Stable binary single source precursors （SSP） for the deposition of thin films of ceramic semiconductors of composition SnO·GeO were synthesized by close circuit chemical vapour deposition （CCCVD） method. Elem...Stable binary single source precursors （SSP） for the deposition of thin films of ceramic semiconductors of composition SnO·GeO were synthesized by close circuit chemical vapour deposition （CCCVD） method. Elemental analysis and spectroscopic techniques were used to characterize the precursors. Scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS） were employed to characterize the thin films. Resistivity measurements were conducted to show that the films are of semiconducting nature.展开更多
Single source molecular precursors （SSPs） provide an opportunity to get control over the microstructure of nanomaterials at atomic level. A SSP was designed and developed for the synthesis of ZnO/TiO2 nanocomposite ...Single source molecular precursors （SSPs） provide an opportunity to get control over the microstructure of nanomaterials at atomic level. A SSP was designed and developed for the synthesis of ZnO/TiO2 nanocomposite by sol gel method. In a typical synthe-sis process, a bimetallic molecular compound with chemical formula [Cl2TiZn（dmae）4] （dmae=dimethylaminoethanol） was synthesized and its chemical composition was deter-mined by elemental analysis. The obtained compound has shown excellent solubility in common organic solvents, a prerequisite for its use in sol gel method as SSP. The SSP ob-tained was controllably hydrolyzed by adding equimolar amount of water using ethanol as solvent to get ZnO/TiO2 nanocomposite gel. The resulting gel was precipitated at pH=9 and sintered at 200 ℃ （T200）, 400℃ （T400）, and 600℃ （T600）. The XRD analyses have shown that the as synthesized （non-sintered, T00） powder was amorphous. However, the crystallinity improved upon sintering, and the XRD analyses revealed that the resulting nanomaterials were composed of mixed oxides i.e., ZnO and TiO2. The ZnO was in wurtzite （hexagonal） while the TiO2 was in brookite （orthorhombic） phase. The increase in particlesize was further confirmed from BET analysis and SEM micrographs. The IR spectra ob-tained for the resulting powder have shown the peculiar vibrational bands for Zn-O and Ti-O. Furthermore, the IR spectra revealed that the non-sintered ZnO/TiO2 nanocomposite had significant number of OH group which was removed upon sintering. The photocatalytic activities of the ZnO/TiO2 nanocomposites were tested. All the samples have shown good photocatalytic activities. However, the T400 has shown higher activity than the T00, T200, and T600. The higher photocatalytic activity of T400 than T00, T200, and T600 may be due to improved crystallinity which ensures efficient grain boundary interfaces.展开更多
Pure γ-Gd2S3 was synthesized by the thermolysis of a single Gd[S2CN（C4H8）]3 phen complex precursor in a flow of argon carrier gas containing sulfur vapor. The complex precursor was decomposed into amorphous Gd2S3 a...Pure γ-Gd2S3 was synthesized by the thermolysis of a single Gd[S2CN（C4H8）]3 phen complex precursor in a flow of argon carrier gas containing sulfur vapor. The complex precursor was decomposed into amorphous Gd2S3 and carbon at about 350 ℃. Crystalline y-Gd2S3 could be achieved at temperature exceeding 600 ℃, and the obtained γ-Gd2S3 presented a very high degree of crystallinity at 800 ℃. Carbon prevented the formation of Gd2O2S impurity in the preparation of y-Gd2S3. However, the carbon blackened the product. At temperature ≥ 1000 ℃, the residual carbon impurity could be efficiently removed by introducing sulfur into the system for the volatile CS2 could be formed in situ via the reaction of sulfur with the deposited carbon. In the meantime, S also promoted the crystallization of γ-Gd2S3 remarkablely.展开更多
A new heterobimetallic nitrilotriacetatoperoxotitanate complex with the formula of [Mn（H2O）5]2[Ti（O2）2O（nta）2]·7H2O （1, C6H6O6N = H3nta） has been isolated in pure crystals. It was characterized by element...A new heterobimetallic nitrilotriacetatoperoxotitanate complex with the formula of [Mn（H2O）5]2[Ti（O2）2O（nta）2]·7H2O （1, C6H6O6N = H3nta） has been isolated in pure crystals. It was characterized by elemental analyses, IR, thermal analysis （TGA） and single-crystal X-ray diffraction. Complex 1 crystallizes in monoclinic, space group C2/c with a = 15.088（3）, b = 13.311（3）, c = 17.741（4） , β = 100.92（3）°, Z = 4, V = 3498.6（12） 3, Mr = 968.19, Dc = 1.838 g/cm3, μ = 1.266 mm-1, F（000） = 1992, R = 0.0337 and wR = 0.0819. Single-crystal X-ray analysis reveals that the titanium atom is N,O,O＇,O＇＇-chelated by the nitrilotriacetate and O,O＇-chelated by the peroxo group, and is coordinated to the bridging O atom in an overall pentagonal-bipyramidal geometry. The manganese ions in the compound are both 6-coordinated by five water molecules and one bridged carboxylato oxygen atom. A decameric water cluster consisting of a cyclic water hexamer in a boat fashion is also found in complex 1. The TGA and XRD results prove that 1 undergoes facile thermal decomposition to form the mixture of Mn2O3 and TiO2 at 600～800 ℃, and pure MnTiO3 at 900 ℃.展开更多
文摘Stable binary single source precursors （SSP） for the deposition of thin films of ceramic semiconductors of composition SnO·GeO were synthesized by close circuit chemical vapour deposition （CCCVD） method. Elemental analysis and spectroscopic techniques were used to characterize the precursors. Scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS） were employed to characterize the thin films. Resistivity measurements were conducted to show that the films are of semiconducting nature.
