Graphene Oxide Hybrid with Sulfur–Nitrogen Polymer for High-Performance Pseudocapacitors

Toward the introduction of fast faradaic pseudocapacitive behavior and the increase of the specific capacitance of carbon-based electrodes, we covalently functionalized graphene oxide with a redox active thiourea-formaldehyde polymer, yielding a multifunctional hybrid system. The multiscale physical and chemical characterization of the novel 3-dimensional hybrid revealed high material porosity with high specific surface area (402 m2 g–1) and homogeneous element distribution. The presence of multiple functional groups comprising sulfur, nitrogen, and oxygen provide additional contribution of Faradaic redox reaction in supercapacity performance, leading to a high effective electrochemical pseudocapacitance. Significantly, our graphene-based 3-dimensional thiourea-formaldehyde hybrid exhibited specific capacitance as high as 400 F g–1, areal capacitance of 160 mF cm–2, and an energy density of 11.1 mWh cm–3 at scan rate of 1 mV s–1 with great capacitance retention (100%) after 5000 cycles at scan rate of 100 mV s–1

Reduced graphene oxide–silsesquioxane hybrid as a novel supercapacitor electrode

Supercapacitor energy storage devices recently garnered considerable attention due to their cost-effectiveness, eco-friendly nature, high power density, moderate energy density, and long-term cycling stability. Such figures of merit render supercapacitors unique energy sources to power portable electronic devices. Among various energy storage materials, graphene-related materials have established themselves as ideal electrodes for the development of elite supercapacitors because of their excellent electrical conductivity, high surface area, outstanding mechanical properties combined with the possibility to tailor various physical and chemical properties via chemical functionalization. Increasing the surface area is a powerful strategy to improve the performance of supercapacitors. Here, modified polyhedral oligosilsesquioxane (POSS) is used to improve the electrochemical performance of reduced graphene oxide (rGO) through the enhancement of porosity and the extension of interlayer space between the sheets allowing efficient electrolyte transport. rGO–POSS hybrids exhibited a high specific capacitance of 174 F g−1, power density reaching 2.25 W cm−3, and high energy density of 41.4 mW h cm−3 endowed by the introduction of POSS spacers. Moreover, these electrode materials display excellent durability reaching >98% retention after 5000 cycles

Graphene oxide-mesoporous SiO2 hybrid composite for fast and efficient removal of organic cationic contaminants

In this study, we have developed a novel mesoporous SiO2 - graphene oxide hybrid material (SiO2NH2-GO) as highly efficient adsorbent for removal of cationic organic dyes from water. The fabrication of such a three-dimensional (3D) SiO2NH2-GO composite has been achieved via the condensation reaction between the amine units exposed on 3-aminopropyl-functionalized silica nanoparticles and the epoxy groups on surface of GO. As a proof-of-concept, SiO2NH2-GO was used for the removal of archetypical dyes from water and revealed outstanding maximum adsorption capacity towards methylene blue (MB), rhodamine B (RhB) and methyl violet (MV) at pH 10 reaching 300, 358 and 178 mg g−1 for MB, RhB and MV, respectively, thus outperforming the neat components of composite, i.e. GO and SiO2. Moreover, the adsorption process revealed that ∼99.7% of MB, RhB and MV have been removed in only 3 min thereby highlighting the superior nature of SiO2NH2-GO composite with respect to most of graphene oxide-based adsorbents of organic dyes. Finally, the composite was used in solid phase extraction (SPE) as column packing material, for continuous water purification, thus highlighting the great potential of SiO2NH2-GO for the large-scale removal of cationic dyes from aqueous solutions