| Diseases caused by bacterial infections and environmental pollution caused by bacteria are threatening the health of human beings.The abuse of antibiotics has induced the resistance of bacteria.The conventional antibacterial agents are gradually failing to meet the requirements of treating bacteria-induced diseases.Hence,it is vital to develop rapid and safe sterilization strategy.Photodynamic and photothermal strategies based photoresponsive nanomaterials are attracting the most attention.Photodynamic strategy is to employ reactive oxygen species（ROS）produced by materials under light irradiation to attack the bacterial membrane,while photothermal treatment is carried out by using hyperthermia produced by light-heat conversion to inactivate bacteria,the two methods are usually applied together.In this thesis,g-C3N4 was used as the starting material,which was modified after calcination,and then used to construct heterojunction by combining with a photocatalyst with photothermal effect;the antibacterial properties of the system under the synergistic effects of both photothermal action and photocatalysis have been investigated.The specific research contents are as follows:（1）Bulk g-C3N4 was prepared by calcination,which was followed by protonation through hydrothermal,and then combined with different proportions of Cu S via electrostatic interaction.The structures and phases of the composites were determined by a series of characterizations.Using photothermal curves,photoelectrochemistry measurements and PL spectra to compare the performance of different Cu S/protonated g-C3N4（Cu S/PCN）and analyze the optimal combination ratio.When the Cu S content is 20%,the composite can perform the optimized synergistic effects of both photothermal action and photocatalysis under light irradiation for 20 min.The corresponding bacteria-killing efficiency against Staphylococcus aureus and Escherichia coli is 98.23%and 99.16%,respectively.The underlying mechanism is that the bacterial membrane can be weakened by ROS and bacterial activities are inhibited by hyperthermia.（2）Porous g-C3N4 sheet was prepared by the pretreatment of melamine with nitric acid,the zeta potential of was g-C3N4 sheet changed by grafting Fe3+,and different proportions of Mo Se2 were combined with by Fe3+/g-C3N4 by columbic gravity.The morphologies of the synthesized samples were determined by SEM images.The photothermal curves showed that the photothermal effect of composites was due to presence of Mo Se2,the photoelectrochemical tests verified that the photocatalytic abilities of composites were improved.The antibacterial experiments showed that the heterostructure with Mo Se2 content of 20%had the best antibacterial performance,reflecting the cooperation of ROS and hyperthermia. |
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