Preparation of graphene quantum dots/Ce-2-methylimidazole heterojunction and its wide-spectrum antibacterial activity
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摘要: 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+: Co2+、Fe2+、Fe3+)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)。Abstract: 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+: Co2+, Fe2+, Fe3+) 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).
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Key words:
- photocatalysis /
- antibacterial /
- graphene quantum dots /
- Ce-2-methylimidazole /
- wide spectrum
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图 6 Ce-2MI、GQDs和GQDs/Ce-2MI等对E. coli的抗菌效果 (a),E. coli抗菌照片对比 (b),Ce-2MI、GQDs和25vol%GQDs/Ce-2MI对S. aureus的抗菌效果 (c)
Figure 6. Antibacterial effect of E. coli by Ce-2MI, GQDs and GQDs/Ce-2MI (a), comparison of E. coli antibacterial photos (b) and antibacterial effect of S. aureus by Ce-2MI, GQDs and 25vol%GQDs/Ce-2MI (c)
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[1] LI P, LI J Z, FENG X, et al. Metal-organic frameworks with photocatalytic bactericidal activity for integrated air cleaning[J]. Nature Communications,2019,10:2177. doi: 10.1038/s41467-018-07709-6 [2] LI X, HAO H, LANG X. Thiazolo[5, 4d] thiazole linked conjugated microporous polymer photocatalysis for selective aerobic oxidation of amines[J]. Journal of Colloid and Interface Science, 2021, 593: 380-389. [3] LANG X, CHEN X, ZHAO J. Heterogeneous visible light photocatalysis for selective organic transformations[J]. Chemical Society Reviews,2013,43:473-486. [4] QIN J, WANG S, WANG X. Visible-light reduction CO2 with dodecahedral zeolitic imidazolate framework ZIF-67 as an efficient co-catalyst[J]. Applied Catalysis B: Environmental,2017,209:476-482. doi: 10.1016/j.apcatb.2017.03.018 [5] GAO Q, LIN D, FAN Y, et al. Visible light induced photocatalytic reduction of Cr(VI) by self-assembled and amorphous Fe-2MI[J]. Chemical Engineering Journal,2019,374:10-19. doi: 10.1016/j.cej.2019.05.151 [6] 卫思颖, 马建中, 范倩倩. 量子点/TiO2复合光催化材料的研究进展[J]. 复合材料学报, 2021, 38(3): 712–721.WEI Siying, MA Jianzhong, FAN Qianqian. Research advances on quantum dots/TiO2 composite photocatalytic materials[J]. Acta Materiae Compositae Sinica, 2021, 38(3): 712-721(in Chinese). [7] ROUSHANI M, MAVAEI M, RAJABI H R. Graphene quantum dots as novel and green nano-materials for the visible light-driven photocatalytic degradation of cationic dye[J]. Journal of Molecular Catalysis A: Chemical,2015, 409:109-112. [8] CHEN W, LI D, TIAN L, et al. Synthesis of graphene quantum dots from natural polymer starch for cell imaging[J]. Green Chemistry,2018,20:4438-4442. doi: 10.1039/C8GC02106F [9] TANG L, JI R, CAO X, et al. Deep ultraviolet photoluminescence of water-soluble self-passivated graphene quantum dots[J]. ACS Nano,2012,6:5102-5110. doi: 10.1021/nn300760g [10] XIAO J, HAN L, LUO J, et al. Integration of plasmonic effects and schottky junctions into metal-organic framework composites: Steering charge flow for enhanced visible-light photocatalysis[J]. Angewandte Chemie International Edition,2018,57:1103-1107. doi: 10.1002/anie.201711725 [11] WANG Q, GAO Q Y, AL-ENIZI A M, et al. Recent advances in MOF-based photocatalysis: Environmental remediation under visible light[J]. Inorganic Chemistry Frontiers,2020,7:300-339. doi: 10.1039/C9QI01120J [12] LI Y, WANG X, WANG C, et al. S-TiO2/UiO-66-NH2 compo-site for boosted photocatalytic Cr(VI) reduction and bisphenol A degradation under LED visible light[J]. Journal of Hazardous Materials,2020,399:123085-123099. doi: 10.1016/j.jhazmat.2020.123085 [13] HE J, XU Y, WANG W, et al. Ce(III) nanocomposites by partial thermal decomposition of Ce-MOF for effective phosphate adsorption in a wide pH range[J]. Chemical Engineering Journal,2020,379:122431. doi: 10.1016/j.cej.2019.122431 [14] DU X, YI X, WANG P, et al. Enhanced photocatalytic Cr(VI) reduction and diclofenac sodium degradation under simulated sunlight irradiation over MIL-100(Fe)/g-C3N4 heterojunctions[J]. Chinese Journal of Catalysis,2019,40:70-79. doi: 10.1016/S1872-2067(18)63160-2 [15] FU Y J, ZHANG K J, ZHANG Y, et al. Fabrication of visible-light-active MR/NH2-MIL-125(Ti) homojunction with boosted photocatalytic performance[J]. Chemical Engi-neering Journal,2021,412:128722-128733. doi: 10.1016/j.cej.2021.128722 [16] MA Y, TANG Q, SUN W, et al. Assembling ultrafine TiO2 nanoparticles on UiO-66 octahedrons to promote selective photocatalytic conversion of CO2 to CH4 at a low concentration[J]. Applied Catalysis B: Environmental,2020,270:118856. doi: 10.1016/j.apcatb.2020.118856