文摘Single source molecular precursors （SSPs） provide an opportunity to get control over the microstructure of nanomaterials at atomic level. A SSP was designed and developed for the synthesis of ZnO/TiO2 nanocomposite by sol gel method. In a typical synthe-sis process, a bimetallic molecular compound with chemical formula [Cl2TiZn（dmae）4] （dmae=dimethylaminoethanol） was synthesized and its chemical composition was deter-mined by elemental analysis. The obtained compound has shown excellent solubility in common organic solvents, a prerequisite for its use in sol gel method as SSP. The SSP ob-tained was controllably hydrolyzed by adding equimolar amount of water using ethanol as solvent to get ZnO/TiO2 nanocomposite gel. The resulting gel was precipitated at pH=9 and sintered at 200 ℃ （T200）, 400℃ （T400）, and 600℃ （T600）. The XRD analyses have shown that the as synthesized （non-sintered, T00） powder was amorphous. However, the crystallinity improved upon sintering, and the XRD analyses revealed that the resulting nanomaterials were composed of mixed oxides i.e., ZnO and TiO2. The ZnO was in wurtzite （hexagonal） while the TiO2 was in brookite （orthorhombic） phase. The increase in particlesize was further confirmed from BET analysis and SEM micrographs. The IR spectra ob-tained for the resulting powder have shown the peculiar vibrational bands for Zn-O and Ti-O. Furthermore, the IR spectra revealed that the non-sintered ZnO/TiO2 nanocomposite had significant number of OH group which was removed upon sintering. The photocatalytic activities of the ZnO/TiO2 nanocomposites were tested. All the samples have shown good photocatalytic activities. However, the T400 has shown higher activity than the T00, T200, and T600. The higher photocatalytic activity of T400 than T00, T200, and T600 may be due to improved crystallinity which ensures efficient grain boundary interfaces.
基金Project supported by National Natural Science Foundation of China(60979003)New Century Educational Talents Plan of Chinese EducationMinistry,China(NCET-10-0171)+1 种基金Fundamental Research Funds for the Central Universities(2011QN153,2012QN065,2012QN068,2012TD018)Scientific Research Fund of Zhejiang Provincial Education Department(Y201121038)
文摘Pure γ-Gd2S3 was synthesized by the thermolysis of a single Gd[S2CN（C4H8）]3 phen complex precursor in a flow of argon carrier gas containing sulfur vapor. The complex precursor was decomposed into amorphous Gd2S3 and carbon at about 350 ℃. Crystalline y-Gd2S3 could be achieved at temperature exceeding 600 ℃, and the obtained γ-Gd2S3 presented a very high degree of crystallinity at 800 ℃. Carbon prevented the formation of Gd2O2S impurity in the preparation of y-Gd2S3. However, the carbon blackened the product. At temperature ≥ 1000 ℃, the residual carbon impurity could be efficiently removed by introducing sulfur into the system for the volatile CS2 could be formed in situ via the reaction of sulfur with the deposited carbon. In the meantime, S also promoted the crystallization of γ-Gd2S3 remarkablely.
基金supported by the Fundamental Research Funds for the Central Universities, SCUT (No. 2009ZM0313) the National Natural Science Foundation of China (B5080320)
文摘A new heterobimetallic nitrilotriacetatoperoxotitanate complex with the formula of [Mn（H2O）5]2[Ti（O2）2O（nta）2]·7H2O （1, C6H6O6N = H3nta） has been isolated in pure crystals. It was characterized by elemental analyses, IR, thermal analysis （TGA） and single-crystal X-ray diffraction. Complex 1 crystallizes in monoclinic, space group C2/c with a = 15.088（3）, b = 13.311（3）, c = 17.741（4） , β = 100.92（3）°, Z = 4, V = 3498.6（12） 3, Mr = 968.19, Dc = 1.838 g/cm3, μ = 1.266 mm-1, F（000） = 1992, R = 0.0337 and wR = 0.0819. Single-crystal X-ray analysis reveals that the titanium atom is N,O,O＇,O＇＇-chelated by the nitrilotriacetate and O,O＇-chelated by the peroxo group, and is coordinated to the bridging O atom in an overall pentagonal-bipyramidal geometry. The manganese ions in the compound are both 6-coordinated by five water molecules and one bridged carboxylato oxygen atom. A decameric water cluster consisting of a cyclic water hexamer in a boat fashion is also found in complex 1. The TGA and XRD results prove that 1 undergoes facile thermal decomposition to form the mixture of Mn2O3 and TiO2 at 600～800 ℃, and pure MnTiO3 at 900 ℃.
