Michael Robin Jude Vimal, Sambandam Balaji, Muthukumar Thangavelu, Umapathy Manickam J, Manoharan Periakaruppan T
Department of Chemistry, Anna University, Chennai 600 025, India.
Phys Chem Chem Phys. 2014 May 14;16(18):8541-55. doi: 10.1039/c4cp00169a.
Silver doped zinc oxide nanoparticles are synthesized by a solution combustion method. The samples characterized by a variety of spectroscopic and other techniques clearly reveal the presence of silver nanoparticles as well as silver clusters. The silver in the two forms was identified by careful deconvolution of X-ray photoelectron spectral results. Their formation was also confirmed by the presence of plasmons, the concentration and energy of which increase on increasing silver input, indicating the presence of perpendicular excitons since aggregates of clusters are known to shift the plasmon resonances depending on their topologies. Further confirmation of clusters came from EPR (electron paramagnetic resonance), HRSEM (high resolution scanning electron microscopy) and HRTEM (high resolution transmission electron microscopy); direct proof for clusters came from matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectral measurements. The antimicrobial activity of the silver doped zinc oxide polymer nanocomposites as biomedical devices are measured by zone of inhibition. Also, samples coated on paper disk with acacia binder are evaluated by a disk diffusion method. While pure zinc oxide does not show any antimicrobial property, the activity of silver-doped zinc oxide is comparable to that of commercial antibiotics and found to be related to nanoparticulate silver. Similarly, the microbial adherence to the surface of polymer nanocomposite which mimics a biomedical device also was influenced by nanoparticles of silver. The photocatalytic water treatment was carried out using silver carrying nanoparticles with Rhodamine-B and 4-chlorophenol as model pollutants. The increased photocatalytic activity of silver containing zinc oxide as compared to pure zinc oxide nanoparticles is attributed to the synergistic display of the properties of silver nanoparticles and clusters in zinc oxide. This activity depends upon the dispersion of silver nanoparticles over the zinc oxide lattice where charge separation plays a dominant role. The mechanisms for both photocatalysis and antimicrobial activity are discussed.
通过溶液燃烧法合成了银掺杂的氧化锌纳米颗粒。用多种光谱和其他技术表征的样品清楚地显示出银纳米颗粒以及银簇的存在。通过对X射线光电子能谱结果进行仔细的反卷积分析，确定了两种形式的银。等离子体激元的存在也证实了它们的形成，随着银输入量的增加，等离子体激元的浓度和能量增加，这表明存在垂直激子，因为已知簇的聚集体会根据其拓扑结构改变等离子体激元共振。通过电子顺磁共振（EPR）、高分辨率扫描电子显微镜（HRSEM）和高分辨率透射电子显微镜（HRTEM）进一步证实了簇的存在；通过基质辅助激光解吸电离飞行时间（MALDI-TOF）质谱测量获得了簇的直接证据。通过抑菌圈测定了银掺杂氧化锌聚合物纳米复合材料作为生物医学器件的抗菌活性。此外，用阿拉伯胶粘合剂涂覆在纸盘上的样品通过纸片扩散法进行评估。虽然纯氧化锌没有显示出任何抗菌性能，但银掺杂氧化锌的活性与市售抗生素相当，并且发现与纳米颗粒银有关。同样，模拟生物医学器件的聚合物纳米复合材料表面上的微生物附着也受到银纳米颗粒的影响。以罗丹明-B和4-氯苯酚为模型污染物，使用载银纳米颗粒进行光催化水处理。与纯氧化锌纳米颗粒相比，含银氧化锌的光催化活性增强归因于银纳米颗粒和簇在氧化锌中的协同性能表现。这种活性取决于银纳米颗粒在氧化锌晶格上的分散情况，其中电荷分离起主导作用。讨论了光催化和抗菌活性的机制。
