F离子掺杂TiO2的性能研究

以NH4F为掺杂剂，采用溶胶-凝胶法制备F离子掺杂型TiO2光催化剂，对其进行XRD、XPS和PL表征，结果表明，F离子掺杂ToO2由于Ti—F配位体的形成而能抑制金红石相的生成，同时F离子掺杂能增加TiO2表面缺陷浓度并降低Ti2P键的结合能，另外，由于F离子能取代Ti—OH配位体而降低了表面羟基氧浓度．光催化研究结果表明，F离子掺杂提高了TiO2光催化活性近1．5倍．     

F-掺杂改性锂锰一次电池的性能研究

将(NH4)HF2与MnO2混合均匀后经热处理制备了掺F-的MnO2正极材料MnO1.99F0.01,并制备成锂锰一次电池。XRD测试表明F-掺杂改变了MnO2正极材料的结构;电化学性能测试表明F-掺杂提高了锂锰一次电池的放电比容量,放电比容量从200m Ah/g提高到225m Ah/g;此外,F-掺杂改善了Li/MnO2电池的储存寿命,储存寿命增加到16a。     

Study of the properties of undoped and fluorine doped zinc oxide nanoparticles

ZnO and ZnO:F nanoparticles were successfully prepared by precipitation in the presence of oxalic acid. This procedure yields ZnO and ZnO:F nano-arrangements of different lengths consisting of chains of quasi-spherical nanoparticles of ∼ 30 nm in size. Only the wurtzite ZnO structure was detected for both undoped and fluorine doped ZnO nanoparticles. By absorption and photoluminescence measurements, a diminishing of singly ionized oxygen vacancies was detected when fluorine is present in the nanoparticles; while a blue shift of the exciton absorption was observed. Additionally, by NIR reflectance measurements, the creation of free carriers by the fluorine doping of ZnO nanoparticles was observed.     

Hydrogenated F-doped TiO2 for photocatalytic hydrogen evolution and pollutant degradation

In this work, both hydrogenated and F-doping strategies are adopted to synergistically enhance the photocatalytic properties of TiO₂ under solar light irradiations. The hydrogenated F-doping TiO₂ is successfully synthesized by a facial two-step method and characterized with physicochemical and spectroscopy methods. It is found that the F-doping strategy can effectively enhance the UV-light absorption property of TiO₂, and the hydrogen treatments can further increase the light absorption performance of TiO₂ in the visible light region. As a result, the hydrogenated F-doping TiO₂ exhibits better photocatalytic properties than pure, hydrogenated or F-doped TiO₂, in either hydrogen production or organic pollutant degradation. The present work provides a suitable and synergistic strategy to enhance the photocatalytic activity of TiO₂.     

无钴镍基正极材料LiNi0.7Mn0.3O2 氟掺杂改性研究

以硫酸盐为原料,采用共沉淀-固相反应法成功制备了LiNi_(0.7)Mn_(0.3)O_(2-x)F_x(x=0,0.01,0.02,0.03)正极材料。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、电化学阻抗谱(EIS)、循环伏安法(CV)、充放电测试等系统地研究了F掺杂对无钴镍基正极材料LiNi_(0.7)Mn_(0.3)O_(2-x)F_x(x=0,0.01,0.02,0.03)结构和电化学性能的影响。X射线衍射结果表明,所有样品均具有典型的α-NaFeO_2层状结构,随着F掺杂量的增加,材料晶胞体积逐渐增大;扫描电镜结果显示,F掺入使材料的一次颗粒形状更加规则、均匀、致密,且尺寸更大、结晶度更高。X射线光电子能谱(XPS)测试结果表明,F掺入之后,材料中二价镍的含量增加,其他元素的化合价保持不变。电化学阻抗谱(EIS)和循环伏安(CV)曲线数据证实掺适量F可以减小电池的电化学转移内阻(Rct)和电极的极化作用。F掺杂虽然减小了材料的首次放电容量,但提高了材料的首次库伦效率和循环稳定性。