Al6(OH)18(H2O)6的结构及成键方位的从头算及密度泛函分析Ⅱ

用RHF法6-31G、6-31G*、6-31G**水平的量子化学从头算及RB3LYP/6-31G、B3LYP/6-31G*,B3LYP/6-31G**水平的密度泛函方法,采用SCRF=Dipole溶剂模型,计算了三水铝石有利生长基元最优结构Al6(OH)18(H2O)6的总能量、布居数、原子静电荷等.计算结果表明,桥联OH基团更易成键,Al6(OH)18(H2O)6较为有利的成键方位是桥联OH基团方位.     

Li2CO3、NiO和电解MnO2合成高容量LiNi0.5Mn1.5O4及其表征

Well-developed crystalline LiNi_0.5Mn_1.5O₄ was prepared by solid-state reaction using Li₂CO₃, NiO and electrolytic MnO₂ at high heating and cooling rate. X-ray diffraction (XRD) patterns and scanning electron microscopic (SEM) images showed that LiNi_0.5Mn_1.5O₄ synthesized at 900 ℃ and 950 ℃ had cubic spinel structure with clearly defined shape. LiNi_0.5Mn_1.5O₄ spinel phase decomposed at 1 000 ℃ accompanying with structural and morphological degradation. TG measurement revealed that the weight loss during heating process could be mostly gained in cooling process, and the upward tendency of weight loss during heating process decreased, while that of irreversible weight loss rapidly increased with the increase of temperature. LiNi_0.5Mn_1.5O₄ powders prepared at 900 ℃ for 12 h delivered the maximum discharge capacity of 134 mAh·g^-1 with good cyclic performance at 2/7 C. In addition, by adjusting the calcination time at 900 ℃, the capacity and cycling performance of LiNi_0.5Mn_1.5O₄ were further enhanced.     

不同晶型WO3的光催化析氧活性研究

以仲钨酸铵为原料,分别采用高温煅烧、低温淬火与高温煅烧、自然冷却方法制备了正交晶型和单斜晶型的WO3,研究了两种不同晶型WO3的光催化析氧活性,结果表明,正交晶型WO3的活性高于单斜晶型WO3.同时对光催化剂WO3的用量以及电子受体Fe3 的浓度等因素对光催化析氧活性的影响进行了研究.     

铝酸钠溶液晶种分解附聚过程研究

苛性钠浓度Na2Ok=140g·L-1,苛性比αk=1.37的铝酸钠溶液中,在种子比Ks=0.25,温度T=76℃的条件下对附聚过程进行了研究.通过粒度分布对时间变化的分析,探讨了晶种附聚过程的规律.实验发现细粒子在短时间内就可以附聚完全.两相邻时间段粒度分布曲线的交点rp在30u m左右,在一定时间内rp值基本保持不变,但在整个分解时间内略有右移.rp以下的粒子附聚可能性大,rp以上的粒子附聚可能性小.     

簇合物[Et4N]2[Mo2S4(SCH2CH2S)2]的合成及晶体结构

以(NH4)2MoS4,Et4NBr,HSCH2CH2SH为原料合成了新的簇合物——[Et4N]2[Mo2S4(SCH2CH2S)2],其结构经X射线四圆衍射仪,IR。UV及元素分析确证。其晶体属单斜晶系。晶胞参数为：a=1．0304(8)nm,b=1．4158(8)sin。c=1．1417(1)nm,V=1．63801nm^3,z=4。晶体结构经块状矩阵最小二乘法修正后,最终偏离因子R=0．084。