Ge Tian

A chiral layered Co(II) coordination polymer with helical chains from achiral materials

A layered coordination polymer Co(PDC)(H2O)2.H2O containing two helical chains was synthesized, and the resultant crystals were not racemic as evidenced by the observation of strong signals in vibrational circular dichroism (VCD) spectra.

Triethylammonium benzene-1,3,5-tricarboxylato(pyridine)zinc(II): a two-dimensional undulating mesh network

Abstract A two-dimensional layered metal-organic framework material (HN(CH2CH3)3)Zn(BTC)(Pyd) with chiral trigonal pores has been prepared with HTEA+ as the structure-directing agent under mild synthetic condition. Crystal data for (HTEA)Zn(BTC)(Pyd): M=450.77, Orthorhombic, space group Pbca, a=13.652(4) A, b=16.345(4) A, c=18.734(6) A, V=4180(2) A 3 , T=293 K, Z=8, μ=1.213 mm −1 , D c =1.439 mg/m 3 . 9197 reflections measured, 2972 observed (Rint=0.0905), which were used in all calculations. The final R1=0.0498, Rω=0.1134. The structure was solved by direct methods using SHEUXTU-97.

Reduced graphene oxide modified mesoporous FeNi alloy/carbon microspheres for enhanced broadband electromagnetic wave absorbers

Absorbers have been investigated widely so as to eliminate or at least significantly attenuate the hazards of electromagnetic radiation. A porous structure is believed to be beneficial for the high-performance of microwave absorption. Here, an embedded magnetic mesoporous composite (FeNi alloyed porous carbon microspheres, FeNi/CS) is for the first time evaluated as a microwave absorbing material. Upon combining reduced graphene oxide (rGO) with the FeNi/CS composite, a multiple-component absorber of FeNi/CS/rGO is synthesized via hydrothermal and freeze-drying processes. Compared to unmodified FeNi/CS, the FeNi/CS/rGO composite provides an effective component and a more specific structure, which is favorable for translating microwave into thermal energy or other forms of energy. The minimum reflection loss (RL) value of the FeNi/CS/rGO composite reaches −45.2 dB at a thickness of 1.5 mm, and the maximum effective microwave absorption bandwidth (RL < −10 dB) is up to 5.0 GHz at d = 1.5 mm. In virtue of the dielectric loss, magnetic loss, unique heterostructure of the absorber, and impedance matching, the FeNi/CS/rGO composite exhibits overwhelming advantages of low density, small thickness, broad bandwidth, strong absorption and high anti-oxidation capability.

Facile synthesis of mesoporous FeNi-alloyed carbonaceous microspheres as recyclable magnetic adsorbents for trichloroethylene removal

Magnetic mesoporous FeNi/CS composites (FeNi alloy embedded in a porous carbon sphere) have been synthesized via a facile one-pot hydrothermal carbonization method, using metal nitrates and glucose as magnetic particle precursors and the carbon source, respectively. The properties of FeNi/CS were characterized with X-ray diffraction (XRD), Raman spectroscopy, a scanning electron microscopy (SEM) system, transmission electron microscopy (TEM), thermo-gravimetric analysis (TGA), nitrogen adsorption/desorption isotherms and a magnetic property measurement system (SQUID-VSM). FeNi/CS derived at different pyrolysis temperatures of 500, 700, 900 °C (FeNi/CS-500, FeNi/CS-700, FeNi/CS-900, respectively) could serve as novel magnetic carbonaceous adsorbents for removing trichloroethylene from aqueous media. FeNi/CS produced at 700 °C has the best removal capacity among all, mainly due to its large surface area, a wider range of pore size distribution, and suitable carbonized extent. The pseudo-second order model is well fitted to the kinetic data, indicating that chemisorption is the primary mechanism of TCE adsorption onto FeNi/CS. Moreover, the obtained magnetic porous composites could be easily separated from solution by using a permanent magnet after adsorbing TCE and used as efficient and recyclable adsorbents in the successive removal of TCE from wastewater.

Economical synthesis of composites of FeNi alloy nanoparticles evenly dispersed in two-dimensional reduced graphene oxide as thin and effective electromagnetic wave absorbers

Developing electromagnetic wave absorbing materials prepared by a facile and economical way is a great challenge. Herein, we report a feasible route to synthesize a series of two-dimensional FeNi/rGO composites by a hydrothermal method followed by a carbonization process. The characterization confirms that nano-sized FeNi alloy nanoparticles are evenly supported onto graphene sheets without aggregation. The homogeneous dispersion of the nanoparticles may result from the introduction of glucose and the oxygen-containing groups on the surface of the graphene oxide. Measurements show that the microwave attenuation capability of the composites can be improved dramatically by adjusting the proportion of dielectric and magnetic components. Consequently, the two-dimensional magnetic material (FeNi/rGO-100) exhibits an excellent microwave absorption performance. In detail, the minimum reflection loss of −42.6 dB and effective bandwidth of 4.0 GHz can be reached with a thinner thickness of 1.5 mm. This study demonstrates that synergistic effects among the magnetic particles, reduced graphene oxide and amorphous carbon layers give rise to the highlighted microwave attenuation ability. Overall, the FeNi/rGO composite is a promising candidate to be used as a microwave absorber, and the feasible and economical method has shown potential application to construct multitudinous two-dimensional materials.

One-step synthesis of 5-ethyl-2-methylpyridine from NH4HCO3 and C2H5OH under hydrothermal condition

A simple one-pot approach to synthesizing 5-ethyl-2-methylpyridine(EMP) was established using NH4HCO3 and C2H5OH as starting materials and commercial Cu2O as catalyst and oxidant under hydrothermal condition. Different reaction conditions were researched and the optimal ones were achieved by studying the parameters, that could affect the yield of product and by considering the energy and resource saving. The present study provided an eco-friendly way to obtaining EMP with lower volatility using fewer toxic starting materials.