Building up Graphene-Based Conductive Polymer Composite Thin Films Using Reduced Graphene Oxide Prepared by γ

In this paper, reduced graphene oxide (RGO) was prepared by means of γ-ray irradiation of graphene oxide (GO) in a water/ethanol mix solution, and we investigated the influence of reaction parameters, including ethanol concentration, absorbed dose, and dose rate during the irradiation. Due to the good dispersibility of the RGO in the mix solution, we built up flexible and conductive composite films based on the RGO and polymeric matrix through facile vacuum filtration and polymer coating. The electrical and optical properties of the obtained composite films were tested, showing good electrical conductivity with visible transmittance but strong ultraviolet absorbance

Engineering PtRu bimetallic nanoparticles with adjustable alloying degree for methanol electrooxidation: enhanced catalytic performance

Abstract(#br)PtRu bimetal is of particularly attractive in various electrocatalytic reactions owing to its synergistic effect, ligand effect and strain effect. Here, PtRu nanoalloy supported on porous graphitic carbon (PC) has been successfully prepared via a very facile method involving co-reduction the precursors of Pt and Ru at 300 °C by H 2 (PtRu/PCL) followed by thermal treatment at high temperature (700 °C, PtRu/PC–H). Specifically, the electrocatalytic performance of PtRu/PC nanoalloy could be dramatically enhanced through high-temperature annealing. This strategy has synthesized smaller Pt and PtRu nanoparticles (ca. L and Pt/PC nanocatalysts. The mass activity and specific activity on PtRu/PC–H nanoalloy can be increased to 1674.2 mA mg −1 Pt and 4.4 mA cm −2 for MOR, it is 4.08 and 8.80 times higher than that of the Pt/PC nanocatalyst, respectively. From in-situ FTIR spectra, we can discover PtRu/PC–H nanoalloy generates CO 2 at a lower potential of −150 mV than those on PtRu/PC–L (0 mV) and Pt/PC (50 mV) nanocatalysts, dramatically improves the ability of cleavage C–H bond and alleviates the CO ads poisoning on active sites. The PtRu/PCH nanocatalyst exhibits maximum power density of 83.7 mW cm −2 in single methanol fuel cell test, which more than threefold than that of commercial Pt/C as the anode catalyst. Those experimental results open an effective and clean avenue in the development and preparation of high-performance Pt-based nanocatalysts for direct methanol fuel cells

Development of miniature mass spectrometry system for therapeutic drug monitoring

A bench-top miniature mass spectrometry system, Mini 12, with a rectilinear ion trap mass analyzer has been developed and characterized in this thesis work. The ion processing system, vacuum system, and control system were designed. An integrated sample loading system facilitates the automated operation. A user interface has been developed to acquire and to display analytical results for personnel who have limited mass spectrometry knowledge. Peak widths of 0.6 Thomson (full width at half maximum) and mass range of up to m/z 900 were both demonstrated. Multi-stage MS experiments up to MS5 were accomplished. Consumable cartridges have been designed for use with ambient paper spray ionization and the recently developed extraction spray ionization method has been employed to improve the quantitation performance. Detecting trace-level therapeutic drugs, monitoring food safety, and environmental protection, were demonstrated. MS/MS scan capabilities were implemented for obtaining the intensities of the fragment ions from the analyte and its internal standard, of which the ratio was used in quantitative analysis of complex samples. Limits of quantitation (LOQ) of 7.5 ng/mL with relative standard deviations below 10% have been achieved for selected therapeutic drugs in whole blood throughout their therapeutic ranges. By way of developing 3D arrays of large numbers of ion traps but with simple configurations, the concept of ion sponge has also been explored in this thesis work. An ion sponge device with 484 trapping units in a volume of 10 × 10 × 3.2 cm has been constructed by simply stacking 9 meshes together. A single rf was used for trapping ions and mass-selective ion processing. The ion sponge provides a large trapping capacity and is highly transparent for transfer of ions, neutrals, and photons for gas phase ion processing. Multiple layers of quadrupole ion traps, with 121 trapping units in each layer, can operate as a single device for MS or MS/MS analysis, or as a series of mass-selective trapping devices with interlayer ion transfers facilitated by AC and DC voltages. Automatic sorting of ions to different trapping layers based on their mass-to-charge (m/z) ratios was achieved with traps of different sizes. Tandem in-space MS/MS has also been demonstrated with precursor ions and fragment ions trapped in separate locations. Tandem mass spectrometry (MS/MS) is an essential tool in complex mixture analysis, due to its capability of elucidating chemical structures, suppressing chemical noises, and achieving quantitation at high precisions. The typical MS/MS analysis has been done by isolating the target precursor ions, while wasting other ions, followed by a fragmentation that produces the product ions. In this thesis, configurations of dual linear ion traps were explored to develop high efficiency MS/MS analysis. The ions trapped in the first linear ion trap were axially, mass-selectively transferred to the second linear ion trap for MS/MS analysis. Ions from multiple compounds simultaneously introduced into the mass spectrometer could be sequentially analyzed. This development enables a highly efficient use of sample and also significantly improves the analysis speed and the quantitation precision for the ion trap mass spectrometers with discontinuous atmospheric pressure interfaces, especially for the miniature systems with ambient ionization sources. (Abstract shortened by UMI.

Electron beam radiation stability of metal-organic frameworks

In this study, four typical metal-organic frameworks (MOFs), (MIL-101 (Cr), ZIF-8, UiO-66, and UiO-66-NH2) were irradiated using electron beam radiation under different atmospheres (air, nitrogen), and dispersion liquids (water, methanol, and ethanol). The chemical composition, crystal structure, and surface morphology of MOFs before and after irradiation were characterized by Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and scanning electron microscopy. The results showed that the corresponding infrared characteristic peaks, diffraction peaks, and surface morphology characteristics of all four MOFs did not change significantly after irradiation at the dose of 5 000 kGy, showing good radiation stability. This provides the basis for further application of MOFs in a radiation environment

Radiation preparation of polyvinyl alcohol (PVA)-modified polyethylene glycol terephthalate (PET) films and their anti-fogging properties

In this study, polyvinyl alcohol (PVA)-modified polyethylene glycol terephthalate (PET) films were prepared using γ-radiation crosslinking. The PVA molecules formed a crosslinking network after γ-irradiation and were loaded onto the surfaces of the PET films. The samples were analyzed by Fourier-transform infrared spectroscopy and scanning electron microscopy to demonstrate that the PVA was successfully anchored to the PET film surfaces. Light transmission tests revealed that the modified films maintained good optical properties with a light transmission of 89%. Whether under high-temperature, high-humidity, or low-temperature freezing conditions, the tests revealed that the samples exhibited good anti-fogging performance. Saturated water absorption tests revealed that the anti-fogging properties of the modified PET films were derived from the water absorption of the PVA crosslinking network, where the PET film under 12.43% loading showed a saturated water absorption of 50%