Facile synthesis of binary metal substituted copper oxide as a solar light driven photocatalyst and antibacterial substitute

This work presents the synthesis of Cu_0.95Mn_0.05O (CMO), Cu_0.95Ag_0.05O (CAO), and Cu_0.9Mn_0.05Ag_0.05O (CMAO) samples via wet chemical route for photocatalytic and antibacterial applications. The phase, morphology, chemical composition, and absorption range of the transition metal substituted CuO samples were investigated using various techniques such as PXRD, FESEM, EDX, and UV/Visible spectroscopy . The photocatalytic and antibacterial aptitude of all the synthesized samples was tested using methylene blue (MB) and bacterial strains. The results of application studies showed that the CMAO sample has a greater potential for dye degradation and bacterial strain destruction because of its long-lived photo-generated reactive species. More precisely, among all the synthesized samples, the CMAO sample showed excellent photocatalytic activity and degraded 83.9% dye at a higher rate constant value (0.0127 min^?1). Moreover, the CMAO sample also showed better bactericidal activity against Gram-positive (S. aureus) and Gram-negative bacterial strains (E. coli). Actually, components of the bacterial cell membrane are also organic like organic dyes, so they are likely to degrade by photo-generated species. The results revealed that binary metal substituted CuO (CMAO) has an excellent ability to kill bacteria and eliminate toxic dyes from industrial effluents.     

Fabrication characterization and activity of a solar light driven photocatalyst: cerium doped TiO2 magnetic nanofibers

A novel magnetic separable composite photocatalytic nanofiber consisting of TiO2 as the major phase, CeO(2-y) and CoFe2O4 as the dopant phase was prepared by sol-gel method and electrospinning technique, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectrum (UV-vis DRS) and vibrating sample magnetometer (VSM). The photocatalytic activity of the resultant CoFe2O4-TiO2 and CeO(2-y)/CoFe2O4-TiO2 nanofibers was evaluated by photodegradation of methylene blue (MB) in an aqueous solution under xenon lamp (the irradiation spectrum energy distribution is similar to sunlight) irradiation in a photochemical reactor. The results showed that the dopant of Ce could affect the absorbance ability and photo-response range. The sample containing 1.0 wt% CeO(2-y) exhibited the highest degradation with 35% for MB under simulate solar light irradiation. Furthermore, the as-synthesized composite photocatalytic nanofibers could be separated easily by an external magnetic field, thus it might hold potential for application in wastewater treatment.     

Copper nanoparticles catalysed an efficient one-pot multicomponents synthesis of chromenes derivatives and its antibacterial activity

In this study, copper nanoparticles (Cu NPs) were synthesised by using diethylenetriamine as a protective agent in chemical reduction method. The obtained nanoparticles were characterised by various spectroscopic techniques like powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR), UV–visible spectroscopy, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal analysis (TG/DTA). The structure and composition were estimated by PXRD, FTIR, EDS, UV–visible and TG/DTA techniques, while particles size and morphology behaviours were investigated by SEM and TEM instrumentation. A noteworthy, average particle size of nanoparticles was found around 40 nm with spherical shapes. Furthermore, the applications part of NPs were studied as a catalyst for one-pot solvent-free green synthesis of 3,4-dihydropyrano[c]chromenes from different aromatic aldehydes, malonitrile and 4-hydroxycoumarin by stirring at 80 °C. Moreover, the antibacterial properties of NPs were assessed in vitro against human bacterial pathogen such as Staphylococcus aureus, Escherichia coli, Klebsiella sp. and Pseudomonas aruginosa using agar well diffusion method. Gram positive bacteria S. aureus (18 mm) exhibited a maximum zone of inhibition at 60 µg/ml of Cu NPs. Nonetheless, antibacterial activities of Cu NPs (10–100 µg) were compared with four well-known antibiotics likes amikacin (30 mcg), ciprofloxacin (5 mcg), gentamicin (5 mcg) and norfloxacin (10 mcg). This study indicates that Cu NPs exhibited a strong antibacterial activity against all the test pathogens even at lower concentration.     

