PhD student, The University of Adelaide
An easy method to synthesize graphene/α-MnO2 nanowires composite with 3D porous structure, for batteries and energy storage devices with outstanding performance.
Abstract: Green fluorescent onion-like carbon nanoparticles were synthesized via traditional pyrolysis of flaxseed oil for photocatalytic and sensing applications.Onion-like carbon nanoparticles (CNOs) were synthesized via traditional pyrolysis of flaxseed oil. Oxidative treatment of as-synthesized carbon soot introduced numerous carboxyl (−COOH) functionalities, rendering them hydrophilic and stable in aqueous phase. The water-soluble onion-like carbon nanoparticles (wsCNOs) were 4–8 nm in size and exhibited stable green photoluminescence (PL) emission. CNOs were explored as efficient photocatalysts for the degradation of methylene blue (MB) as model organic pollutant dye under visible light irradiation. The wsCNOs exhibited photocatalytic efficiency ∼9 times higher than CNOs for MB degradation. Enhanced photocatalytic efficiency of wsCNOs was attributed to their surface functionalities and nanostructure. The unique morphology (concentric nanographene shells) with considerable surface defects, increased the physisorption of MB on the wsCNOs surface and significantly enhanced the photocatalytic efficiency of wsCNOs. Furthermore, the wsCNOs enabled specific detection of Al(III), even with interference from high concentrations of other metal ions, with a detection limit of 0.77 μM, which compares favorably to other reported fluorescent probe. Altogether, the wsCNOs showed a significantly enhanced photocatalytic activity and were used as highly selective fluorescent probes for Al(III) ion detection, suggesting a potential use in environmental wastewater treatment.
Pub.: 30 Mar '17, Pinned: 02 Aug '17
Abstract: We present a facile hydrothermal method to produce graphene-metal oxide composite that offer synergistic effect of three-dimensional (3D) graphene and electroactive α-MnO2 nanowires to improve high energy storage capability in supercapacitors. The graphene/α-MnO2 nanowire hydrogel is prepared via a simple hydrothermal route, in which graphene and α-MnO2 nanowires are self-assembled into 3D macroporous network structures. An asymmetric supercapacitor device is fabricated by using graphene/α-MnO2 nanowire hydrogel as positive electrode and 3D graphene hydrogel as negative electrode in an aqueous Na2SO4 electrolyte. The asymmetric cell can be cycled in the wide voltage range of 0–2 V and exhibit a gravimetric energy density of 38 Wh kg−1 with a maximum power density of 258 kW kg−1. In addition, it shows a good cycle stability with ∼94% capacitance retention after 1000 cycles. The graphene/α-MnO2 nanowires hybrid hydrogels may have great potential in developing energy storage devices with high energy and power densities.
Pub.: 12 Apr '17, Pinned: 02 Aug '17