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We report on the selective and sensitive colorimetric detection of Ag+ in a dimethylformamide (DMF) solution in the presence of graphene oxide based on the surface plasmon resonance absorption of Ag nanoparticles (NPs).

A novel ratiometric fluorescent probe BCB was reported for the first time for the sensitive and selective analysis of Ag based on two Boradiazaindacene (BODIPY) as both the reference fluorophore and recognition part. Upon the addition of Ag ions, a strong fluorescence emission at 570 nm from recognition BODIPY would be appeared, whereas the fluorescence of the other BODIPY at 535 nm would be a constant reference fluorescence signal. As a result, the ratio of fluorescence intensity (λ570/λ535) was changed from 0.16 to 1.0. And the selectivity of BCB towards Ag over other metal ion was excellent. Other metal ions, such as Cd, Cu, Fe, Hg, Mg, Ni, Pb and Zn showed negligible changes in the both absorption and fluorescence spectra of BCB.

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The dangers of organic dye pollutants and environmental pollution improvement through photocatalytic degradation are important courses in applied chemistry programs in universities. Zinc oxide (ZnO)-based nanomaterials are potent catalytic agents against organic dyes, but few experiments are available for students to understand their role and mechanism in class. Herein, we designed a comprehensive experiment across 24 class hours for undergraduates to investigate the photodegradation of colored organic dyes, including methylene blue, methyl orange, methyl violet, rhodamine B, basic fuchsin, and thymolphthalein, by a nanocomposite composed of ZnO-coated graphene oxide (ZnO/GO). This nanomaterial was prepared using a facile heating reflux method within 1 h. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction were introduced to students to characterize the synthesized products. Students could observe the time- and dose-dependent degradation as well as the reusability of ZnO/GO. Additionally, the addition of t-butanol, benzoquinone, and triethanolamine, scavengers of hydroxyl radical (•OH), superoxide anion (•O2–), and hole (h+), respectively, to the degradation system allowed them to master the underlying catalytic mechanism of ZnO/GO. This experiment improves students’ understanding of the photocatalytic effect of ZnO nanomaterials and stimulates them to engage in the field of applied chemistry and thus is worth recommending to undergraduates.

La 2 O 3 /graphene oxide (GO) nanocomposites were simply synthesized from commercially available LaCl 3 ⋅7H 2 O and multilayer GO (5-10 layers) in N,N-dimethylformamide (DMF) under reflux condition without extra stabilizer. The characterization results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS) spectroscopies showed that the crystalline La 2 O 3 nanoparticles were successfully attached on the surface of GO. Moreover, the as-prepared nanocomposites greatly enhanced the degradation efficiency of organic dyes after 15 min under ultrasound irradiation in pure water. The degradation efficiency of the nanocomposites for methylene blue could be over 99%.

In this paper, a high selective fluorescent sensor for nickel ion based on borondipyrromethene (BODIPY) has been studied. Upon addition of Ni(II) ion, the fluorescence of sensor (compound 1) would be quenched, and the selectivity towards Ni(II) ion over Ag(I), Cd(II), Cu(II), Fe(III), Hg(II), Pb(II), and Zn(II) is good in acetonitrile, there is almost no interference from other heavy metal ions. The stoichiometry of complexation for compound 1 with Ni(II) ion is 1:1, and the quenching process could be reversed by triethanolamine. KEYWORDS

A graphene oxide-(GO-) boradiazaindacenes (BODIPY) charge-transfer complex (BGO) has been easily synthesized, and the structure of BGO was confirmed by FT-IR and atomic force microscopy (AFM). Moreover, the BGO was found that could be used as a turn-on fluorescent sensor for Hg 2+ . Upon addition of Hg 2+ , the fluorescence of BGO would be enhanced since the energy transfer between BODIPY and GO was inhibited. The selectivity and the competition performance of BGO towards Hg 2+ were good among other heavy metal ions.