Hollow ZnO from assembly of nanoparticles: photocatalytic and antibacterial activity

Hollow shells of ZnO were formed by the assembly of nanoparticles using PEG 400 wherein PEG-400 acted like both a solvent and a structure directing agent. The structure, morphology and optical properties were characterized by using PXRD, SEM, TEM and absorption studies. The hollow shells were found to possess high crystallinity with a surface area of 8 m² g^?1. The assembly was formed by nanoparticles ranging from 50 to 60 nm, whereas the size of the hollow shell ranged from 500 nm to 1 micron. Photocatalytic activity of these nanostructures was studied using Rhodamine B (RhB) and methyl orange (MO). Nearly 99% of the RhB dye was found to be degraded in 60 min while for MO, the degradation was 97% in 50 min. The pseudo-first-order rate constant was calculated as 0.072 min^?1 for the degradation of RhB and 0.075 min^?1 for the degradation of MO. The hollow shells were found to exhibit significant bacterial inhibiting efficacy at a low concentration of the particles. Comparative studies were carried out for photodegradation of Rhodamine B dye and antibacterial activity using spherical particles of ZnO and assembly of particles to form rods of ZnO. The results indicated that these hollow nanostructures could be used as a potential catalyst for the removal of dyes from water and as an antibacterial agent.     

Novel solar light driven photocatalyst, zinc indium vanadate for photodegradation of aqueous phenol

In the present investigation, we have demonstrated the synthesis of novel photocatalyst, zinc indium vanadate (ZIV) by solid-solid state route using respective oxides of zinc, indium and vanadium. This novel photocatalyst was characterized using XRD, FESEM, UV-DRS and FTIR in order to investigate its structural, morphological and optical properties. XRD clearly shows the formation of phase pure ZIV of triclinic crystal structure with good crystallinity. FESEM micrographs showed the clustered morphology having particle size between 0.5 and 1 μm. Since, optical study showed the band gap around 2.8 eV, i.e. in visible region, we have performed the photocatalytic activity of phenol degradation under visible light irradiation. The photodecomposition of phenol by ZIV is studied for the first time and an excellent photocatalytic activity was obtained using this novel photocatalyst. Considering the band gap of zinc indium vanadate in visible region, it will also be the potential candidate for water splitting.     

Process optimisation for green synthesis of ZnO nanoparticles and evaluation of its antimacrofouling activity

In recent years, considerable attention has been given to the plant‐mediated synthesis of nanoparticles because it is an eco‐friendly method compared to the synthesis by chemical route. This study aims to optimise the biosynthesis of zinc oxide nanoparticles (ZnO‐NPs) mediated by coconut water using response surface methodology (RSM). The effects of the individual variables (concentration of coconut water, temperature and time) and their interactions during the biosynthesis of ZnO‐NPs were determined by RSM employing Box–Behnken design. The variables selected were tested by a 17‐run experiment and quadratic model was used for the analysis of the results. The accuracy of the model was confirmed by the coefficient of determination (R ²) value of 0.9968. The significance of the regression model was found to be high which is validated by the low probability value of P  < 0.0001. The ZnO‐NPs thus synthesised was evaluated for its antimacrofouling activity against mollusks using in‐vitro foot‐adherence bioassay. The results demonstrated the potential of biosynthesised ZnO‐NPs in inhibiting fouling induced due to the test organisms.Inspec keywords: nanoparticles, antibacterial activity, response surface methodology, zinc compounds, regression analysis, design of experiments, biotechnologyOther keywords: plant‐mediated synthesis, eco‐friendly method, biosynthesis, zinc oxide nanoparticles, coconut water, response surface methodology, RSM, Box–Behnken design, quadratic model, regression model, antimacrofouling activity, biosynthesised ZnO‐NPs, process optimisation, green synthesis, ZnO nanoparticles     

Bio-mechanochemical synthesis of silver nanoparticles with antibacterial activity

By using a bio-mechanochemical approach combining mechanochemistry (ball milling) and green synthesis for the first time, silver nanoparticles (Ag NPs) with antibacterial activity were successfully synthesized. Concretely, eggshell membrane (ESM) or Origanum vulgare L. plant (ORE) and silver nitrate were used as environmentally friendly reducing agent and Ag precursor, respectively. The whole synthesis took 30?min in the former and 45?min in the latter case. The photon cross-correlation measurements have shown finer character of the product in the case of milling with Origanum. UV–Vis measurements have shown the formation of spherical NPs in both samples. TEM study has revealed that both samples are composites of nanosized silver nanoparticles homogenously dispersed within the organic matrices. It has shown that the size and size distribution of the silver nanoparticles is smaller and more uniform in the case of eggshell membrane matrix implying lower silver mobility within this matrix. The antibacterial activity was higher for the silver nanoparticles synthesized with co-milling with Origanum plant than in the case of milling with eggshell membrane.     

形貌和光照条件对ZnO抗菌性能的影响

检测了四针状氧化锌晶须、纳米氧化锌和普通工业级氧化锌的抗菌性能,比较了形貌和光照条件对ZnO抗菌性能的影响,并研究了ZnO对不同菌种的抗菌性能差异.结果表明,Zno形貌对其抗菌性能有较大影响,有光条件下ZnO抗菌性能大于无光条件下,3种ZnO对大肠杆菌的抗菌性能均比对金黄色葡萄球菌好.     

