Tingting Gao

Fabrication of vesicular polyaniline using hard templates and composites with graphene for supercapacitor

Vesicular polyaniline (VPANI) has been fabricated for the first time via a facile two-step method, which uses high-quality multilamellar vesicular SiO2 as hard templates. The graphene-wrapped VPANI (VPANI@RGO) composites were prepared by self-assembling graphene oxide onto VPANI and subsequently conducting the hydrothermal reduction process. The morphological characterization of the composites confirms the uniform wrapping of the graphene sheets on the VPANI. The structural characterization of the composites reveals a strong π–π electron and hydrogen bond interaction in the composites. The VPANI@RGO composites exhibit an excellent supercapacitor performance with an enhanced specific capacitance (573xa0Fxa0g−1) and a good cycling stability, which maintains its capacity of up to 85.7xa0% over 1000xa0cycles at 1xa0Axa0g−1.

Controllable morphology transition from vesicular to worm-like to vesicular multilamellar mesoporous silica induced by β-cyclodextrin

Changes in the morphology of mesoporous silica from vesicular to worm-like to vesicular multilamellar were controlled by adding appropriate amounts of β-cyclodextrin to mixed cetyltrimethylammonium bromide/didodecyldimethylammonium bromide surfactant aggregates.

Facile preparation of hybrid porous polyanilines for highly efficient Cr(VI) removal

In the present work, leucoemeraldine-based hybrid porous polyanilines (LHPPs) have been synthesized by the Friedel–Crafts reaction of leucoemeraldine and octavinylsilsesquioxane (OVS) for Cr(VI) removal. The resulting LHPPs were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and N2 adsorption–desorption. The findings indiated that the LHPPs were amorphous, with apparent surface areas (SBET) in the range of 147 to 388 m2 g−1 and total volumes in the range of 0.13 to 0.44 cm3 g−1. Cr(VI) removal experiments displayed that the LHPPs exhibited highly efficient Cr(VI) removal performance. The maximum Cr(VI) removal capacity of LHPP-1 was 990.1 mg g−1 at 308 K and pH 1, which is higher than those of other reported polyaniline-based adsorbents. The adsorption process was a spontaneous, endothermic and chemical adsorption process. The adsorption behavior agreed well with Langmuir models and pseudo second-order equations. X-ray photoelectron spectroscopy and Fourier transformed infrared (FTIR) spectroscopy analysis revealed that the highly efficient Cr(VI) removal performance can be mainly attributed to the existence of numerous amine and imine groups on the surface of the LHPPs; these can function as adsorption active sites for Cr(VI) removal through electrostatic adsorption and reduction to Cr(III) under acidic conditions. Moreover, the LHPPs exhibited excellent adsorption selectivity for Cr(VI) despite the presence of other metal ions (K+, Cu2+, Mn2+) and anions (NO3−, SO42−). Therefore, the LHPPs have potential applications for Cr(VI) removal in industrial wastewater.

Fabrication of biosensor based on core–shell and large void structured magnetic mesoporous microspheres immobilized with laccase for dopamine detection

The Fe3O4@SiO2@vmSiO2 microspheres with ordered mesochannels and large inter-lamellar void were successfully prepared through stepwise solution-phase interface deposition. Fe3O4 nanoparticles were coated with SiO2 via the Stöber method, and they were further coated with mesoporous SiO2 using aggregation of cetyltrimethylammonium chloride as template to prepare Fe3O4@SiO2@vmSiO2. The Fe3O4@SiO2@vmSiO2 microspheres show a well-defined core–shell structure with high magnetization (~xa030.9xa0emuxa0g−1), ordered mesochannel (~xa06.8xa0nm in diameter), and inter-lamellar void (~xa030xa0nm). Laccase (LAC) was immobilized on a modified Fe3O4@SiO2@vmSiO2 microsphere by covalent attachment and stabilized onto the glassy carbon electrode (GCE) surface (Fe3O4@SiO2@vmSiO2-LAC/GCE) in the fabrication of novel immobilized LAC biosensors for monitoring dopamine (DA). The electrochemical properties of the biosensor were investigated with electrochemical impedance spectroscopy and cyclic voltammetry. The immobilized LAC biosensor possesses good DA electrocatalytic activity with a linear range of 1.5–75xa0μmolxa0L−1 and low detection limit of 0.177xa0μmolxa0L−1 and shows strong anti-interference ability and excellent selective determination of DA that coexists with ascorbic acid. The immobilized LAC biosensor was also used to detect DA in pharmaceutical injection. The recoveries of 98.7–100.5% were obtained for the samples, which illustrate great potential for practical application.