M.Z. Figueroa-Torres

Sm2FeTaO7 Photocatalyst for Degradation of Indigo Carmine Dye under Solar Light Irradiation

This paper is focused to study Sm2FeTaO7 pyrochlore-type compound as solar photocatalyst for the degradation of indigo carmine dye in aqueous solution. Sm2FeTaO7 was synthesized by using conventional solid state reaction and sol-gel method. X-ray diffraction results indicated that Sm2FeTaO7 exhibit a monoclinic crystal structure. By scanning electron microscopy analysis, it was observed that sol-gel material presents particle size of around 150 nm. The specific surface area and energy bandgap values were 12 m2 g−1 and 2.0 eV, respectively. The photocatalytic results showed that indigo carmine molecule can be degraded under solar light irradiation using the synthesized materials, sol-gel photocatalyst was 8 times more active than solid state. On the other hand, when Sm2FeTaO7 was impregnated with CuO as cocatalyst the photocatalytic activity was increased because CuO acts as electron trap decreasing electron-hole pair recombination rates.

Electroless controllable growth of ZnO films and their morphology-dependent antimicrobial properties

An electroless deposition process was used to synthesize with a controlled morphology, polycrystalline ZnO on glass substrates as antimicrobial coatings. The influence of deposition temperature (Tdep) on the physicochemical and antimicrobial properties of the ZnO films was analyzed. The results indicated that a change in deposition temperature greatly affected the morphology and the degree of crystallinity of the films. Scanning electron microscope images show that the film surface is porous at a deposition temperature of 40 and 50 °C, whereas hexagonal-plate shaped morphology predominated at 60 °C and finally at 70 and 80 °C the films consisted of rod-like particles. The films showed good transparency in the visible region. All ZnO films presented notable antimicrobial activity against the gram-negative bacteria Escherichia coli (E. coli) and the gram-positive Staphylococcus aureus (S. aureus). It was found that the antimicrobial efficiency is strongly dependent on morphology and structural properties. The best antimicrobial performance was recorded for the films consisting of rod-like morphology with a high degree of crystallinity. The procedure used in this investigation is strongly recommended for the development of functional surfaces.