Shuojue Wang

A facile synthesis of platinum nanoparticle decorated graphene by one-step γ-ray induced reduction for high rate supercapacitors

A facile method has been developed to synthesize a high-quality platinum nanoparticle (PtNP) decorated graphene via one-step γ-ray induced reduction of graphite oxide (GO) and chloroplatinic acid at room temperature. GO and Pt(IV) precursor salt could be co-reduced by the electrons generated from the radiolysis of ethylene glycol under γ-ray irradiation. The synchronous reduction of the metal precursor and regulation of pH greatly increased the ratio of C/O in the reduced GO (RGO). PtNPs with an average diameter of 1.8 nm were uniformly dispersed on the surface of RGO sheets. The as-prepared PtNP–RGO composites as supercapacitor electrodes displayed a specific capacitance of 154 F g−1 at a current density of 0.1 A g−1 and the value retained as high as 72.3% at 20 A g−1 which was significantly enhanced compared to 16.2% capacity retention of RGO prepared by the same method. The investigation of electrochemical performances suggests that PtNPs play an important role in enhancing supercapacitor performance with high rate capability by accelerating the electron transfer and increasing the electrochemical active surface area of RGO.

Efficient adsorption of 1-alkyl-3-methylimidazolium chloride ionic liquids onto modified cellulose microspheres.

A novel sulfonated cellulose microsphere adsorbent (CGS) was prepared by pre-irradiation induced emulsion grafting of glycidyl methacrylate (GMA) onto the cellulose microsphere, followed by sulfonation. The resulting CGS exhibited superior adsorption ability toward 1-alkyl-3-methylimidazolium chloride ([CnMIM]Cl) ionic liquids (ILs). The adsorption equilibrium could be attained rapidly within 40 min for representative 1-butyl-3-methylimidazolium chloride ([C4MIM]Cl) using CGS with different amounts of SO3H group. The adsorption behavior of CGS toward [C4MIM]Cl was well described by the pseudo-second-order model and the Langmuir model. The maximum adsorption capacity toward [C4MIM]Cl was 1.08 mmol/g in the wide range of pH (4.8-10.1). In addition, the adsorption capacity of CGS toward [CnMIM]Cl increased with the alkyl length of cations of [CnMIM]Cl due to the hydrophobic interaction and cation exchange adsorption. Spent CGS could be easily regenerated by 0.1 mol/L HCl or NaCl. The results indicated that this new adsorbent is useful in removing ILs from wastewater.

New lipophilic polyelectrolyte gels containing quaternary ammonium salt with superabsorbent capacity for organic solvents.

Water and soil pollution by organic pollutants from petrochemical plants has become one of the major environmental problems in recent years. Lipophilic polyelectrolyte gels with ionic groups dissociable in nonpolar organic solvents show an enhanced swelling ability in a corresponding media attributed to the electrostatic repulsion and osmotic pressure provided by dissociated ionic groups. Here, we synthesized new lipophilic polyelectrolyte gels based on an easily available electrolyte monomer, methacryloxyethyl dimethyloctane ammonium trifluoromethanesulfonimide (MODAT), and a lipophilic neutral monomer, dodecyl acrylate by radiation-induced polymerization and cross-linking. The resultant lipophilic polyelectrolyte gels could absorb plenty of organic solvents with dielectric constants lower than 20 and exhibited a high absorbing ability at a wide range of temperatures (0-40 °C). The maximum swelling degree could reach as high as 200 g/g in some media, such as 1,2-dichloroethane (199.4 g/g) and dichloromethane (204 g/g), which was much higher than that of the nonionic gel without the addition of MODAT. Moreover, the resultant lipophilic polyelectrolyte gels could release most of the absorbed solvents within several hours and then be reused. It is expected that this new type of lipophilic polyelectrolyte gels may be a suitable candidate as organic pollutant absorbents.

One-step radiation-induced construction of multi-responsive self-assemblies using simple cyclic ethers

A general and one-step method was developed as a versatile route to fabricate ‘smart’ self-assemblies via γ-irradiation of simple cyclic ethers under air atmosphere. Only by one-step irradiation in water, a series of amphiphilic oligomers containing oligo(ethylene glycol) (oligo-EG) side chains and their supramolecular assemblies with plentiful morphologies could be prepared, including flower-shaped aggregates, microsphere aggregates, well-defined core–shell micelles and nano-sized capsules. The morphology of the supramolecular assemblies could be facilely adjusted based on the different structures of the cyclic ethers. Moreover, the core–shell micelles prepared by irradiating dicyclohexano-18-crown-6 (DCH18C6) aqueous solutions could be easily controlled by simple external stimulations, such as varying temperature, pH and adding metal ions. Based on the results of a series of cyclic ethers, it is expected that this work can provide a novel and general approach to design and construct ‘smart’ supramolecular assemblies for biomedical and industrial applications.