Photocatalytically deposited silver nanoparticles on mesoporous TiO2 films
Photocatalytically deposited silver nanoparticles on mesoporous TiO2 films
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DOI：
10.1021/la981783t
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发表时间：
2000-03-07
期刊：
影响因子：
3.9
通讯作者：
Siokou, A
中科院分区：
文献类型：
--
作者：
Stathatos, E;Lianos, P;Siokou, A
利用二氧化钛在非均相光催化下进行有机和无机水污染物的全氧化是近年来广泛研究的对象。许多研究都致力于通过沉积贵金属来改善二氧化钛的光活性。1-4特别是，银在TiO2胶体颗粒上的沉积已经得到了广泛的关注，超越了光催化降解。因此，金属银可以光催化沉积在TiO2上，该工艺可用于回收银，例如从废弃的摄影废水中回收银。如果在TiO2电极中加入金属颗粒，则电子的光激发增强。因此，在可见区域的阳极光电流的增加被观察到对于Au和Ag粒子分散电极，这被认为是由金属粒子的表面等离子体共振的结果。热催化或光催化制备的纳米银与二氧化钛和二氧化硅相结合的金属陶瓷材料具有有趣的电学和光学特性。金属岛之间的电子隧穿可以实现导电性，同时提供光学透明度，这要归功于金属颗粒的小尺寸。在玻璃表面涂上一层银盐，然后再进行热处理，这种技术已经有几个世纪的经验了。我们现在知道，颜色是由与银纳米粒子相关的表面等离子体频率获得的。考虑到银金属氧化物组合的所有这些有趣的应用，我们在目前的工作中光催化沉积了纳米银在二氧化钛纳米颗粒薄膜上，并通过原子力显微镜（AFM）、紫外可见光谱和x射线光电子能谱（XPS）对它们进行了研究。本研究的新颖之处在于，介孔TiO2薄膜和纳米银颗粒层的制备条件简单直接，提供了一种光学上有趣的材料。
Use of titania in heterogeneous photocatalysis for the total oxidation of organic and inorganic water pollutants is an object of extensive research in the recent years. Many studies have been devoted to the improvement of titania photoactivity by depositing noble metals. 1-4 In particular, deposition of silver on TiO2 colloidal particles has received an extended interest that goes beyond photocatalytic degradation. Thus metallic silver can be photocatalytically deposited on TiO2, and this process can be used in silver recovery, eg, from waste photographic effluents. 5 The photoexcitation of electrons is enhanced if metal particles are incorporated in a TiO2 electrode. Thus, an increase in the anodic photocurrent in the visible region was observed for both the Au and Ag particle dispersed electrodes, which was thought to result from the surface plasmon resonance of the metal particles. 6 Thermally or photocatalytically made cermet materials of silver nanoparticles associated with titania and silica present interesting electrical and optical properties. Electron tunneling between metal islands can allow electrical conductivity, at the same time offering optical transparency, thanks to the low size of the metal particles. 7, 8 The technique of coloring the surface of glasses by applying a coat of silver salts, followed by thermal treatment, has been empirically known for centuries. 9 We now know that color is obtained by surface plasmon frequencies associated with silver nanoparticles. 1, 7 Having all these interesting applications of silvermetal oxide combinations in mind, we have in the present work photocatalytically deposited silver nanoparticles on titania nanoparticle films and have studied them by atomic force microscopy (AFM), UV-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). The novelty of the present work is related with the simple and straightforward preparation conditions for both mesoporous TiO2 films and silver nanoparicle layer, which provide an optically interesting material.