过渡金属离子掺杂对TiO2纳米尺寸及其相结构的影响

利用酸催化的溶胶-凝胶法合成了一系列不同掺杂量的Fe3 /TiO2、Cr3 /TiO2纳米复合微粒.用XRD和TEM研究了Fe3 、Cr3 的掺杂对TiO2纳米粒子尺寸和相结构的影响.结果表明:掺杂离子不同,对TiO2纳米粒子尺寸和相结构的影响不同.在所研究的掺杂量范围内(x:0.0000～0.1000),TiO2纳米粒子的粒径随Cr3 掺杂量的增加呈减小的趋势,但幅度不大;而Fe3 的掺杂则会引起TiO2粒子的团聚和晶粒的长大;由XRD分析可知:在掺杂量范围内,不会发生Fe2O3、Cr2O3等相的偏析,但Fe3 的掺杂引起了TiO2在低温条件下由锐钛矿向金红石的相转变.通过UV-Vis光谱的研究发现:Fe3 、Cr3 的加入,可以使TiO2对光的吸收拓展到可见区,同时随着掺杂量的增加,对可见光的吸收强度显著增强.

Effect of doped Fe3+ and Cr3+ on phase and size of TiO2 nanoparticles

Fe~(3 )and Cr~(3 )-doped TiO_2 nanoparticles with different doping amount were successfully synthesized using an acid-catalyzed sol-gel procedure.XRD,TEM,and UV-Vis techniques were used to characterizing the nanocomposites with regard to their phase,size and absorption properties.TEM showed that the average size of the particles was about 10nm.The size of Cr~(3 )/TiO_2 particles slightly decreased with increasing the amount of Cr~(3 ) while the Fe~(3 )/TiO_2 particles had developed an aggregation.XRD results indicated that in the range of 0.0000~0.1000,Fe_2O_3 and Cr_2O_3 phases did not appear while doped Fe~(3 ) lead to conversion of TiO_2 from anatase to rutile.UV-Vis spectra showed a red shift and a significant increase of absorption intensity in the visible region with increasing amount of doping Fe~(3 ) and Cr~(3 ).