A fluidic device for the controlled formation and real-time monitoring of soft membranes self-assembled at liquid interfaces

The work was supported by the European Research Council Starting Grant (STROFUNSCAFF) and the Marie Curie Career Integration Grant (BIOMORPH). L.B. acknowledges fnancial support from the European Community through grant no. 618335 ‘FlowMat: Flow and Capillarity in Materials Science’ and ERC Starting Grant FLEXNANOFLOW no. 715475. Te authors thank Karla E. Inostroza-Brito for the constructive support in this work

Hybrid materials of ZnO nanostructures with reduced graphene oxide and gold nanoparticles: enhanced photodegradation rates in relation to their composition and morphology

Binary and ternary hybrid systems of ZnO possessing nanoparticle and nanorod morphologies on reduced graphene oxide (rGO) and rGO with Au nanoparticles are explored as photocatalysts and a comparative study of their photodegradation performance is presented. Various preparation methods such as solution phase and hydrothermal routes have been employed to produce rGO-ZnO hybrids and rGO-Au-ZnO hybrids to impart different morphologies and defect states in ZnO. All the hybrids exhibit faster photodegradation kinetics and the rGO-Au-ZnO system exhibits the highest rate, five times faster than bare ZnO, followed by the binary systems, rGO-ZnO nanoparticles and nanorods. Various factors such as structure, morphology, charge transfer and adsorption are considered to explain the observed kinetics. Excited state electron transfer from ZnO to both rGO and Au levels facilitates faster dye degradation for rGO-Au-ZnO and is reflected as highly quenched band edge and defect state photoluminescence. Intimate physical interfaces formed between rGO, Au and ZnO in the hybrid material during in situ reactions favour charge transfer across the components. The charge transfer contribution even dominates the adsorption factor and the rGO-Au-ZnO system with a slightly lower adsorption capacity than the rGO-ZnO system exhibits a higher degradation rate. A power law dependence of the photodegradation rate on light intensity is also expressed

Films of Reduced Graphene Oxide with Metal Oxide Nanoparticles Formed at a Liquid/Liquid Interface as Reusable Surface Enhanced Raman Scattering Substrates for Dyes

Free standing, thin films of reduced graphene oxide (rGO) with ZnO, CuO and SnO2 nanostructures are prepared at a water/toluene interface utilizing simple interfacial reaction and self-assembly. rGO-ZnO, rGO-CuO and rGO-SnO2 films exhibit unique morphologies such as hexagonal cylinders, elongated splinters, and balls, respectively, wrapped by rGO layers. The hybrid films exhibit surface enhanced Raman scattering (SERS) of rhodamine 6G dye with enhancement factors one order higher than bare metal oxide caused by a synergic effect of charge transfer between the dye, metal oxide and rGO. Doping with Ag+ ions improves SERS enhancement in rGO-Ag-ZnO hybrid films, exploiting the electromagnetic effect of metal surface plasmons. Detection sensitivity up to 10 mu M dye with an enhancement factor of 104 is shown. The enhanced photodegradation rate by the hybrid films is utilized for UV induced regeneration of the used SERS substrate and is demonstrated for successive use of different analytes

Enhanced electrocatalytic activity of reduced graphene oxide-Os nanoparticle hybrid films obtained at a liquid/liquid interface

Hybrid films of reduced graphene oxideosmium nanoparticles (rGO-Os NPs) synthesized at a liquid/liquid interface are explored for their electrocatalytic activity towards the oxidation of rhodamine B (RhB), a popular colourant found in textile industry effluents and a non-permitted food colour. The freestanding nature of the films enables them to be lifted directly on to electrodes without the aid of any binders. The films consist of aggregates of ultra-small Os NPs interspersed with rGO layers. The hybrid film exhibits enhanced RhB oxidation when compared to its constituents arising from the synergic effect between rGO and Os NPs, Os contributing to electrocatalysis and rGO contributing to high surface area and conductance as well as stabilization of Os nanoparticles. The electrochemical sensor based on rGO-Os NP hybrid film on pencil graphite electrode shows a remarkable performance for the quantitative detection of RhB with a linear variation in a wide range of concentrations, 4-1300 ppb (8.3 nM-2.71 mu M). The modified electrode presents good stability over more than 6 months, reproducibility and anti-interference capability. The use of developed sensor for adequate detection of RhB in real samples such as food samples and pen markers is also demonstrated

Films and dispersions of reduced graphene oxide based Fe2O3 nanostructure composites: Synthesis, magnetic properties and electrochemical capacitance

Films and dispersions of reduced graphene oxide (rGO) composites with Fe2O3 nanostructures have been synthesized by liquid/liquid interface and co-precipitation methods, respectively. Gamma phase, Fe2O3 nanoparticles with rGO are obtained as aqueous dispersions by co-precipitation method while Fe2O3 nanostructures consisting of a mixture of alpha and gamma phases are obtained in the form of freestanding thin films at the liquid/liquid interface. Different morphologies of Fe2O3 such as nano particles and nanorods are obtained by employing a modified or bare liquid/liquid interface. The nucleation and growth in this case is controlled by the density of oxygen functional groups on rGO. A comparison of the magnetic properties of dispersion and films of nanocomposites and their constituents are presented. rGO-gamma Fe2O3 dispersions show superparamagnetic nature while films exhibit extremely low magnetic moments confirming the presence of mixed phases of Fe2O3. Electrochemical capacitance studies of nanocomposite films reveal contributions due to electrical double layer capacitance of rGO and pseudocapacitance of Fe2O3 nanostructures and a specific capacitance 64.5 Fig at 2 mV/s is estimated. These films in microgram quantities without the aid of any binders exhibit good adhesion on carbon electrodes with excellent recyclability and less internal resistance and are promising for applications as supercapacitors