Fabrication and characterization of Ag-TiO2 multiphase nanocomposite thin films with enhanced photocatalytic activity
Fabrication and characterization of Ag-TiO2 multiphase nanocomposite thin films with enhanced photocatalytic activity
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DOI：
10.1016/j.apcatb.2005.03.009
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发表时间：
2005-10
影响因子：
22.1
通讯作者：
Jiaguo Yu;J. Xiong;B. Cheng;Shengwei Liu
中科院分区：
文献类型：
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作者：
Jiaguo Yu;J. Xiong;B. Cheng;Shengwei Liu
以六氟钛酸铵、银银和硼酸的混合水溶液为原料，采用液相沉积法（LPD）在石英衬底上制备了Ag-TiO 2复相纳米复合薄膜。Ag+掺杂抑制了TiO 2的晶粒生长。然而，银离子不仅促进（或催化）板钛矿相的形成，而且降低了金红石向金红石的相变温度。随着AgNO 3浓度的增加，复合薄膜的透过率和带隙减小，但表面等离子体吸收峰强度增加，峰位向长波方向移动。当AgNO 3浓度大于0.03M时，所制备的样品由金红石、板钛矿、金红石和金属银相组成，其粒径范围为5- 30 nm。当AgNO 3浓度在0.03 ~ 0.05范围内时，该方法制备的Ag-TiO 2复相复合薄膜的光催化活性是纯TiO 2薄膜的6.3倍以上。这是由于Ag-TiO 2复相纳米复合薄膜中存在着Ag/金红石、Ag/板钛矿、Ag/Al 2 O3、Ag/金红石等异质结。
Ag–TiO2multiphase nanocomposite thin films were prepared on quartz substrates by the liquid phase deposition (LPD) method from a mixed aqueous solution of ammonium hexafluouotitanate, silver nitrate and boric acid under ambient temperature and atmosphere followed by calcination at 500°C for 1h. The grain growth of anatase was depressed upon Ag+doping. However, silver ions not only promoted (or catalyzed) the formation of brookite phase but also reduced the phase transformation temperature of anatase to rutile. With increasing AgNO3concentration, the transmittance and band gap of the composite thin films decreased; however, the intensity of surface plasmon absorption (SPA) peaks increased and their peak position shifted to a longer wavelength range. When AgNO3concentration was higher than 0.03M, the prepared samples consisted of anatase, brookite, rutile and metal silver nanocrystal particles, and their grain size ranges were 5–30nm. The photocatalytic activity of the Ag–TiO2multiphase nanocrystal composite thin films prepared by this method exceeded that of pure TiO2thin films by a factor of more than 6.3 when AgNO3concentration was kept in the range of 0.03–0.05. This was attributed to the fact that there were many hetero-junctions, such as anatase/rutile, anatase/brookite, Ag/anatase, Ag/rutile and so on, existed in the Ag–TiO2multiphase nanocomposite films.