掺Ag量对绢云母负载纳米二氧化钛性能的影响

以绢云母为载体,采用水解-沉淀法制备出了绢云母负载纳米TiO2粉体（TiO2/M）,在粉体表面沉积不同量的Ag2CO3,经400℃焙烧,制得不同掺Ag量的绢云母负载TiO2光催化剂,采用TG、XRD、SEM、EDS、UV等手段对样品进行了性能表征;并以日光色镝灯为光源,甲基橙为模拟污染物检测其光催化活性,研究了Ag的掺杂量对粉体中TiO2晶相结构、粒度和光催化性能的影响。结果表明：纳米TiO2均匀负载在绢云母上形成包覆层,Ag的掺杂抑制了TiO2晶粒的长大,减缓锐钛矿向金红石相的转变,同时Ag的掺杂形成新的能级结构,随Ag＋/Ti4＋摩尔比的增加,样品对光的吸收边逐渐红移至440～520 nm,具有明显的可见光响应,当Ag＋/Ti4＋=0.05时,制得样品对甲基橙的光催化降解率是没有掺Ag的样品的1.5倍,相同条件下重复利用4次,该样品60 min对甲基橙的降解率仍然可达34%。

Effects of Ag-concentration on Photocatalytic Activities of Ag-doped TiO2 Film on Mica

Ag-doped TiO2/M samples with photocatalytic activity under visible light were directly prepared by hydrolysis-precipitation,where Ag2CO3 was the resource of Ag.The as-prepared samples were characterized by TG,XRD,SEM,EDS and UV methods.The photocatalytic activity of the samples were tested by taking methyl orange as pollution models and using the solar dysprosium-color as light source.The results show that： TiO2 nanoparticles formed a homogeneous fixed coating on the surface of mica.Ag-doping could be benefical for TiO2 dispersion and slow anatase to rutile phase transformation.Ag-doped could form a new energy level above the valence band of TiO2 which can extend the adsorption edge to 440～520 nm,and with the compositions（Ag＋/Ti4＋=0.05）,the photocatalytic degradation rate of methyl orange can reach 1.5 times higher than those samples without Ag-doping.the degradation rate of methyl orange is still up to 34% when repeated this process four times under the same conditions.