排序方式: 共有49条查询结果,搜索用时 187 毫秒
41.
42.
Composition and morphology of complicated copper oxalate powder 总被引:2,自引:1,他引:1
In Cu(Ⅱ)-C2O42--NH3-NH4+-H2O system, complicated copper oxalate powders were synthesized by coordination-precipitation process with ammonium oxalate as precipitating agent. The composition and morphology of the powders were characterized by chemical analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR), and thermogravimetric and differential thermal analysis (TGA-DTA). The effects of temperature, copper ion concentration and pH value were investigated. The experimental results show that pure copper oxalate hydrate is prepared below a critical pH value of 6.0, whereas the powder turns to be a complicated copper salt combined with NH3 over the pH value. Probable chemical formula, CuC2O4·x(NH3) ·yH2O can be assumed, where x and y relate to experimental conditions. Technological parameters, such as temperature, initial copper concentration and solution pH value, have significant effects on particle size, morphology and dispersion of the powders. Powders with various morphologies, pie shape, spindle shape and rod shape, can be synthesized under certain technological conditions. 相似文献
43.
通过选择性控制合成条件,制备一种新型的纤维状镍钴合金粉末前驱体。该前驱体中镍、钴摩尔配比精确。采用X-射线衍射仪(XRD)、扫描电镜(SEM)、红外光谱(FT-IR)和能谱(EDS)研究前驱体粉末的成分与形貌;考察溶液pH值、反应温度、金属离子浓度和表面活性剂对前驱体粉末的形貌和分散性的影响。结果表明:前驱体的形貌取决于前驱体中氨的含量,这种纤维状前驱体为一种复杂的含氨草酸镍钴复盐。形貌控制合成纤维状镍钴合金粉末前驱体的最佳条件为:氨作为配位剂和pH值调节剂,草酸为沉淀剂,反应温度为50~65°C,镍、钴离子总浓度为0.5~0.8mol/L,PVP为分散剂,溶液pH值控制在8.0~8.4. 相似文献
44.
45.
46.
采用草酸盐前驱体合成Ti4+、Mg2+掺杂正极材料Li(Ni1/3Co1/3-xMn1/3)MxO2(M=Ti, Mg).利用XRD和SEM对其结构和形貌进行表征,并采用循环伏安、交流阻抗、恒流/恒压充放电测试其电化学性能.结果表明:Ti4+、Mg2+掺杂后晶胞体积增大,大倍率充放电时LiNi1/3Co1/3Mn1/3O2的电化学反应阻抗Rct降低,其大倍率充放电性能得到改善,Ti4+掺杂效果更好;当掺杂量x=0.025时,材料晶型完整,具有单一的a-NaFeO2层状结构;1C倍率时Li(Ni1/3Co1/3-0.025Mn1/3)Ti0.025O2的第二循环放电容量为143.2 mA-h/g,2C时为128.0 mA-h/g,经100次循环后容量分别为132.5和115.8 mA-h/g,容量保持率为92.53%和90.47%. 相似文献
47.
48.
49.
通过湿法球磨联合煅烧方法制备软铋矿型光催化材料Bi12MnO20,其光吸收能力覆盖200~2200 nm光谱范围。Bi12MnO20的晶体结构可以视为Mn4+掺入到亚稳立方γ-Bi2O3的四面体中所得,并且Bi12MnO20的能带结构中出现禁带宽度为1.25 e V的子带隙。这种能带结构的优化有利于Bi12MnO20光催化剂加速转化溶液中O2为超氧自由基(·O2-),以改善光催化降解过程中的电荷分离和转移。结果表明,在模拟阳光照射下,Bi12MnO20对pH 8溶液中浓度为10 mg/L的孔雀石绿降解率达到95%以上。经过4次光降解实验后,Bi12MnO20对孔雀石绿的降解率保持在74.9%。 相似文献