The Influence of Charged Interfaces on the Enhanced Photochemical Reactivity of Composites

带电界面对增强复合材料光化学反应活性的影响

• 批准号: 1206656
• 负责人: Gregory Rohrer
• 金额: $ 63.96万
• 依托单位: Carnegie-Mellon University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1206656&HistoricalAwards=false
• 关键词: Influence; Charged; Interfaces; Enhanced; Photochemical

NON-TECHNICAL DESCRIPTION: Hydrogen is an attractive fuel for energy production because it has a high energy density and its combustion generates only water vapor, leaving no carbon bearing or radioactive by-products. However, unlike fossil or nuclear fuels, it cannot be mined from the earth; hydrogen must be synthesized. Photolysis, or light-driven water-splitting, is a promising renewable method to synthesize hydrogen. However, the best currently available processes are inefficient and, because of this, they are not competitive with conventional fuel sources. One of the fundamental problems is that no single material possesses the combination of properties needed to efficiently split water. This project is based on the idea that a composite, that combines materials with synergistic properties, will be able to catalyze water photolysis more efficiently and currently available materials.TECHNICAL DETAILS: This project aims to test the hypothesis that by controlling charges at interfaces in oxide heterostructures, it is possible to build in mechanisms to separate photogenerated electron-hole pairs and thereby increase the efficiency of photolysis (water-splitting). The project builds upon recent discoveries of the composite catalyst effect for enhanced photochemical reactivity and has the ultimate goal of developing a sustainable fuel source. The hypothesis is being tested by studying a combination of planar oxide heterostructures, ideal for controlled measurements, and heterostructured oxide powders that would be required for any practical implementation. Fe2O3 and TiO2 films will be supported on a variety of ABO3-type substrates (for example, LaAlO3, SrTiO3, BaTiO3, PbTiO3, BiFeO3, and FeTiO3); by choosing the appropriate phase and orientation, it is possible to control the spectral range of absorption, the carrier type, and whether or not there is a potential difference at the interface deriving from ferroelectricity, polar terminations. The effects of band offsets will also be explored in compounds in the pseudo-binary Cu2O-Fe2O3 system. Cross sectional scanning potential (Kelvin probe) microscopy is being used to map potential differences at the buried interfaces and these measurements are being compared to photoelectrochemical measures of reactivity and efficiency. Experiments are also being conducted to examine the effects of length scale on the properties of the heterostructures. The research will be an integral part of the education of graduate and undergraduate Materials Science and Engineering students.

非技术描述：氢气是一种有吸引力的能源生产燃料，因为它具有高能量密度，其燃烧仅产生水蒸气，不会留下含碳或放射性副产物。 然而，与化石燃料或核燃料不同，它不能从地球上开采;氢必须合成。光解，或光驱动水裂解，是一种有前途的可再生制氢方法。 然而，目前最好的工艺效率低下，因此，它们与传统燃料源相比没有竞争力。 其中一个基本问题是，没有一种单一的材料具有有效分解水所需的特性组合。 该项目基于一种复合材料的想法，这种复合材料将具有协同性能的材料结合在一起，能够更有效地催化水的光解，并且是目前可用的材料。本项目旨在验证通过控制氧化物异质结构界面处的电荷，可以建立分离光生电子-空穴对的机制，从而提高光解（水分解）的效率。 该项目建立在最近发现的增强光化学反应性的复合催化剂效应的基础上，最终目标是开发一种可持续的燃料来源。 这一假设正在通过研究平面氧化物异质结构的组合进行测试，这是控制测量的理想选择，而异质结构氧化物粉末则是任何实际实施所需的。 Fe 2 O3和TiO 2薄膜将被支撑在各种ABO 3型衬底上（例如，LaAlO 3、SrTiO 3、BaTiO 3、PbTiO 3、BiFeO 3和FeTiO 3）;通过选择适当的相和取向，可以控制吸收的光谱范围、载流子类型以及界面处是否存在由铁电性、极性终端引起的电势差。 带偏移的影响，也将探讨在伪二元Cu 2 O-Fe 2 O3系统的化合物。 横截面扫描电位（开尔文探针）显微镜被用来映射电位差在掩埋接口和这些测量正在进行比较的反应性和效率的光电化学措施。 实验也正在进行研究的异质结构的性能上的长度尺度的影响。 这项研究将成为材料科学与工程专业研究生和本科生教育的一个组成部分。