Preparation,characterisation and activity evaluation of CaCO3/ZnO photocatalyst

The photocatalyst CaCO₃/ZnO with high activity was prepared by coprecipitation method using (NH₄)₂CO₃, Zn(NO₃)₂ and Ca(NO₃)₂ as raw materials. The photocatalyst was characterised by X-ray powder diffraction, terephthalic acid photoluminescence probing technique (TA-PL), UV–vis diffuse reflectance spectroscopy and the fluorescence emission spectra. The photocatalytic activity of the photocatalyst was evaluated by photocatalytic oxidation of methyl orange and rhodamine B. The results showed that the photocatalytic activity of the photocatalyst was much higher than that of pure ZnO. The best mole ratio of Ca/Zn in the sample was 1?:?2, and its intensity of TA-PL was the strongest. The effect of heat treatment condition on the photocatalytic activity of the photocatalyst was investigated. The best preparation condition was about 650°C for 7?h. Compared with pure ZnO, the photoabsorption wavelength range of the CaCO₃/ZnO extends towards visible light and improves the utilisation of the total spectrum. The possible mechanisms of influence of CaCO₃ on the photocatalytic activity of CaCO₃/ZnO were also discussed.     

Structural, optical, photo catalytic and antibacterial activity of ZnO and Co doped ZnO nanoparticles

A systematic investigation on the structural, optical, photo catalytic and antimicrobial properties of pure and cobalt doped ZnO nanoparticles synthesized by Co-precipitation method is presented. X-ray diffraction analysis of these samples showed the formation of phase pure nanoparticles with wurtzite ZnO structure. Optical studies showed a blue shift in the absorbance spectrum with increasing the doping concentration. The Methylene Blue (MB) decomposition rate of the synthesized pure ZnO and cobalt doped ZnO nanoparticles were studied under the UV region. In the UV region, synthesized pure ZnO and cobalt doped ZnO decomposed Methylene Blue (MB). However, the MB decomposition rate obtained using pure ZnO was much higher than that by doped ZnO. The antibacterial property test was carried out via disk diffusion method, and the result indicated antibacterial activity of the prepared samples.     

Low-temperature synthesis of ZnO nanoparticles for inverted polymer solar cell application

Zinc oxide (ZnO) nanoparticles were synthesized by a simple wet chemical method at low temperature. Morphologies, crystalline structure, and optical transmission of ZnO nanoparticles were investigated. The results showed that the average diameter of as-synthesized ZnO nanoparticles was about 4.9 nm, the nanoparticles were wurtzite-structured (hexagonal) ZnO and had optical band gap of 3.28 eV. Very high optical transmission (>80 %) in visible light region of ZnO nanoparticulate thin films was achieved. Furthermore, an inverted polymer solar cell consisted of ZnO nanoparticles and polymer were fabricated. The device exhibited an open circuit voltage (V_oc) of 0.50 V, a short circuit current density (J_sc) of 1.76 mA/cm², a fill-factor of 38 %, and a power conversion efficiency of 0.42 %.     

Ginkgo leaves extract-assisted synthesis of ZnO/CuO nanocrystals for efficient UV-induced photodegradation of organic dyes and antibacterial activity

Journal of Materials Science: Materials in Electronics - Biogenic nanocrystals (NCs) were synthesized from Ginkgo biloba&nbsp;leaf extract (GLE) and applied as photocatalytic and antibacterial...     

Adsorption and solar light activity of transition-metal doped TiO<Subscript>2</Subscript> nanoparticles as semiconductor photocatalyst

There is an eminent interest to improve the photoactivity of TiO₂ nanostructures via doping with mid-band gap donors or acceptors to achieve a high solar absorption. In the present work, Cr- and V-doped TiO₂ nanoparticles were prepared via a facile chemical vapor synthesis method. The effect of the transition metals (TM) on the solar light activity of the semiconductor nanoparticles as photocatalyst was examined by degradation of methylene blue and acid red 27. Induced coupled plasma and X-ray photoelectron spectroscopy analyses indicated high efficiency of the doping process in the hot wall reactor without surface covering of the TiO₂ nanoparticles by the dopants. Diffuse reflectance spectroscopy also revealed a red shift of the absorption edge of the TiO₂ nanoparticles with increasing dopant concentration. Analysis of the photoactivity of the synthesized nanoparticles under sun light showed an increase in the primary absorption of dye molecules on the surface of Cr- and V-doped TiO₂ nanoparticles whereas the degradation rate was found to depend on the type and concentration of the dopants. A high photoactivity is obtained at 0.2 at% V concentration. The mechanism of photoactivity is discussed based on the effect of TM on the absorption edge of the semiconductor.     

