Graphite oxide is obtained by treating graphite with strong oxidizers. The bulk material disperses in basic solutions yielding graphene oxide. Starting from exfoliated graphite, different treatments were tested to obtain the best graphite oxide conditions, including calcination for two hours at 700°C and ultrasonic agitation in acidic, basic, or peroxide solutions. Bulk particles floating in the solution were filtered, rinsed, and dried. The graphene oxide obtained was characterized under SEM and FTIR techniques. On the other hand, nylon 6-6 has excellent mechanical resistance due to the mutual attraction of its long chains. To take advantage of the properties of both materials, they were combined as a hybrid material. Electrochemical cells were prepared using porous silica as supporting electrode of the electrospun nylon/graphene oxide films for electrochemical testing. Polarization curves were performed to determine the oxidation/reduction potentials under different acidic, alkaline, and peroxide solutions. The oxidation condition was obtained in KOH and the reduction in H₂SO₄solutions. Potentiostatic oxidation and reduction curves were applied to further oxidize carbon species and then reduced them, forming the nylon 6-6/functionalized graphene oxide composite coating. Electrochemical impedance measurements were performed to evaluate the coating electrochemical resistance and compared to the silica or nylon samples.

In this work, we present the results of two synthesis approaches for mesoporous magnesium carbonates, that result in mineralization of carbon dioxide, producing carbonate materials without the use of cosolvents, which makes them more environmentally friendly. In one of our synthesis methods, we found that we could obtain nonequilibrium crystal structures, with acicular crystals branching bidirectionally from a denser core. Both Raman spectroscopy and X-ray diffraction showed these crystals to be a mixture of sulfate and hydrated carbonates. We attribute the nonequilibrium morphology to coprecipitation of two salts and short synthesis time (25 min). Other aqueous synthesis conditions produced mixtures of carbonates with different morphologies, which changed depending on drying temperature (40 or 100 °C). In addition to aqueous solution, we used supercritical carbon dioxide for synthesis, producing a hydrated magnesium carbonate, with a nesquehonite structure, according to X-ray diffraction. This second material has smaller pores (1.01 nm) and high surface area. Due to their high surface area, these materials could be used for adsorbents and capillary transport, in addition to their potential use for carbon capture and sequestration.

In this work, synthesis and characterization of reduced graphene oxide/polyaniline/Au nanoparticles (GO/PANI/NpAu) as a hybrid capacitor are presented. Graphite oxide (GO) was synthesized by a modified Hummer’s method. Polyaniline was synthesized by chemical polymerization, and Au nanoparticles (NpAu) were added afterward. Fabrication of the electrodes consisted on the hybrid materials being deposited on carbon cloth electrodes. The chemical and structural properties of the electrode were characterized by high-resolution scanning electron microscopy (HRSEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-R), and Raman spectroscopy; the results confirm the graphene reduction, the covalent functionalization, and formation of nanocomposites and also show the polyaniline grafted graphene. The performance and evaluation of the electrodes based on grapheme oxide (GO), polyaniline (PANI), GO-PANI, and GO/PANI/NpAu nanocomposites over carbon cloth, stainless steel, and copper have been obtained in 1 M H2SO4 solution, using electrochemical techniques namely: cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). They showed that GO/PANI/NpAu gave higher specific capacitance (SC) and energy values than PANI, and GO/PANI, in the order of 160 F/g. The present study introduces new hybrid material for energy applications, from the evaluation of their electrical contributions.