Highly integrated nanocomposites of RGO/TiO2 nanotubes for enhanced removal of microbes from water.

Highly integrated nanocomposite of Graphene oxide (GO) and its derivatives with metal oxides is essential for enhanced performance for various applications. Tuning the morphology is an important aspect during nanomaterials synthesis; this has an amplifying influence upon physicochemical properties of advanced functional materials. In this research work, GO/TiO2 nanotube composites have been successfully synthesized via alkaline hydrothermal treatment method by augmenting GO layers with two different phases of TiO2 (anatase and rutile) nanoparticles, followed by the hydrothermal treatment that also have caused reduction of GO to reduced GO (RGO). The morphology of the as-prepared samples appeared to be nanotubes with a large aspect ratio (length to diameter). The synthesized materials have been characterized using various techniques to determine their morphological and functional properties. Large surface area (158 m2/g) nanotube composites found accountable as effective disinfectant for water containing microorganisms. The antimicrobial activity of the synthesized composites was examined by disk diffusion method and optical density for bacterial growth using two different bacterial species; Escherichia Coli (E.coli, Gram-negative) and Staphylococcus Aureus (Methicillin-resistant Staphylococcus aureus, Gram-positive). The antibacterial study revealed that, the anatase phase RGO/TiO2 nanotube composites manifested appreciable effect on both bacteria as compared to rutile phase RGO/TiO2 nanotubecomposite.

Nitrogen doped RGO-Co3O4 nanograin cookies: highly porous and robust catalyst for removing nitrophenol from waste water.

The fabrication of nanograins with a uniform morphology wrapped with reduced graphene oxide (RGO) in a designed manner is critical for obtaining a large surface, high porosity and efficient catalytic ability at mild conditions. Hybrid structures of metal oxides decorated on two-dimensional (2D) RGO lacked an interface and channels between the individual grains and RGO. The present work focuses on the synthesis of RGO-wrapped Co3O4 nanograin architecture in micron-sized polyhedrons and the ability to reduce aromatic nitro compounds. Doping N in the designed microstructure polyhedrons resulted in very large surface area (1085.6 m2 g-1) and pore density (0.47 m3 g-1) microcages. Binding energies from x-ray photoelectron spectroscopy (XPS) and Raman intensities confirmed the presence of doped N and RGO-wrapped around Co3O4 nanograins. However, the morphology and microstructure was supported by FESEM and HRTEM images revealing the fabrication of high integrity RGO-Co3O4 microstructure hybrids composed of a 10 nm grain size with narrower grain size distribution. Ammonia treatment produced interconnected channels and dumbbell pores that facilitated ion exchange between the catalyst surface and the liquid medium at the grain boundary interfaces, and offered less mass transport resistance providing fast adsorption of reactants and desorption of the product causing surface renewal. Prepared N-RGO-Co3O4 shows the largest percentage reduction (96%) of p-nitrophenol (p-NP) at room temperature as compared to pure Co3O4 and RGO-Co3O4 nanograin microstructures over 10 min. Fabricated architectures can be applied effectively for fast and facile treatment of industrial waste streams with complex organic molecules.