高效光催化剂的制备及应用研究

制备了一种高效光催化剂,通过采用溶胶-凝胶法,利用非金属离子S和稀土离子Sm共掺杂改性纳米TiO2。以降解甲基橙模拟染料废水为目标,通过UV-vis、XRD、TEM等手段考察了其在紫外光下的光催化活性。结果表明,共掺杂的光催化活性要明显优于单掺杂和不掺杂的,尤以煅烧温度500℃,n(S)∶n(Sm)∶n(Ti)=15∶0.1∶1时,紫外光下光催化活性最佳。     

Surfactant assisted solvothermal synthesis of ZnO nanoparticles and study of their antimicrobial and antioxidant properties

This study demonstrated a solvothermal method of growth of three different morphologies of zinc oxide nanoparticles(ZnO NPs): i) flower-like nanorod and nanoflakes, ii) assembled hierarchical structure,and iii) nano granule. Oleic acid(C_(18)H_(34)O_2), gluconic acid(C_6H_(12)O_7) and tween 80(C_(64)H_(124)O_(26)) were used as surfactant/capping/reducing agent for the formation of different morphologies of nanoparticles.The as-synthesized ZnO NPs were characterized by different physicochemical techniques such as UV–vis(UV–vis) spectroscopy, X-ray diffraction(XRD), fourier transform infrared spectroscopy(FTIR), field emission scanning electron microscopy(FE-SEM), energy dispersive X-ray(EDX) analysis and dynamic light scattering(DLS) studies. Further, the antioxidant and antimicrobial activity of these nanostructures was evaluated. The antioxidant activity of these nanostructures was assessed via 2,2-diphenyl,1-1 picrylhydrazyl(DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)(ABTS) and H_2O_2 free radical scavenging activity. The in vitro antimicrobial activity of the obtained nanostructures was demonstrated against both gram negative(Escherichia coli) and gram positive(Staphylococcus aureus) bacterial genera.This study revealed antioxidant and antimicrobial properties of different structures of ZnO NPs suggesting their biomedical and industrial applications.     

Phase- and size-controllable synthesis with efficient photocatalytic activity of ZnS nanoparticles

We report a simple solution-based method to synthesize phase- and size-controllable ZnS nanoparticles at low temperature. Cubic ZnS (c-ZnS) and hexagonal ZnS nanoparticles (h-ZnS) were obtained by heating an aqueous solution of Zn(NO₃)₂·6H₂O and Na₂S₂O₃·5H₂O at different temperatures. When the system was heated at 65 °C for 24 h, hexagonal crystal structure of ZnS nanoparticles, with size of 50–350 nm, was obtained, as confirmed by X-ray diffraction and selected-area electron diffraction. When the reaction temperature was 100 °C under hydrothermal condition, c-ZnS nanoparticles were obtained and exhibited monodisperse nanoparticles with average size of 4 nm. Proper rate of S releasing tuned by the variation of pH value is believed to be critical to stabilize the hexagonal ZnS nanoparticles. Compared with large size of h-ZnS nanoparticles, c-ZnS nanoparticles show higher photocatalytic activity in degrading methyl orange (MO). The degradation efficiency of c-ZnS nanoparticles reaches 97% under UV irradiation for 120 min. The good ultraviolet absorbing ability, charge separation property, and large surface area of c-ZnS nanoparticles are believed to have a positive impact on improving the degradation rate and degradation efficiency of MO.     

Green synthesis of nickel oxide nanoparticles and its photocatalytic degradation and antibacterial activity

Journal of Materials Science: Materials in Electronics - In the present work, we report the biosynthesis of Nickel oxide (NiO) nanoparticles using Senna auriculata aqueous flower extract and their...     

Direct synthesis of monodispersed ZnO nanoparticles in an aqueous solution

Monodispersed ZnO nanoparticles with mesopores were successfully prepared via a simple route through the transformation of Zn(NH₃)₄²⁺ precursor in the presence of sodium oleate and hydrazine at 80 °C with the pH of 8.5. Hydrazine and sodium oleate were used to control the size at 30-60 nm and to improve dispersion properties of ZnO nanoparticles. The samples were characterized by TEM, XRD, IR and TG-DTA, and the results suggest that the grains are composed of ZnO and a small quantity of oleate. The oleate plays an important role in preventing the ZnO nanoparticles from aggregating.