Development of High Surface Area Crystalline Semiconductors for Visible Light Driven Photocatalysis

技术综述：利用半导体多相体系将水光催化分解成H2和O2有望成为最简单、最经济的太阳能转换和储存方法之一。限制这些系统实际应用的一个主要因素是缺乏稳定的半导体光催化剂，能够在太阳光谱的可见光范围内以高转换效率进行水的分解。目前提高水的光解效率的大部分努力都集中在致密的块体半导体上，这些半导体由于其低比表面积和显著的电荷复合以及其他问题，如氧化物的带隙宽和硫化物的光化学稳定性低，往往提供较低的转换效率。在这里，通过成分和结构控制来实现带隙工程，模板方法来提高比表面积和催化性能，以及系统的光催化和光物理测量，我们的目标是创造一系列稳定、高效和可见光驱动的纳米多孔光催化剂来分解水。这些光催化剂将是集半导性、高结晶度和可调孔隙率于一体的多功能材料，有望克服已知半导体光催化剂的主要局限性。这些材料的主要优点包括较大的界面表面积，较短的电子-空穴扩散长度到内部界面，以及多种带隙工程路线。拟议中的项目涉及多个研究领域。因此，它将为学生提供极好的培训机会。非技术总结：拟议的研究解决了一个重要的能源和环境问题：使用可再生和无污染的能源。它的目标是开发适合于能源生产和储存的新型多功能材料，例如将可再生太阳能转换为环境友好的氢燃料。它还将提供对控制光催化性能和过程的重要化学和结构因素的基本理解。这将使氢燃料生产的先进材料和工艺的合理合成设计和优化成为可能。加州大学河滨分校的学生群体非常多样化，招收了大量的少数民族学生，加州大学河滨分校和皮耶克？S学院强烈鼓励本科生进行研究。该项目结合了材料合成的多样性和各种表征技术，为学生提供了极好的培训机会。他们在这个项目上的研究经验会对这些学生产生重大影响吗？从事对我们的社会日益重要的研究领域的科学事业。

TECHNICAL SUMMARY:Photocatalytic splitting of water into H2 and O2 using semiconductor-based heterogeneous systems promises to be one of the simplest and most economical methods for solar energy conversion and storage. A major limitation to the practical application of these systems is the lack of stable semiconductor photocatalysts that can carry out the water splitting in the visible region of the solar spectrum with high conversion efficiency. Much of current efforts to improve the efficiency of water photolysis focus on dense bulk semiconductors, and those tend to offer poor conversion efficiency because of their low surface area and significant charge recombination as well as of other problems such as the wide band gaps in oxides and the low photochemical stability of sulfides. Here, through compositional and structural control to achieve band gap engineering, templating approach to enhance surface area and catalytic performance, and systematic photocatalytic and photophysical measurements, we aim to create a family of stable, efficient, and visible light driven nanoporous photocatalysts for water splitting. These photocatalysts will be multi-functional materials that integrate semiconductivity, high crystallinity, and tunable porosity, and will have the potential to overcome the main limitations of known semiconductor photocatalysts. The key advantages offered by these materials include large interfacial surface areas, short electron-hole diffusion lengths to the internal interfaces, and multiple routes for band gap engineering. The proposed project borders on various research areas. It will therefore provide excellent training opportunities for students.NON-TECHNICAL SUMMARY:The proposed research addresses an important energy and environmental issue: the use of renewable and non-polluting energy. It aims to develop new multi-functional materials suitable for energy production and storage such as conversion of renewable solar energy to hydrogen fuel that is environmentally friendly. It will also provide a fundamental understanding about important chemical and structural factors that govern photocatalytic properties and processes. This will allow rational synthetic design and optimization of advanced materials and processes for the hydrogen fuel production. UC Riverside has a very diverse student population with a large enrollment of minority students, and undergraduate research is strongly encouraged at UCR and in the PI?s group. The project combines diversity in materials synthesis and various characterization techniques and provides excellent training opportunities for students. Their research experiences with this project can have a major impact in these students? scientific career in research areas that are of increasing importance to our society.