How vertically oriented nanotubes grow on aluminum foil?4 answersVertically aligned carbon nanotubes (VA-CNTs) can be grown on aluminum foil through various methods. One approach involves synthesizing VA-CNTs on Al foil using the Floating Catalyst Chemical Vapor Deposition (FCCVD) method at 610 °C, with ethanol as the carbon source and ferrocene as the catalyst. Another method is the Aerosol-Assisted Catalytic Chemical Vapour Deposition (CCVD) process, which utilizes acetylene as the carbon source and ferrocene as the catalyst precursor, operating at 615 °C to obtain dense forests of VACNTs on Al foil. Additionally, VA-CNTs can be grown from Langmuir–Blodgett (LB) films with accumulated nanoparticles, showing different growth rates based on the size of the catalyst nanoparticles and the catalyst area ratio. These methods demonstrate the feasibility of growing vertically oriented nanotubes on aluminum foil for various applications.
What are different ways of synthesizing zinc oxide nanoparticles using plants?4 answersDifferent ways of synthesizing zinc oxide nanoparticles using plants include using the aerial extract of Ranunculus multifidus plant, fruit and leaf extracts of Citrullus colocynthis, methanolic extract of Lawsonia inermis L. seeds, and spinach tree, Cnidoscolus aconitifolius. These plant extracts act as reducing agents and stabilizers for the biosynthesis of zinc oxide nanoparticles. The synthesis methods involve using different solvents such as aqueous, n-hexane, methanol, and ethyl acetate to prepare the extracts. The nanoparticles are characterized using techniques such as thermogravimetric analysis, X-ray diffraction, UV spectroscopy, scanning electron microscopy, and gas chromatography-mass spectroscopy. The synthesized zinc oxide nanoparticles show various properties and applications, including antibacterial activity, antioxidant activity, antifungal activity, cytotoxic activity, and potential use as nanofertilizers.
How does zinc oxide nanoparticles affect the growth of bacteria?5 answersZinc oxide nanoparticles (ZnO NPs) have been found to affect the growth of bacteria in various ways. The antimicrobial activity of ZnO NPs against Xanthomonas oryzae pv. oryzae (Xoo) pathotype 0.0 was observed, with higher concentrations of ZnO NPs leading to a decrease in the number of viable cells. Pseudomonas aeruginosa PCN-2 showed inhibited intracellular metabolism and stimulated antioxidant defense capability under ZnO NPs exposure, leading to deficient energy for aerobic denitrification. Bacillus cereus and Lysinibacillus macroides exhibited increased growth rate and tolerance potential at lower concentrations of ZnO NPs against heavy metals (HMs), while higher concentrations of ZnO NPs resulted in HM accumulation in bacterial cells and significant impact on bacterial morphology. Proteus vulgaris showed sensitivity to ZnO NPs, with higher concentrations causing bacterial growth inhibition and oxidative stress effects. ZnO NPs synthesized using Emblica officinalis displayed significant antibacterial activity against Streptococcus pyogenes, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa, and also showed high anti-biofilm activity.
How can the different methods to fabricate ZnO nanoflowers be improved?5 answersDifferent methods to fabricate ZnO nanoflowers can be improved in several ways. One approach is to use a sonochemical method, which is a simple, environmentally friendly, low-cost, and rapid method for synthesis. Another improvement is to fabricate Au-modified ZnO nanoflowers, which exhibit excellent gas sensing performance due to their regular and ordered three-dimensional flower-like structures. Additionally, the use of fungi extracts as reducing agents and stabilizers can enhance the synthesis of ZnO nanoflowers, resulting in particles with a large effective surface and high crystallinity. The morphological and photovoltaic properties of ZnO thin films can be controlled by adjusting the presence of NH3 and different additives, leading to improved energy conversion efficiencies in dye-sensitized solar cells. Finally, the ultimate morphology of ZnO flower-like nanostructures can be controlled by adjusting the amount of surfactant added to the precursor, which affects the thickness and shape of the petals.
How to increase the band gap of ZnO?5 answersTo increase the band gap of ZnO, several approaches have been explored. One method is to introduce dopants into the ZnO structure. Doping with transition metals such as Cr, Fe, Mn, and Nb has been found to decrease the band gap and shift it towards the visible region. Another approach is to reduce the dimensionality of the ZnO film. Studies have shown that reducing the thickness and orientation of the film can enhance the band gap, resulting in a wider range of optoelectronic applications. Additionally, the properties of ZnO films can be influenced by the oxidation temperature and the nature of the film support material. Overall, these methods offer potential strategies for increasing the band gap of ZnO and tailoring its optoelectronic properties.
What are the applications of ZnO nanowalls?5 answersZnO nanowalls have various applications. They exhibit higher photocatalytic efficiency compared to ZnO nanowires for the degradation of methylene blue (MB) and tetracycline capsules (TC) under UVC light irradiation. ZnO nanowalls with Al-doped can improve the separation of photogenerated electron-hole pairs, enhancing their photocatalytic activity. They also demonstrate excellent recycling and reuse capacity for multiple cycles of MB and TC degradation. In addition, ZnO nanowalls have potential applications in the field of energy, such as in supercapacitors and Li-ion batteries. They are also used in various biological applications, including anti-bacterial, anti-tumor, anti-inflammation, skin care, biological imaging, and food packaging. ZnO nanowalls have a large specific surface area, powerful adsorption ability, and large catalytic efficiency, making them suitable for the preparation of electrochemical sensors and biosensors. They are advantageous for applications in sensing, photocatalysis, functional textiles, and cosmetic industries.