CAREER: Rational Design, Synthesis and Understanding of Heteronanostructures as Photoelectrodes for Water Splitting

技术概述：先进的能量转换装置的性能，包括太阳能水分解装置的性能，最终与纳米级电极材料的设计有关。目前在这一领域的研究受到现有材料的固有特性和发现新材料进展缓慢的限制。在材料研究部固态与材料化学项目的支持下，该提案将通过设计、制备和理解一类新的纳米基材料来解决这一挑战。该项目将建立在PI过去在制造具有异质界面的纳米结构方面的成功基础上，通过研究包括TiSi2纳米网在内的组合，TiSi2纳米网是PI实验室发现的独特的二维纳米结构，具有适当的高表面积和高导电性，以及各种氧化物半导体，如TiO2， WO3和Fe2O3。具体来说，PI旨在解决这些氧化物中电荷扩散不良的问题。改进的电荷收集将减少光产生电荷的不希望的积累，从而提高光子到电子的转换效率。该研究将集中于了解纳米结构的电子特性如何受到其形态和组成的影响。采用的实验技术包括化学气相沉积（用于制备TiSi2纳米网）、原子层沉积（用于纳米网周围的氧化物半导体的保形涂层）、各种电化学方法和大量的结构表征程序。这些实验将提供有关纳米结构的结晶度、电子性质和化学性质的信息，这些信息不仅对水分解至关重要，而且对许多相关的能量转换和存储过程也至关重要，其中电荷传输起着重要作用。非技术总结：收集太阳能并通过分解水直接使用它来生产氢气的能力有可能满足能源需求，而不会对环境产生负面影响。由于缺乏合适的材料，这项研究目前进展缓慢。拟议中的项目将引入一种全新的设计，可能会显著推进该领域的发展，并使太阳能水分解成为现实。这种设计的关键是PI实验室发现的一种独特的二维纳米结构。当与氧化物半导体结合时，纳米网可以提供专用的电荷传输途径，从而实现高效的太阳能水分解。一个旨在传播清洁能源技术信息的综合性新教育项目将加强研究工作。拓展项目将利用波士顿学院橄榄球比赛的受欢迎程度。PI团队将参加吸引包括K-12学生在内的大批校友和参观者的FanFest活动，展示清洁能源的生产和使用方法。还将设立一个暑期项目，每年从当地高中邀请一到两名科学教师对提议的主题进行研究，并获得实践经验，他们将能够与学生分享。

TECHNICAL SUMMARY:The performance of advanced energy conversion devices, including that for solar water splitting, is ultimately connected to the design of the electrode materials at the nanoscale. Current research in this area is limited by how much one can tailor the intrinsic properties of existing materials and the slow progress in discovering novel materials. Supported by the Solid State and Materials Chemistry program within the Division of Materials Research, this proposal will address the challenge by designing, preparing and understanding a new class of nanonet-based materials. The project will build on the PI's past success in making nanostructures with heterogeneous interfaces by studying combinations that include TiSi2 nanonets, which are unique two-dimensional nanostructures discovered by the PI's lab that offer suitably high surface areas and high conductivities, and a variety of oxide semiconductors such as TiO2, WO3 and Fe2O3. Specifically, the PI aims at solving the problems of poor charge diffusion within these oxides. The improved charge collection will reduce the undesired accumulation of photogenerated charges and thereby increase the photon-to-electron-conversion efficiencies. The study will focus on understanding how the electronic properties of nanostructures are influenced by their morphologies and compositions. Experimental techniques to be employed include chemical vapor deposition (for the creation of TiSi2 nanonets), atomic layer deposition (for the conformal coating of oxide semiconductors around the nanonets), various electrochemical methods, and a host of structural characterization procedures. These experiments will produce information on the crystallinity, the electronic property and the chemical property of the nanostructures, which will be essential to not only water splitting but also a number of related energy conversion and storage processes where charge transport plays an important role.NON-TECHNICAL SUMMARY:The ability to harvest solar energy and use it directly to produce hydrogen by splitting water has the potential to meet the energy needs without a negative impact on the environment. Due to the lack of suitable materials, this research is currently progressing at a slow pace. The proposed project will introduce a fundamentally new design that may advance the field significantly and make solar water splitting practical. The key to this design is a unique two-dimensional nanonet structure the PI's lab has discovered. When combined with oxide semiconductors, the nanonets can provide a dedicated charge transport pathway that should enable high-efficiency solar water splitting. The research efforts will be augmented by a fully integrated novel education program that aims at disseminating information on clean energy technology. The outreach program will take advantage of the popularity of Boston College's football games. The PI's team will participate in the FanFest event, which attracts a large number of alumni and visitors including K-12 students, by demonstrating how clean energy can be produced and used. A summer program will also be established to invite one to two science teachers each year from local high schools to conduct research on the proposed topics and gain hands-on experience which they will be able to share with their students.