ZnO nanosheets doped with yttrium（Y） were synthesized via a solution combustion method using zinc nitrate and tartaric acid as raw materials.The scanning electron microscopy and X-ray powder diffraction were used to characterize ZnO nanosheets and the gas sensing properties of them were investigated.The results show that the as-synthesized ZnO nanosheets with diameters of20-100 nm have a wurtzite structure with rough surface.The sensor made from the 2%Y-doped ZnO nanosheets exhibits a stronger response toward 100x10-6（volume fraction） ethanol,its sensitivity at 300℃ is 17.50,and its optimal operating temperature（300℃）is lower than that of the pure ZnO（330℃）.The obvious sensitivity（about 2.5） can be observed at the volume fraction of ethanol as low as 5×10-（-6）,while its the response time is only 2s at 300℃.Moreover,the Y-doped ZnO sensor has a better selectivity to ethanol than other gases.
Ce-doped ZnO microspheres were solvothermally prepared, and their microstructure, morphology, photoluminescence, and gas sensing were investigated by X-ray diffractometer, field emission scanning electron microscopy, transmission electron microscopy, fluorescence spectrometer and gas sensing analysis system. The results showed that the Ce-doped ZnO microspheres were composed of numerous nanorods with a diameter of 70 nm and a wurtzite structure. Ce-doping could cause a morphological transition from loose nanorods assembly to a tightly assembly in the microspheres. Compared with pure ZnO, the photoluminescence of the Ce-doped microspheres showed red-shifted UV emission and an enhanced blue emission. Particularly, the Ce-doped ZnO sensors exhibited much higher sensitivity and selectivity to ethanol than that of pure ZnO sensor at 320 °C. The ZnO microspheres doped with 6% Ce (mole fraction) exhibited the highest sensitivity (about 30) with rapid response (2 s) and recovery time (16 s) to 50×10?6 ethanol gas.
Using the ligand bis（3-（1H-imidazol-1-yl）-1-phenylpropan-1-one） L, two novel complexes [CuL2（ph））]·H2O 1 and [ZnL2（tp）] 2 （ph = phthalic acid, tp = terephthalic acid） have been synthesized and their crystal structures were determined by single-crystal X-ray diffraction analysis. Crystal data for 1： triclinic, space group P1^-, a = 9.4300（17）, b = 12.148（2）, c = 13.721（2） A, a = 109.620（2）,β = 94.351（2）, y = 94.830（2）°, C32H30N4O7Cu, Mr = 646.14, V= 1466.2（4） A^3, Z = 2, Dc = 1.464 g/cm3, It（MoKa） = 0.801 mm^-1, F（000） = 670, the final R = 0.0337 and wR = 0.0859 for 5122 observed reflections with I 〉 2σ（I）, And those for 2： monoclinic, space group P2/n, a = 7.1866（11）, b = 14.144（2）, c = 14.407（2）/k, β = 101.427（2）°, C32H28N4O6Zn, Mr = 629.95, V = 1435.4（4） A3, Z = 2, Dc = 1.457 g/cm3, μ（MoKa） = 0.908 mm^-1, F（000） = 652, the final R = 0.0438 and wR= 0.0821 for 2546 observed reflections with I〉 2σ（I）. In 1 and 2, ph or tp ligauds bridge the six-coordinated copper（Ⅱ） or four-coordinated zinc（Ⅱ） ions forming 1D zigzag chains while L ligands act as the terminal monodentate ligand. It is noted that weak non-classical C-H…O plays the important and dominating roles in the formation of 2D supramolecular architectures of 1, but in 2 non-classical C-H…O and aromatic π…π Stacking interactions are quite important and play dominant roles in the self-assembly of 2D supramolecular architectures.
