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Incorporation of reduced graphene oxide (rGO) optimizes the interfacial properties of MgMn2O4 and improves the Mg2+ diffusion in the electrode. This results in enhanced specific capacity and rate capability. MgMn2O4/rGO nanocomposites show a large discharge specific capacity of 140.1 mA h g−1 at a current density of 1000 mA g−1. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) catalyst electrode of Co3O4 nanosheets in situ formed on reduced graphene oxide modified Ni foam (Co3O4/rGO@Ni foam) for H2O2 electroreduction is prepared by a two-step hydrothermal method. In the first step, graphene oxide sheets are reduced and formed on the skeleton of Ni foam and Co3O4 nanosheets are synthesized intermixed with the rGO sheets through the second step. The Co3O4 nanosheets are made up of plentiful nanoparticles and there are many nanoholes among these nanoparticles which are beneficial for the sufficient contact between H2O2 and the catalyst. The morphology and phase composition of the Co3O4/rGO@Ni foam electrode are studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrocatalytic activity of the as-prepared electrode is investigated by cyclic voltammetry (CV) and chronoamperometry (CA). From the results, it can be seen that in 2 mol L−1 NaOH and 0.5 mol L−1 H2O2, the reduction current density of H2O2 on the Co3O4/rGO@Ni foam electrode is 450 mA cm−2 at −0.8 V which is much higher than that on Co3O4 directly supported on Ni foam. This obvious increase of the current density can be attributed to the increase of the surface area of the electrode after the addition of rGO. Also, the interpenetration of rGO and Co3O4 nanosheets improves the electron and ion transport ability of the electrode which leads to a good electrocatalytic activity and stability of the Co3O4/rGO@Ni foam electrode. [ABSTRACT FROM AUTHOR]

An effective method was proposed to prepare low dielectric constant composites based on a hybrid of graphene oxide–POSS and fluoropoly(ether ether ketone) (FPEEK). Through the formation of amide between aminopropylisobutyl polyhedral oligomeric silsesquioxane (POSS-NH2) and oxygen-containing groups (carboxyl groups) on graphene oxide (GO), the covalent functionalization of GO with POSS-NH2 (POSS-NH2–GO) hybrid was carried out, which is highly soluble in many organic solvents. The structure of the POSS-NH2–GO hybrid was confirmed by FT-IR, Raman, XRD, TGA, XPS, and TEM. The POSS-NH2–GO hybrid was well dispersed within the FPEEK polymer matrix to prepare POSS-NH2–GO/FPEEK composite films by solution blending. The dielectric constants of the composites decreased with the increasing content of POSS-NH2–GO hybrid, and a κ value of 2.01 was achieved with the incorporation of the hybrid, only 3.0 wt% could cause a 92.8% high enhancement in Young's modulus. [ABSTRACT FROM AUTHOR]