NIRT: Semiconductor Metal Oxide Nanoparticles for Visible Light Photocatalysis

本文系统地研究了二氧化钛纳米粒子作为光催化剂的合成、表征和应用。将研究纳米颗粒在可见光范围内通过调整表面、结构和组成特性来吸收的潜力。具体来说，本提案的多重目标包括利用独特的物理气相沉积工艺获得粒径在1至20 nm之间的TiO2纳米颗粒，并可重复地掺杂各种掺杂剂。这些纳米颗粒将被表征为结构，化学和光电子性质。特别令人感兴趣的是用XPS、UPS和EXAFS表征价带和导带结构。我们还将利用第一性原理计算来获得纳米粒子性质的原子理解。这些理论模型将用于了解纯TiO2纳米粒子和改性TiO2纳米粒子的化学和光化学性质。修饰是指用银、金、铂等贵金属粒子对纳米粒子表面进行选择性修饰。二氧化钛（TiO2）是一种用于环境净化的光催化剂。在吸收光线后，它有助于分解空气和水中的有毒化学物质。然而，TiO2只吸收紫外线。由于大部分太阳光都在可见光范围内，如果能增强其对可见光的吸收，那就更有用了。这一建议描述了一个系统的方法，以增加可见光范围的吸收，通过改变颗粒的大小，组成和表面化学。该提案是响应“纳米尺度科学与工程”（NSF 01-157）的征集而提交的。该奖项由NSF的两个部门联合支持：(i)数学和物理科学（陶瓷项目的材料研究部门）和（ii）工程（化学和运输系统部门）。

This proposal describes a systematic study of the synthesis, characterization, and application of TiO2 nanoparticles as photocatalyst. The potential of the nanoparticles to absorb in the visible range by tailoring the surface, structural and compositional properties will be studied. Specifically, the multifold objectives of this proposal include the utilization of a unique physical vapor deposition process to obtain TiO2 nanoparticles with particle sizes ranging between 1 and 20 nm, and to reproducibly dope the nanoparticles with various dopants. These nanoparticles will be characterized for structural, chemical and optoelectronic properties. Of particular interest is the characterization of the valence band and conduction band structure by XPS, UPS, and EXAFS. We will also utilize first-principles calculations to acquire an atomistic understanding of nanoparticle properties. The theoretical models will be used to develop an understanding of the chemical and photochemical properties of pure and modified TiO2 nanoparticles. Modification involves the selective decoration of nanoparticle surfaces with noble metal particles including Ag, Au, Pt, etc. Titanium dioxide (TiO2) is used as a photocatalyst for environmental cleanup. Upon absorption of light, it helps break down toxic chemicals in air and in water. TiO2, however absorbs only UV light. It would be more useful if its absorption of the visible light can be enhanced since most of the sunlight is in the visible range. This proposal describes a systematic methodology to increase visible range absorption by changing the particle size, composition and surface chemistry.This proposal was submitted in response to the solicitation "Nanoscale Science and Engineering" (NSF 01-157). The award is jointly supported through two directorates at NSF: (i) Mathematical and Physical Sciences (Division of Materials Research in the Ceramics program) and (ii) Engineering (Division of Chemical & Transport Systems).