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Nanocomposite materials have demonstrated excellent performance in many application fields. Metal nanoparticle/graphene oxide composites are among the most promising composite materials for catalytic applications. In this study, nanocomposites of Au-Pd bimetallic particles/graphene oxide were prepared from an aqueous bath and used as catalysts in the oxidation reactions of some chemical compounds. The oxidation and exfoliation of graphite were controlled by varying the acid treatment time. The effects of the treatment time on the properties and performance of the prepared bimetallic-nanoparticle-supported graphene oxide catalysts were very obvious. Depending on the treatment time, a significant improvement in the conversion efficiency ranging from 65% to about 480%, along with a high oxidation selectivity, were achieved. The obtained findings show that the catalytic performance of metal/graphene oxide nanocomposites can be easily maximized by controlling the oxidation and exfoliation of graphene sheets. [ABSTRACT FROM AUTHOR]

In the current study, a comparison between the different Mn3O4/ZnO, CuO/ZnO and Fe2O3/ZnO nanocomposites with respect to their structural, morphological, optical and photocatalytic properties is presented. The nanostructure nature of the investigated composites was confirmed by the XRD and SEM analysis. The nanocrystalline ZnO, M3O4, CuO and Fe2O3 phases were observed with different crystalline structure, including hexagonal, tetragonal, monoclinic and rhombohedral, respectively. The morphology of ZnO based nanocomposites was found to be dependent on the type of the metal oxide added to ZnO nanostructure. In addition, the studied nanocomposites showed different optical properties. The highest and lowest band gap of 3.14 and 2.00 eV were obtained for ZnO nanoparticles and Fe2O3/ZnO nanocomposite. Concerning the photocatalytic properties, the ZnO nanoparticles, Mn3O4/ZnO, CuO/ZnO and Fe2O3/ZnO nanocomposites showed an efficiency of 49.63, 29.8, 11.61 and 95.34%, respectively, for the photodegradation of methylene blue. The Fe2O3/ZnO nanocomposites exhibited the highest activity for water purification compared to the other nanocomposites. [ABSTRACT FROM AUTHOR]

• GO/ZnO nanocomposites with different oxidation levels and different ZnO NPs contents were prepared. • The effect of GO oxidation level and ZnO NPs contents on the nanocomposite pollutants removal efficiency was investigated. • GO processing conditions and ZnO NPs content were found to play a major role in the nanocomposites performance. • The investigated factors can be utilized to maximize the pollutant removal ability of GO/ZnO nanocomposite. • A pollutant degradation efficiency as high as 98 % was achieved through a proper optimization of GO/ZnO nanocomposite. Nanocomposites are promising materials for many applications including environmental ones. Herein graphene oxide / zinc oxide nanocomposites were prepared using simple chemical methods and used to purify polluted water samples. Highly dispersed and uniformly decorated GO nano-sheets with ZnO nanoparticles were synthesized and were utilized for water treatment applications. Two factors were investigated: GO treatment time and ZnO NPs content in the nanocomposite and both were found to strongly affect the nanocomposite performance in degrading methylene blue. They were also found to govern the contribution of each nanocomposite constituent, GO and ZnO NPs, in pollutant removal process. Through a proper optimization of these factors, a pollutant degradation efficiency as high as 98 % was achieved. The findings show that the performance of graphene based nanocomposites for water treatment applications can be greatly enhanced by a proper control of their processing conditions and the content of each constituent of the nanocomposite. [ABSTRACT FROM AUTHOR]

We report on fully inkjet printed carbon nanotubes gas sensors on flexible substrates with improved ethanol sensing characteristics. The sensors were fabricated via two simple steps: printing the electrodes and the carbon nanotubes based - active layer. Carbon nanotubes were functionalized with carboxylic acid (COOH) and poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS). The performance analysis shows a significant enhancement in the sensitivity of the sensor with polymer wrapped nanotubes in comparison with the oxidized nanotubes, with enhancement factors greater than 2.5. Moreover, a remarkable improvement in the sensor response and recovery times after polymer functionalization is noted which bodes well for fully printable environmental sensors on flexible plastic circuits. [ABSTRACT FROM AUTHOR]