石墨烯量子点/Ce-2-甲基咪唑的制备及其宽光谱抗菌性能

Preparation of graphene quantum dots/Ce-2-methylimidazole heterojunction and its wide-spectrum antibacterial activity

光催化作为一种新型抗菌方式引起广泛关注,开发高效可见光催化剂是热点研究方向之一。本文通过一种绿色化学法合成了石墨烯量子点(GQDs),并在室温下以GQDs、硝酸铈、2-甲基咪唑(2MI)为原料,采用一锅沉淀法合成了GQDs/Ce-2MI。调整GQDs的起始添加量,得到不同GQDs负载量的复合光催化剂,通过光电化学测试发现,25vol%GQDs/Ce-2MI样品具有高的光电流响应。进一步固定2MI为有机配体,制备不同中心金属离子(Mn^(+):Co^(2+)、Fe^(2+)、Fe^(3+))的M-2MI,并进行对比。在可见光照射下,以大肠杆菌(E.coli)为目标菌种,考察了不同催化剂的抗菌性能。研究发现,GQDs/Ce-2MI的抗菌性能最佳,可见光照射60 min后,实现超过99%的灭菌效果。以优选GQDs/Ce-2MI为光催化剂,研究了光源波长、不同菌种的影响。结果表明,GQDs/Ce-2MI在较宽光谱范围内有较好的抗菌能力,对金黄色葡萄球菌(S.aureus)也具有普适性抗菌效果。通过猝灭剂实验推测对E.coli消灭的主要活性物种为空穴(h+)和羟基自由基(•OH)。

As a new antibacterial method,photocatalysis has attracted extensive attention.The development of high-efficiency visible light catalyst is one of the hot research directions.In this work,graphene quantum dots(GQDs)were synthesized by a green-chemical method.GQDs/Ce-2MI was obtained via one-pot precipitation method at room temperature using GQDs,cerium nitrate and 2-methylimidazole(2MI)as raw materials.Different ratios of GQDs/Ce-2MI samples were obtained by controlling the initial amount of GQDs solution.Through photoelectrochemical test,it is found that 25vol%GQDs/Ce-2MI displayed high photocurrent response performance.Furthermore,using 2MI as fixed organic ligand,M-2MI with different central metal ions(Mn^(+):Co^(2+),Fe^(2+),Fe^(3+))were synthesized and compared.Under visible light irradiation,the antibacterial properties of different catalysts were investigated using Escherichia coli(E.coli)as target strain.The results indicate that GQDs/Ce-2MI displays the optimal antibacterial performance.After 60 min of visible light irradiation,more than 99%sterilization effect can be achieved.Using the optimized GQDs/Ce-2MI as photocatalyst,the effects of light source wavelength and different bacterial species were studied.The results indicate that GQDs/Ce-2MI has good antibacterial ability in a wide spectrum range and universal antibacterial effect toward Staphylococcus aureus(S.aureus).Through the quencher experiments,it can be speculated that the main active species for the inactivation of E.coli are holes(h+)and hydroxyl radicals(•OH).