Ag nanoclusters on anatase single crystal TiO2 surfaces: the role of electronic structure in the enhanced photoactivity of Ag dosed TiO2 nanoparticles

锐钛矿单晶 TiO2 表面上的银纳米簇：电子结构在增强掺银 TiO2 纳米颗粒光活性中的作用

• 批准号: EP/J015075/1
• 负责人: Andrew THOMAS
• 金额: $ 0.66万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FJ015075%2F1
• 关键词: Ag; nanoclusters; anatase; single; crystal

Titanium dioxide (Titania/TiO2) is usually used in the form of a white powder. It exists in three different structures, rutile, anatase and brookite. It has uses which range from a white pigment (used in mayonnaise and toothpaste as well as paints) to generating electricity from sunlight where it is "activated" with a dye. Its main advantages are that it is not toxic and cheap to produce on a large scale. In the 1970's it was found that titania in the presence of ultra violet light could also be used to split water into hydrogen and oxygen, which could then potentially be used as fuels. However despite much active research the full potential in this area has not been realised. Related to this photocatalytic property however, titania has been used to breakdown organic chemicals and also kill bacteria in waste water. It is also this property which is used in self-cleaning windows which have a thin film of titania on them. Many of these applications use the titania consisting of particles a few tens or hundreds of nanometres in size, which forces the titania to adopt the anatase structure.Recently it was found that adding nanometre sized clusters of silver to the nanoparticles of titania dramatically improved their photocatalytic activity. However it is not known why this is the case. The electronic structure (i.e. the states where electrons are located) in the bonds between the titanium and oxygen (the valence band) is thought to be key to the photocatalytic activity of titania. In this work we want to look in detail at these valence electrons using a synchrotron radiation source in Sweden. Synchrotron radiation allows us to tune the energy with which we probe our samples, which in turn allows us to map the contributions of the various elements to the valence band. The work requires relatively low energy light which is not currently available in the UK. The aim is to understand how silver modifies the electronic structure of the titania and correlate this to the increased photocatalytic activity. By understanding how this system works we can use the minimum amount of silver to enhance the activity of the catalyst and therefore keep the costs of developing these catalysts down. We may also help other researchers identify other metals or materials which can increase the efficiency of the catalysts further.

二氧化钛（二氧化钛/TiO 2）通常以白色粉末的形式使用。它存在于三种不同的结构中，金红石、金红石和板钛矿。它的用途从白色颜料（用于蛋黄酱、牙膏和油漆）到用染料“激活”太阳能发电。它的主要优点是无毒，大规模生产便宜。在20世纪70年代，人们发现二氧化钛在紫外光的存在下也可以用来将水分解成氢和氧，然后可以潜在地用作燃料。然而，尽管进行了大量积极的研究，但这一领域的全部潜力尚未实现。然而，与这种光催化性能相关的是，二氧化钛已被用于分解有机化学品，并杀死废水中的细菌。这种特性也被用于自清洁窗户，窗户上有一层氧化钛薄膜。这些应用中的许多都是使用由几十或几百纳米大小的颗粒组成的二氧化钛，这迫使二氧化钛采用纳米结构。最近发现，在二氧化钛纳米颗粒中加入纳米尺寸的银团簇可以显著提高其光催化活性。然而，不知道为什么会出现这种情况。钛和氧之间的键（价带）中的电子结构（即电子所处的状态）被认为是二氧化钛的光催化活性的关键。在这项工作中，我们想看看在这些价电子使用同步辐射源在瑞典的细节。同步辐射使我们能够调整探测样品的能量，这反过来又使我们能够映射各种元素对价带的贡献。这项工作需要相对较低的能量光，这是目前在英国无法获得的。目的是了解银如何改变二氧化钛的电子结构，并将其与增加的光催化活性相关联。通过了解该系统如何工作，我们可以使用最少量的银来提高催化剂的活性，从而降低开发这些催化剂的成本。我们还可以帮助其他研究人员确定其他金属或材料，以进一步提高催化剂的效率。