NIRT: Semiconductor Metal Oxide Nanoparticles for Visible Light Photocatalysis

该提案描述了一个系统的研究的合成，表征和应用的二氧化钛纳米粒子作为光催化剂。 将研究纳米颗粒通过调整表面、结构和组成特性在可见光范围内吸收的潜力。 具体而言，该提议的多重目标包括利用独特的物理气相沉积工艺来获得粒径范围在1和20 nm之间的TiO 2纳米颗粒，以及用各种掺杂剂可重复地掺杂纳米颗粒。这些纳米粒子将被表征为结构，化学和光电特性。 特别感兴趣的是通过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。 理论模型将用于开发纯和改性的二氧化钛纳米粒子的化学和光化学性质的理解。 改性涉及用贵金属颗粒（包括Ag、Au、Pt等）选择性地修饰纳米颗粒表面。 二氧化钛（TiO 2）被用作环境净化的光催化剂。 在吸收光后，它有助于分解空气和水中的有毒化学物质。 然而，TiO 2仅吸收UV光。 如果它对可见光的吸收可以增强，这将是更有用的，因为大多数阳光都在可见光范围内。 该提案描述了一种通过改变颗粒尺寸、组成和表面化学来增加可见光范围吸收的系统方法。该提案是应“纳米科学与工程”（NSF 01-157）的征集而提交的。该奖项由NSF的两个董事会共同支持：（i）数学和物理科学（陶瓷计划材料研究部）和（ii）工程（化学运输系统部）。

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).