Oxygen Rich Titania: A Dopant Free, High Temperature Stable, and Visible-Light Active Anatase Photocatalyst
Oxygen Rich Titania: A Dopant Free, High Temperature Stable, and Visible-Light Active Anatase Photocatalyst
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DOI：
10.1002/adfm.201100301
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发表时间：
2011-10-07
影响因子：
19
通讯作者：
Pillai, Suresh C.
中科院分区：
文献类型：
--
作者：
Etacheri, Vinodkumar;Seery, Michael K.;Pillai, Suresh C.
首次报道了在未掺杂的TiO 2中同时存在可见光光催化活性和高达900 ℃的高温稳定性。这些性能是通过热分解过氧二氧化钛复合物（由H2 O2的前体改性形成）原位产生氧气来实现的。含有最高量氧的二氧化钛（16 H2 O2-TiO 2）即使在900 ℃下也保持100%金红石相，而对照样品在该温度下以100%金红石存在。与对照样品和标准光催化剂Degussa P-25相比，相同的组合物分别表现出可见光光催化活性的6倍和2倍增加。在影响光催化活性的各种帕拉中，如带隙变窄、织构性质、晶粒尺寸和晶相稳定性，带隙变窄被确定为负责可见光光催化活性的主要因素。FT-IR、XPS和光致发光（PL）光谱研究表明，Ti-O-Ti键强度的增加和价带（VB）最大值的上移分别决定了Ti-O-Ti的高温稳定性和可见光活性。因此，提出了氧过剩缺陷存在于这些二氧化钛样品负责高温稳定性和增强的可见光催化活性。
The simultaneous existence of visible light photocatalytic activity and high temperature anatase phase stability up to 900 degrees C in undoped TiO2 is reported for the first time. These properties are achieved by the in-situ generation of oxygen through the thermal decomposition of peroxo-titania complex (formed by the precursor modification with H2O2). Titania containing the highest amount of oxygen (16 H2O2-TiO2) retains 100% anatase phase even at 900 degrees C, where as the control sample exists as 100% rutile at this temperature. The same composition exhibits a six-fold and two-fold increase in visible light photocatalytic activities in comparison to the control sample and the standard photocatalyst Degussa P-25 respectively. Among the various para meters affecting the photocatalytic action, such as band gap narrowing, textural properties, crystallite size, and anatase phase stability, band gap narrowing was identified as the major factor responsible for the visible light photocatalytic activity. Increased Ti-O-Ti bond strength and upward shifting of the valence band (VB) maximum, which is responsible for the high temperature stability and visible light activity respectively, are identified from FT-IR, XPS, and photoluminescence (PL) spectroscopic studies. It is therefore proposed that the oxygen excess defects present in these titania samples are responsible for the high temperature stability and enhanced visible light photocatalytic activities.