²⁺. In this paper, the CdS/C₆₀ composite photocatalyst bactericide is synthesized via a simple one-step hydrothermal method. Testing via EIS, I–t, PL, and TRPL show that the C₆₀ in the composite improves the hole–electron separation efficiency of CdS, resulting in a better photocatalytic performance. The complete inactivation of S. aureus and E. coli can be achieved within 40 min and 120 min, respectively, by dispersing 100 μg mL⁻¹ of CdS/C₆₀-2 in a diluted bacterial solution under simulated visible-light irradiation. Combined with ESR, SEM, fluorescence staining, DNA gel electrophoresis and ICP technology, it is believed that the high inactivation of bacteria is attributed to the ROS produced during the photocatalytic process, which destroy the integrity of the bacterial cell membrane and further destroy the DNA inside the bacteria, thus causing bacterial inactivation, rather than the inactivation being caused by Cd²⁺ toxicity.