Preparation of bismuth vanadate and cerium dioxide (BiVO4/CeO2) nanocomposites as visible-light photocatalysts was successfully obtained by coupling a homogeneous precipitation method with hydrothermal techniques. The BiVO4/CeO2 nanocomposites with different mole ratios were synthesized and characterized by X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). Absorption range and band gap energy, which are responsible for the observed photocatalyst behavior, were investigated by UV-vis diffuse reflectance (UV-vis DR) spectroscopy. Photocatalytic activities of the prepared samples were examined by studying the degradation of model dyes Methylene Blue, Methyl Orange, and a mixture of Methylene Blue and Methyl Orange solutions under visible-light irradiation (>400 nm). Results clearly show that the BiVO4/CeO2 nanocomposite in a 0.6:0.4 mol ratio exhibited the highest photocatalytic activity in dye wastewater treatment.

(2013). Manganosite-microwave exfoliated graphene oxide composites for asymmetric supercapacitor device applications. Electrochimica Acta, 101 99-108.Manganosite-microwave exfoliated graphene oxide composites for asymmetric supercapacitor device applications AbstractGraphene based materials coupled with transition metal oxides are promising electrode materials in asymmetric supercapacitors owing to their unique properties which include high surface area, good chemical stability, electrical conductivity, abundance, and lower cost profile over time. In this paper a composite material consisting of graphene oxide exfoliated with microwave radiation (mw rGO), and manganosite (MnO) is synthesised in order to explore their potential as an electrode material. The composite material was characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to explore the process occurring at the electrode/electrolyte interface. Long term cyclability and stability were investigated using galvanostatic charge/discharge testing. From the resulting analysis, an asymmetric supercapacitor was constructed with the best composite containing 90% MnO-10% mw rGO (w/w). The device exhibited a capacitance of 0.11 F/cm2 (51.5 F/g by mass) and excellent capacity retention of 82% after 15,000 cycles at a current density of 0.5 A/g. Keywords exfoliated, applications, microwave, device, graphene, supercapacitor, asymmetric, composites, oxide, manganosite Disciplines Engineering | Physical Sciences and Mathematics Publication DetailsAntiohos, D., Pingmuang, K., Romano, M. S., Beirne, S., Romeo, T., Aitchison, P., Minett, A., Wallace, G., Phanichphant, S. & Chen, J. (2013 AbstractGraphene based materials coupled with transition metal oxides are promising electrode materials in asymmetric supercapacitors owing to their unique properties which include high surface area, good chemical stability, electrical conductivity, abundance, and lower cost profile over time. In this paper a composite material consisting of graphene oxide exfoliated with microwave radiation (mw rGO), and manganosite (MnO) is synthesised in order to explore their potential as an electrode material. The composite material was characterised by scanning electron microscopy (SEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) was used to explore the process occurring at the electrode / electrolyte interface. Long term cyclability and stability was investigated using galvanostatic 2 charge / discharge testing. From the resulting analysis, an asymmetric supercapacitor was constructed with the best composite containing 90% MnO-10% mw rGO (w/w). The device exhibited a capacitance of 0.11 F/cm 2 (51.5 F/g by mass) and excellent capacity retention of 82% after 15 000 cycles at a current density of 0.5 A/g.

The creation of composite structures is a commonly employed approach towards enhanced photocatalytic performance, with one of the key rationales for doing this being to separate photoexcited charges, affording them longer lifetimes in which to react with adsorbed species. Here we examine three composite photocatalysts using either WO3, TiO2 or CeO2 with BiVO4 for the degradation of model dyes Methylene Blue and Rhodamine B. Each of these materials (WO3, TiO2 or CeO2) has a different band edge energy offset with respect to BiVO4, allowing for a systematic comparison of these different arrangements. It is seen that while these offsets can afford beneficial charge transfer (CT) processes, they can also result in the deactivation of certain reactions. We also observed the importance of localized dye concentrations, resulting from a strong affinity between it and the surface, in attaining high overall photocatalytic performance, a factor not often acknowledged. It is hoped in the future that these observations will assist in the judicious selection of semiconductors for use as composite photocatalysts.