Hui-Xuan Ma

Carbon-encapsulated tungsten oxide nanowires as a stable and high-rate anode material for flexible asymmetric supercapacitors

Herein, we report an effective carbon encapsulation strategy to boost the capacitive performance of WO3−x nanowires as a high-energy and stable anode material for flexible asymmetric supercapacitors (ASCs). The carbon-encapsulated WO3−x nanowires exhibited a remarkable areal capacitance of 786.8 mF cm−2 and excellent durability. Furthermore, an ASC device with high energy and power density was also fabricated from the as-prepared carbon encapsulated WO3−x nanowire anode.

Synthesis and crystal structure of a novel Mn(II) coordination polymer with 3-(4-(1H-benzo[d]imidazol-1-yl)-4-methoxyphenyl)-1-phenylprop-2-en-1-one ligands

Abstract3-(4-(1H-Benzo[d]imidazol-1-yl)-4-methoxyphenyl)-1-phenylprop-2-en-1-one (L1, 1) and its Mn(II) complex, [Mn(L1)2(SCN)2]∞ (2), were synthesized and characterized by elemental analyses, IR spectroscopy and single-crystal X-ray diffraction. The Mn(II) ion in 2 is six-coordinated to four nitrogen atoms of two L1 ligands, two SCN-ligands, and two oxygen atoms of other two L1 ligands to form a distorted octahedral geometry. Therefore, each L1 links Mn ions through the O and N atoms to generate 2D sheet structure.

Selective Quantification of Trace Silver in Water Samples by Displacement Solidified Floating Organic Drop Microextraction Coupled With Electrothermal Atomic Absorption Spectrometry

ABSTRACT In this work, a novel displacement solidified floating organic drop microextraction (D-SFODME) technique was developed and coupled with electrothermal atomic absorption spectrometry (ETAAS) for the determination of trace silver in water samples without need of any masking agents. The method involved the formation of copper diethyldithiocarbamate (Cu–DDTC), extracted from the resultant Cu–DDTC with SFODME procedure using 1-undecanol. Then, the solidified floating organic drop was transferred into a sample solution containing silver ion, and another SFODME procedure was carried out. Trace Ag+ was selectively preconcentrated using 1-undecanol through a displacement reaction between Ag+ and the preconcentrated Cu-DDTC and the floating organic drop was diluted by ethanol for ETAAS detection. Interferences from coexisting heavy metal ions with lower stability of their DDTC complexes relative to Cu-DDTC were minimized. Under the optimal conditions, the limit of detection was 4.7 ng L−1 (3σ) for silver with a sample volume of 5.0 mL, and an enrichment factor of 250 was achieved. The relative standard deviation under optimum conditions is 3.6% (n = 7). The proposed method was successfully applied to determine trace silver in some environmental samples with satisfactory results.

Electrochemical Preparation and Characterizations of Hierarchically Polycrystalline NiPb Dendrites

Perfect polycrystalline NiPb dendrites were prepared via cathodic electrochemical deposition on Cu substrates from aqueous solution. Cyclic voltammetry was used to gain insight into the Ni/Pb codeposition mechanism. The results reveal that the dendrite consists of a long central backbone and very orderly secondary and tertiary branches. The size and shape of the dendritic structures can be tunable by changing the synthetic parameters. A formation mechanism is proposed to illustrate the growth process.

Synthesis and structural characterization of Mn(II) and Cu(II) complexes with bis(4-(1H-imidazol-1-yl)phenyl)methanone ligands

Abstract Two complexes, {Mn(hfac)2(BIPMO)}n (1), {Cu(hfac)2(BIPMO)}n (2) [hfac=1,1,1,5,5,5-hexafluoro-pentane-2,4-dionato(–), BIPMO=bis(4-(1H-imidazol-1-yl)phenyl)methanone], with the V-shaped ligands were synthesized and characterized by infrared spectroscopy, elemental analyses, along with single-crystal X-ray diffraction analyses. The X-ray diffraction studies have shown that the metal ions in 1 and 2 are both six-coordinated to two nitrogen atoms of two BIPMO ligands and four oxygen atoms of two hfac ligands to form a distorted octahedral geometry. Each BIPMO ligand acts as a bridging ligand to link two adjacent metal(II) atoms to form a helical chain in the crystal structure.

Synthesis and structural characterization of a Cu(I) complex with 4-(1H-imidazol-1-yl)phenyl)methanone ligands

A copper complex with V-shaped ligands, [(L1)Cu2Cl2]n (1), (L1 = 4-(1H-imidazol-1-yl)phenyl) methanone) has been synthesized and characterized by IR spectroscopy, elemental analyses and singlecrystal X-ray diffraction. The crystal of 1 is monoclinic, sp. gr. C2/c with the unit cell parameters a = 17.9496(13), b = 15.3440(13), c = 7.2983(7) Å, and β = 112.875(6)°, Z = 4, R1 = 0.0681, and wR2 = 0.1736 (I > 2 σ). The solid state structure of 1 consists of 2D metal aromatic chloride layers, which are propagating along the bc plane to form a 3D network through hydrogen bonds.

Crystal structure of bis[4,4,4]-trifluoro-1-(2-thienyl)butanedione-1,3] copper( II) with two 1-butylimidazole ligands, C30H32CuF6N4O4S2

Abstract C30H32CuF6N4O4S2, monoclinic, P21/n (no. 14), a = 13.209(5) Å, b = 8.715(3) Å, c = 14.599(5) Å, β = 92.217(5)°, V = 1679.3 Å3, Z = 2, Rgt(F) = 0.0509, wRref(F2) = 0.1683, T = 296 K.