(廊坊師范學(xué)院 化學(xué)與材料科學(xué)學(xué)院，廊坊 065000)
摘 要: 以光還原沉積法對TiO2/SnO2薄膜進(jìn)行Ag改性，制備Ag-TiO2/SnO2納米薄膜，討論紫外光照時間、光照強(qiáng)度、AgNO3濃度等工藝條件對光催化活性的影響。用XRD和SEM對薄膜的結(jié)構(gòu)、表面形貌和化學(xué)組成進(jìn)行表征，以甲基橙為模擬污染物對光催化性能進(jìn)行測定。結(jié)果表明：在最佳條件下制備的Ag-TiO2/SnO2薄膜，Ag擔(dān)載量為0.51%(摩爾分?jǐn)?shù))，Ag簇直徑在30~90 nm之間；薄膜具有較高的光催化活性，對甲基橙的降解率是修飾前TiO2/SnO2薄膜的2.02倍，是相同質(zhì)量TiO2/ITO薄膜的3.30倍；催化活性的提高，源于反應(yīng)機(jī)理的改變；薄膜中Ag-TiO2異質(zhì)結(jié)的引入，一方面進(jìn)一步促使光生電荷的分離，另一方面加速了氧氣與激發(fā)電子的還原反應(yīng)。
關(guān)鍵詞：TiO2/SnO2薄膜；銀；光沉積；光催化；降解；甲基橙
關(guān)鍵字: TiO2/SnO2薄膜；銀；光沉積；光催化；降解；甲基橙
their photocatalytic activity for methyl orange
（Faculty of Chemistry and Material Science, Langfang Teachers College, Langfang 065000, China）
Abstract: Silver-modified TiO2/SnO2 thin films (Ag-TiO2/SnO2 thin films) were prepared by photodeposition method. The effects of preparation conditions on the photocatalytic activity of Ag-TiO2/SnO2 thin films were discussed. The surface morphology, chemical composition and structure of the film were characterized by SEM and XRD, and its photocatalytic property were evaluated with methyl orange as model compound. The results show that the optimum content of Ag on the film surface is 0.51% (mole fraction), and the diameters of Ag particles are about 30−90 nm. The Ag-TiO2/SnO2 film is photocatalytically more active than TiO2/SnO2 and TiO2/ITO. The photocatalytic degradation rate of Ag-TiO2/SnO2 film is 2.02 times as that of the TiO2/SnO2 film, and 3.30 times as that of the TiO2/ITO film. The increasing photocatalytic activity is mainly duo to the change of reaction mechanism. The heterojunction of Ag-TiO2 in Ag-TiO2/SnO2 film efficiently promotes the separation of charges, and accelerates the reaction of excited electrons with oxygen in photocatalytic degradation for methyl orange.
Key words: TiO2/SnO2 nanofilm; silver; photodeposition; photocatalysis; degradation; methyl orange
