A series of TiO(2)-reduced graphene oxide (RGO) nanocomposites were prepared by simple one-step hydrothermal reactions using the titania precursor, TiCl(4) and graphene oxide (GO) without reducing agents. Hydrolysis of TiCl(4) and mild reduction of GO were simultaneously carried out under hydrothermal conditions. While conventional approaches mostly utilize multistep chemical methods wherein strong reducing agents, such as hydrazine, hydroquinone, and sodium borohydride are employed, our method provides the notable advantages of a single step reaction without employing toxic solvents or reducing agents, thereby providing a novel green synthetic route to produce the nanocomposites of RGO and TiO(2). The as-synthesized nanocomposites were characterized by several crystallographic, microscopic, and spectroscopic characterization methods, which enabled confrimation of the robustness of the suggested reaction scheme. Notably, X-ray diffraction and transmission electron micrograph proved that TiO(2) contained both anatase and rutile phases. In addition, the photocatalytic activities of the synthesized composites were measured for the degradation of rhodamine B dye. The catalyst also can degrade a colorless dye such as benzoic acid under visible light. The synthesized nanocomposites of biphasic TiO(2) with RGO showed enhanced catalytic activity compared to conventional TiO(2) photocatalyst, P25. The photocatalytic activity is strongly affected by the concentration of RGO in the nanocomposites, with the best photocatalytic activity observed for the composite of 2.0 wt % RGO. Since the synthesized biphasic TiO(2)-RGO nanocomposites have been shown to effectively reduce the electron-hole recombination rate, it is anticipated that they will be utilized as anode materials in lithium ion batteries.

Silver impregnated on polymer-titania nanocomposite films exhibit excellent antibacterial properties with the added advantage of repeated use. The polyethylene glycol-polyurethane-titania designated as PEG-PU-TiO 2 polymer nanocomposite films were synthesized by simple solution casting technique. Silver has been incorporated into these films by photochemical reduction of silver nitrate solution. The TiO 2 facilitated the UV photoreduction of AgNO 3 to Ag, which is active as an antibacterial agent. Fourier Transformed Infrared Spectroscopy (FT-IR) confirms the formation of the polymer, polyurethane. X-ray Diffraction (XRD) determined the structure and scanning electron microscopy (SEM), the morphology of the films. XPS confirms the Ag to be in zero oxidation state and the amount of silver impregnated in the films as estimated by scanning electron microscopy-energy-dispersive X-ray analysis (SEM-EDAX), and atomic absorption spectroscopy (AAS) is about 2-4 at %. The antibacterial properties of these films were studied on Escherichia coli and Bacillus subtilis by the disk-diffusion method and this has been correlated with the percentage of Ag in the films. One very encouraging observation is that the antibacterial activity of the Ag in polymer-titania nanocomposite films showed reasonable activity even when tested in the microbial broth.

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Exploring new single, active photocatalysts for solar-water splitting is highly desirable to expedite current research on solar-chemical energy conversion. In particular, Z-scheme-based composites (ZBCs) have attracted extensive attention due to their unique charge transfer pathway, broader redox range, and stronger redox power compared to conventional heterostructures. In the present report, we have for the first time explored CuP, a new, single photocatalyst for solar-water splitting applications. Moreover, a novel ZBC system composed of BiWO-CuP was designed employing a simple method of ball-milling complexation. The synthesized materials were examined and further investigated through various microscopic, spectroscopic, and surface area characterization methods, which have confirmed the successful hybridization between BiWO and CuP and the formation of a ZBC system that shows the ideal position of energy levels for solar-water splitting. Notably, the ZBC composed of BiWO-CuP is a mediator- and co-catalyst-free photocatalyst system. The improved photocatalytic efficiency obtained with this system compared to other ZBC systems assisted by mediators and co-catalysts establishes the critical importance of interfacial solid-solid contact and the well-balanced position of energy levels for solar-water splitting. The promising solar-water splitting under optimum composition conditions highlighted the relationship between effective charge separation and composition.