Long Lin

Carbon Nitride Decorated Ball-Flower like Co3O4 Hybrid Composite: Hydrothermal Synthesis and Ethanol Gas Sensing Application

Recently, semiconducting metal oxide (SMO) gas sensors have attracted the attention of researchers for high conductivity, labile features by environment, low cost, easy preparation, etc. However, traditional SMOs have some defects such as higher operating temperature and lower response value, which greatly limit their application in the field of gas sensor. In this work, the carbon nitride decorated ball-flower like Co3O4 composite was successfully synthesized via a facile hydrothermal method, the composition and morphology of the as-synthesized samples were studied by the techniques of X-ray powder diffraction (XRD), Field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FT-IR) and N2-sorption. As a consequence, the pure Co3O4 and the carbon nitride decorated Co3O4 both possess ball-flower like structure, and the as-synthesized carbon nitride decorated Co3O4 composite exhibits significant sensing properties to ethanol which is 1.6 times higher than that of pure Co3O4, furthermore, the composite possesses high selectivity and stability towards ethanol detection.

First-principles study on ferromagnetism in 4H-SiC codoped with Al and Mn

The electronic structures and magnetic properties in 4H-SiC codoped with Al and Mn have been investigated systematically based on density functional theory. Our results show that (Al,Mn)-codoping introduces spin-polarized hole states in 4H-SiC. The codoped system prefers the ferromagnetic state and the magnetization energy is larger than some of the known room-temperature diluted magnetic semiconductors (DMSs), indicating high RT ferromagnetism for (Al,Mn): 4H-SiC can be expected. The ferromagnetic property is mainly attributed to the 3d orbitals of Mn. Besides that the coupling of Mn–C–Mn also plays important roles in enhancing ferromagnetism in the case with more than one Mn atom. Our study explains the intrinsic factors inducing magnetism in 4H-SiC, which may provide a promising approach for preparing DMSs.

Syntheses, Crystal Structures and Fluorescence Properties of Cu(II)/Zn(II)/Ag(I) Complexes with an Amide Type Ligand

Five complexes, [CuLCl 2 ]·CH 3 COCH 3 ( 1 ), [ZnLCl 2 ]·CH 3 COCH 3 ( 2 ), [ZnL(NO 3 ) 2 ]·0.5CH 3 COCH 3 ( 3 ), [AgL 2 ]ClO 4 ( 4 ) and [AgL 2 ]BF 4 ( 5 ) (L=2-(5-chloroquinolin-8-yloxy)-1-(pyrrolidin-1-yl)ethanone), were synthesized and characterized by X-ray diffraction. Complexes 1 and 2 are isostructural, and in each of them the five-coordinated metal ion is in a distorted tetragonal pyramid with a NO 2 donor set from one ligand L and two chloride anions. However, the Zn(Ⅱ) ion in complex 3 is coordinated with one tridentate ligand L, one monodentate and one bidentate nitrate anions, giving a distorted octahedral coordination geometry. The structures of 1 ~ 3 are quite similar as those of the acetonitrile solvates derived from the same ligand L and metal salts. By contrast, the ratio of the metal ion and ligand L is 1:2 in complexes 4 and 5 , the central Ag(Ⅰ) ion in each complex is six-coordinated with two independent ligands with N 2 O donor set, thus possesses a distorted octahedral coordination geometry. In CH 3 CN solution, the emission spectra of complexes 1 , 3 , 4 and 5 exhibit similar peak at 410 nm as the ligand L. However, the emission band of complex 3 red-shifts to 430 nm because of energy transferring from the ligand L to the Zn(Ⅱ) ion. CCDC: 1484068, 1 ; 1484069, 2 ; 1484070, 3 ; 1484071, 4 ; 1484072, 5 .