Morphology modulation and performance optimization of nanopetal-based Ag-modified BiOCO as an inactivating photocatalytic material.

The use of photocatalytic technology to kill bacteria on marine vessel surface coatings has been paid more attention by research scholars. In this paper, petal-like microspheres with Ag nanoparticles were prepared by a simple one-step process combining the hydrothermal method and photodeposition. The 0.7% Ag/BiOCO composite photocatalyst exhibited the highest photocatalytic efficiency for bacterial removal under visible light irradiation and had the highest photogenerated carrier separation efficiency, and the sterilization rate was doubled compared with that of pure BiOCO, reaching 95%. Using X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy, the existence of Ag nanoparticles was confirmed, and their size was approximately 10 nm. The surface plasmon resonance (SPR) effect of Ag nanoparticles was investigated by ultraviolet-visible diffuse reflectance spectroscopy (DRS). It was shown that the surface plasmon resonance effect of Ag improved the spectral utilization of the Ag/BiOCO composite photocatalyst and enhanced the stability of the catalyst. This caused the Ag/BiOCO composite photocatalyst to have superior photocatalytic activity to pure BiOCO. The results of electrochemical impedance characterization and transient photocurrent response show that 0.7% Ag/BiOCO has a high efficiency of photogenerated carrier separation. By the free radical capture test, hydroxyl radicals were the primary active substance, and Ag improved the photocatalytic sterilization activity.