Structural Analysis and Magnetic Properties of Gd-Doped Li-Ni Ferrites Prepared Using Rheological Phase Reaction Method

A series of Gd-doped Li-Ni ferrites with the formula of LiNi0.5GdxFe2-xO4 where x = 0.00 - 0.08 in steps of 0.02, were prepared by thermolysis of oxalate precursors obtained by rheological phase reaction. The structure, morphology, and the magnetic properties of the samples were characterized by powder X-ray diffraction （XRD）, atomic force microscopy （AFM） and a vibrating sample magnetometer （VSM）. A single spinel phase was obtained in the range of x = 0.00 - 0.04. The lattice parameters of the Gd-doped samples were larger than that of pure Li-Ni ferrite, and increased in the range of 0.00 ≤ x ≤ 0.04, then decreased up to x = 0.08, because of the formation of the secondary phase （Gd- FeO3）. All samples were spheric particles with an average size of about 100 nm, but agglomerated to some extent. The hysteresis loops indicated that the saturation magnetization decreased gradually with increasing Gd content, while the variation of coercivity was related to the microstructure of the Gd-doped samples.

Rheological Phase Synthesis and Characterization of Copper Monosalicylate

A new structural copper (II) monosalicylate, Cu(OC6H4C02)·H20, was synthesized by the rheological phase reaction method from salicylic acid and copper oxide in 1∶1 mole ratio. The structure was characterized by powder X-ray diffraction, IR and thermogravimetry. The Cu(OC6 H4 CC2)·H20 belongs to monoclinic system, with cell dimension:a=2.136 28(67),b=0. 657 84(22),c=l. 594 09(50) nm, β=108.434(25) ,V=2.125 28(83) nm3,Z=12, Dcalc=2.041 kg·L?1,D obs=2.003 kg·L?1. The crystal water was lost at 96–250°C. The determined magnetic moment and magnetic susceptibility were 1. 947 B. M. and 6. 546×10?6 (287. 20 K), respectively.

Preparation by a Rheological Phase Reaction Method and Thermal Decomposition Reaction Mechanism of Nickelous Salicylate Tetrahydrate

The single crystal nickel salicylate tetrahydrate was prepared with the rheological phase reaction method from nickelous hydroxide and salicylic acid. The crystal structure was determined. It is monoclinic, space group P2 1/n, a= 0.678 74 (3), b=0.515 91(2), c =2.313 30(9) nm, β= 90.928 6(17)° , V =0.809 94(6) nm 3, Z=2, ρ calcd = 1.661 g\5cm -3 . Final R indices: R =0.027 9 and wR= 0.065 0 \[I >2σ(I)\]. The thermal decomposition mechanism in an inert atmosphere was investigated via TG, DTG and DTA. The thermal decomposition products were characterized with IR and micro\|powder X\|ray diffraction method. A new coordination polymer (NiC 6 H 4 O) n as an intermediate product and nanoscale metal nickel were obtained in the ranges of 364\|429 ℃ and 429\|680 ℃, respectively.

Synthesis and Characterization of a Novel Compound SnDy2O4

A new phase, the rare earth complex oxide SnDy2O4 was synthesized by the thermal decomposition of its oxalate precursor that was prepared by rheological phase reaction method. TG, IR, XRD and EPS were used to prove the formation of the compound SnDy2O4. The structure of SnDy2O4 was refined by Rietveld analysis. SnDy2O4 is cubic, a = 7.40366 ? V = 405.82 ?, Z = 4.

Structural and Magnetic Properties of La-Doped Li-Ni Ferrite

A series of polycrystalline La-doped Li-Ni ferrites LiNi_ 0.5La_xFe_ 2-xO_4 (where x=0.0～0.08 in steps of 0.02) were prepared by thermolysising of oxalate precursors which were obtained by rheological phase reaction. Results were observed by powder X-ray diffractometer (XRD) on samples indicate that all doped ferrites have the major spinel phase, and the single spinel phase is obtained in La content x≤0.04. The lattice parameter increases in the range of x=0～0.04, then decreases up to x=0.08. The hysteresis loops show that the value of saturation magnetization is less than that of the pure Li-Ni ferrite except for x=0.04, while the coercivity increases with the La content.

