A layer of TiO ₂ nanotube (TNT) arrays with a thickness of 13 μ m is synthesized by a two-step anodic oxidation from Ti metal foil. Surface charged Ag nanoparticles (NPs) are prepared by chemical reduction. After a pretreatment of the TNT arrays by acetone vapor, Ag NP filled TNT arrays can be achieved by electrophoretic deposition (EPD). Effects of the applied voltage during EPD such as DC–AC difference, frequency and waveform are investigated by quantitative analysis using atomic absorption spectroscopy. The results show that the best EPD condition is using DC 2 V + AC 4 V and a square wave of 1 Hz as the applied voltage. Back illuminated dye-sensitized solar cells are fabricated from TNT arrays with and without Ag NPs. The efficiency increased from 3.70% to 5.01% by the deposition of Ag NPs.

In this work we propose a facile method of preparing cost-effective clay-metaloxide/metal (CuO/Ag and ZnO/Ag) composite pellets for an efficient water purification technique. Clay, with intrinsic antibacterial activity, served as a membrane support for different metaloxide/Ag nanoparticles (NPs) concentrations (2.5, 5 and 10 wt.%), as the active fillers. The effect of time (24 and 48 h) on the bactericidal activity of these pellets was also monitored. The clay–nanocomposite pellets were characterized using: X-ray diffraction, X-ray fluorescence, scanning electron microscopy, transmission electron microscopy, ultraviolet–visible (UV–Vis) spectrophotometry and nitrogen desorption analysis. The antibacterial activity performance was tested using E. coli and S. aureus strains of ATCC25922 and ATCC25923, respectively, in two aqueous media (nutrient broth and nutrient-free) by the colony-forming unit method. The results showed that the clay-CuO/Ag composite with a bandgap (1.24 eV) exhibited overall best performance under all conditions and time factors of ~100% efficiency in nutrient-free medium for all concentrations and times and 20–40% efficiency in nutrient broth for 24 h. The clay-ZnO/Ag with a bandgap of 2.88 eV showed no bactericidal activity in both media, except for that with 10 wt.% ZnO/Ag which showed 100% efficiency in nutrient-free medium after 24 h. All the synthesized composites showed 100% bactericidal efficiency in nutrient free medium after 48 h. These results indicate that, the clay/metaloxide/Ag could serve as efficient water purification technique, with a potential for large-scale commercialization.

In the search for sustainable alternative energy sources the dye-sensitized solar cell (DSSC) has proven a viable contender in photovoltaics with core advantages of facile and low-cost fabrication; and record cell power conversion efficiency (PCE) between 11–14%. This is competitively low; compared to that of the more common Si-based cells of 14–26%. Plasmonic DSSCs, with the potential of highly concentrating optical energy in cells from the localized surface plasmon resonance effect, were predicted to attain very high PCEs. However, the record plasmonic DSSC PCE is only 10.8%, attributed to, mainly, the secondary effects of plasmonic nanostructures not well understood yet. This study employed Ag@TiO₂ plasmonic nanowires (PNWs), a systematic approach, wide-range PNW loadings and extended characterization to study their effects on the performance of DSSCs. They enhanced PCE from 4.63% to 5.03% from a balance of the negative and positive effects of the PNWs; most uniquely via efficient charge transport. The PNWs exhibited electron-sink effect causing upward shift of the TiO₂ Fermi level with poor charge injection efficiency, at high concentrations. They improved charge collection and resistance against recombination. These results will serve as valuable guide in the field of plasmonic DSSCs and related fields.

Inorganic nano-metal oxides can be effective alternatives to drug resistant organic antibiotics due to their broad spectrum antimicrobial activity against pathogenic and mutagenic gram-negative and positive bacteria. In this study, zinc and copper oxides (ZnO and CuO) were synthesized using a facile wet chemical method. The oxide nanoparticles were characterized using X-ray diffraction (XRD), UV-Vis spectrometer (UV-Vis), Fourier Transformed Infra-red spectrometer and Transmission electron microscopy (TEM). The antibacterial activities of the nanoparticles were investigated against e. coli and s. aureus using the disk diffusion and microdilution tests. The XRD analysis revealed that both zinc and copper oxide nanoparticles were purely crystalline. The TEM micrographs showed that copper oxide nanoparticles assumed a nanorod shape of average length of 100 nm. Whiles zinc oxide nanoparticles were spherical of average diameter of 15 nm. The FTIR results showed that the nanoparticles were free of impurities and organic surfactants. The optical band gaps of CuO and ZnO according to UV-Vis analysis were respectively 2.63 eV and 3.22 eV. According to the antibacteria tests, the minimum inhibition concentration (MIC) of CuO against e. coli and s. aureus were correspondingly 1mg/ml and 0.25 mg/ml whiles it was 0.1mg/ml for ZnO against s. aureus but ZnO produced no inhibition against e. coli. With the microdilution test, both nanoparticles exhibited activity against both bacteria species at all varying concentrations. CuO had an antibacteria efficiency of 80 to 97% and 85 to 99% for e. coli and s. aureus respectively. The efficiency of ZnO were 20 to 90% and 50 to 89% for e. coli and s. aureus accordingly. The results concluded that CuO had higher antibacteria activity as compared to ZnO.