Materials design and sensing mechanism of novel calix[6]arene composite for sensitively detecting amine drugs

In order to improve the co nvenie nce and sensitivity of amphetamines drug testing and reduce the threat of drugs to humans,we have designed a QCM gas sensor to detect amine-containing drugs.The sensing material is designed based on the chemical nature of amine drugs.The sensing mechanism is derived from a reve rsible Schiff base interaction between the amino group of the drug and the carbonyl group of the novel calix[6]arene derivatives as well as the hydrogen bond interaction between amino group and hydroxyl.The new composite material was well characterized by different analytical techniques including 1 H nuclear magnetic resonance(1 H-NMR),fourier transform infrared spectroscopy(FT-IR),scanning electro nic microscopy(SEM),transmission electron microscope(TEM),Raman spectra,powder X-ray diffraction,etc.The sensing experiments were conducted by coating the composite onto quartz crystal microbalance(QCM)transducers.The experimental results indicated that the novel calixarene derivatives and their GO complexes based on the design have excellent selectivity,high sensitivity and repeatability toβ-phenylethylamine.

Highly sensitive ethanol gas sensor based on ultrathin nanosheets assembled Bi_2WO_6 with composite phase

Bismuth tungstate(Bi2 WO6) has many intriguing properties and has been the focus of studies in a variety of fields, especially photocatalysis. However, its application in gas-sensing has been seldom reported.Here, we successfully synthesized assembled hierarchical Bi2 WO6 which consists of ultrathin nanosheets with crystalline-amorphous composite phase by a one-step hydrothermal method. X-ray diffraction(XRD), X-ray photoemission spectroscopy(XPS), field-emission scanning electron microscopy(FESEM),and high-resolution transmission electron microscopy(HRTEM) techniques were employed to characterize its composition, morphology, and microstructure. By taking advantage of its unique microstructure,phase composition, and large surface area, we show that the resulting Bi2 WO6 is capable of detecting ethanol gas with quick response(7 s) and recovery dynamic(14 s), extremely high sensitivity(Ra/Rg= 60.8@50 ppm ethanol) and selectivity. Additionally, it has excellent reproducibility and long-term stability(more than 50 d). The Bi2 WO6 outperform the existing Bi2 WO6-based and most of the other state-of-the-art sensing platforms. We not only provided one new member to the field of gas sensor,but also offered several strategies to reconstruct nanomaterials.

A conductive anionic Co-MOF cage with zeolite framework for supercapacitors

Conductive MOFs could exhibit full potential as integrated electrode materials for supercapacitors without interference from additional conductive additives.Here we report an anionic Co-MOF cage with zeolite framework,which was balanced by the redox-active guest [Co(H2O)6]2+ and protonated[(CH3)2NH2]2+ ions.Benefit from the unique ion skeleton structure,Co-MOF exhibits a conductivity higher than most of reported MOFs with the value of 1.42 × 10^-3 S/cm,which can be directly fabricated as electrode for supercapacitors.A maximum specific capacitance of 236.2 F/g can be achieved at a current density of 1 A/g of Co-MOF.Additionally,the electric performance and morphology of this Co-MOF can be modified by cetyltrimethylammonium bromide(CTAB) and the maximum specific capacitance could increase up to 334 F/g at 1 A/g when the ratio of ligand and CTAB is 1:6(Co-MOF-6).Furthermore,the specific capacitance can retain at 64.04% and 77.92% of the initial value after 3000 cycles of Co-MOF and Co-CTAB-6,respectively.Obviously,the addition of CTAB further improves both capacitance and cycle stability.