The Application of Lights-Conversed Polyethylene Film for Agriculture

Lanthanum-rhodamine (6G and B) complexes were synthesized by Rheological Phase Reaction Method. Lanthanum-rhodamine (6G and B) complexes doped polyethylene films which have a function of lights-conversion were prepared. The emission and excitation spectra were measured. The experiments of growing seedling and culture were carried out in the shed built with doped and undoped polyethylene films. Lanthanum-rhodamine doped polyethylene films which have a function of lights-conversion can efficiently convert the green light in the sunlight to the red light for photosynthesis of crops, to promote the maturing of crops and raise the yield of crops.

Synthesis,Characterization and Properties of LiFePO_4/C Cathode Material

Lithium iron phosphate coated with carbon （LiFePO4/C） was synthesized by improved solid-state reaction using comparatively lower temperature and fewer sintering time. The carbon came from citric acid, which acted as a new carbon source. It was characterized by thermogravimetry and differential thermal analysis （TG/DTA）, X ray diffractometer （XRD）, Element Analysis （EA） and Scanning electron microscope （SEM）. We also studied the electrochemical properties of the material. The first discharge capacity of the LiFePO4/C is 121 mAh·g^-1 at 10 mA·g^-1 at room temperature. When the current density increased to 100 mA·g^-1, the first discharge capacity decreased to 110 mAh·g^-1 and retained 95% of the initial capacity after 100 cycles. The LiFePO4/C obtained shows a good electrochemical capacity and cycle ability at a large current density.

Studies of Nano-sized Co_3O_4 as Anode Materials for Lithium-ion Batteries

The structural evolution of the Co 3O 4 fine powders prepared by rheological phase reaction and pyrolysis method upon different temperature has been investigated using X ray diffraction (XRD) topography. The electrochemical performance of Co 3O 4 electrode materials for Li ion batteries is studied in the form of Li/Co 3O 4 cells. The reversible capacity as high as 930 mAh/g for the Co 3O 4 sample heat treated at 600 ℃ is achieved and sustained over 30 times charge discharge cycles at room temperature. The detailed information concerning the reaction mechanism of Co 3O 4 active material together with lithium ion is obtained through ex situ XRD topography, X ray photoelectron spectroscopy (XPS) analysis and cyclic voltammetry (CV) technique. And it is revealed that a “two step” reaction is involved in the charge and discharge of the Li/Co 3O 4 cells, in which Co 3O 4 active material is reversibly reduced into x Co· (3- x )CoO and then into metallic Co.

Synthesis and Thermal Decomposition Mechanism of Rare Earth (RE=La, Y, Gd) Salicylates

The rare earth (RE=La, Y, Gd) salicylates were synthesized by the rheological phase reaction method. The complexes were characterized by elemental analysis, infrared spectra (IR), X-ray powder diffraction (XRD) and thermal gravity analysis (TG). They can be represented by general formula RE(HSal)3 (RE=La, Y, Gd; HSal= C6H4(OH)COO). The crystals of them are monoclinic and have layered structure. The mechanism of thermal decomposition of rare earth salicylates was studied by using TG, DTA, IR and gas chromatography-mass spectrometry (GC-MS). The thermal decomposition of the rare earth salicylates in nitrogen gas proceeded in three stages: firstly, they were decomposed to form RE2(Sal)3(Sal=C6H4OCOO) and salicylic acid; then, RE2(Sal)3 were decomposed further to form RE2O(CO3)2 and some organic compounds; finally, RE2O(CO3)2 were decomposed to form rare earth metal oxides (RE2O3) and carbon dioxide. The organic compounds obtained from the second step of the reaction are mainly dibenzofuran, xanthenone, 6H-benzo[c]chromen-6-one, 6-phenyl-6H-benzo[c]chromene, and 1,3-diphenyl-1, 3-dihydro-2-benzofuran.