No abstract

A facile method has been developed to synthesize a high-quality platinum nanoparticle (PtNP) decorated graphene via one-step g-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 g-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 À1 at a current density of 0.1 A g À1 and the value retained as high as 72.3% at 20 A g À1 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.

The application of room-temperature ionic liquids (RTILs) in nuclear spent fuel recycling requires a comprehensive knowledge of radiation effects on RTILs. Although preliminary studies indicate a relatively high radiation stability of RTILs, little attention is paid to the color change of RTILs, an obvious phenomenon of RTILs during irradiation. In this paper, we have investigated radiation-induced darkening and decoloration of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIm][NTf2]), an ionic liquid representing the most popular class of RTILs, by means of UV-Vis analysis and time-dependent density functional theory calculations. Based on the experimental and computational results, it is proposed that the color change of [BMIm][NTf2] upon irradiation originates from the formation of double bonds in the aliphatic chains of pristine organic cations (or radiolytic products of RTILs) and various associated species containing these "double-bond products". This work sheds light on the understanding of the radiation-induced color change of RTILs.