Study on photocatalytic sterilization performance and mechanism of Fe-SnO2 / g- C3N4 heterojunction material
A novel visible light catalytic material, modified g-C3N4 with Fe doped SnO2 (Fe-SnO2/g-C3N4), was prepared by a chemical precipitation-ball milling-baking method. This photocatalytic material showed sterilization performance for Escherichia coli and Staphylococcus aureus under the conditions of daylight lamp, natural sunlight, near ultraviolet light and simulated sunlight, among which the sterilization performance enhancing effect was most prominent under daylight lamp, suggesting practical application prospect. Scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were used to analyze the structure of Fe-SnO2/g-C3N4. It was found that Fe-SnO2 was uniformly dispersed on g-C3N4, forming a new type of porous layered heterojunction, which increases the surface activity and the specific surface area. Fe doping further regulates the energy band structure and promotes the Z-scheme electron conduction capability of the Fe-SnO2/g-C3N4 heterojunction. The main free radicals that perform sterilization are •OH and •O2. Based on the biochemical structure of the bacteria, the charge Z-scheme conduction sterilization mechanism is proposed from the perspectives of free radical generation energy level, biochemical reaction energy and chemical bond energy.