Maximizing efficiency in solar water splitting by engineering interfaces in hybrid photo-catalysts

利用太阳光光催化分解水产生丰富而廉价的氢燃料是科学家和工程师面临的重要技术挑战。这项技术对“太阳能燃料”的生产产生了影响，这种燃料利用太阳能资源将水或二氧化碳转化为价值更高的化学品和对环境影响较小的燃料。人们越来越认识到，高效的太阳能分解水过程将需要多组分、多功能的光催化系统。这些光催化剂包含半导体吸光器，一种在反应条件下稳定吸光器的材料(绝缘体通常用于此功能)，以及附着的执行化学转化的金属电催化剂。在这个项目中，基本的理解将导致这些多功能光催化剂的不同成分如何影响这些系统的性能。最终，这些知识将被用来形成开发预测性结构-性能关系的基础，这些关系将指导高效太阳能水分解的多组份光催化剂的设计。该项目还强调在首席调查员(PI)研究的基础上开展广泛的教育活动，以促进学生参与科学、技术、工程和数学(STEM)学科。该项目将为一个大规模的开放式在线课程(MOOC)提供新的课程内容，强调可持续能源主题。这些活动包括向任职人数不足群体的高中生和本科生进行外联，以及旨在改进利用万维网接触学生和普通公众的战略。本项目将致力于了解绝缘保护层对金属-绝缘体-半导体(MIS)太阳能分解水光催化剂系统整体性能的影响。该项目的目的是确定影响性能的保护层的基本特性，并调整这些特性以设计具有最小结损的MIS光催化剂。该项目有两个核心目标：1)开发一个物理透明的模型，以捕捉MIS光催化剂体系的基本特征；2)在该模型的指导下，设计出具有最佳几何特性的MIS光催化剂。PI将集中在一些最有前途的半导体(Si、GaAs和Cu2O)以及它们通过绝缘层(HfO2和Al_2O_3)与析氧反应(OER)电催化剂(Ni、Ru和Ir)的耦合。该项目将使用表征技术，包括对管理信息系统光催化剂几何结构的原子化表征，对多组分系统的电子和光学性质的分析，以及评估设备级性能的严格测量。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Photocatalytic splitting of water using sunlight to create abundant and inexpensive hydrogen fuel is an important technical challenge for scientists and engineers. This technology has impact for the production of "solar fuels" that uses the resource of solar energy to convert water or carbon dioxide into higher valued chemicals and fuels with a lower environmental impact. It is becoming increasingly recognized that high efficiency solar water splitting processes will require multi-component, multi-functional photo-catalytic systems. These photocatalysts contain a semiconductor light absorber, a material that stabilizes the light absorber under the reactions conditions (insulators are often used for this function) and attached metal electrocatalysts that perform chemical transformations. In this project, fundamental understanding will result on how different components of these multi-functional photo-catalysts impact the performance of these systems. Ultimately, the knowledge will be used to form the foundation for developing predictive structure-performance relationships that would guide the design of the multi-component photocatalysts for efficient solar water splitting. The project also emphasizes a wide array of educational activities that build upon the Principal Investigator's (PI) research to promote engagement of students in science, technology, engineering and mathematics (STEM) disciplines. The project will result in new curriculum content for a massive open online course (MOOC) emphasizing sustainable energy topics. These activities include outreach to high school and undergraduate students from underrepresented groups, as well as strategies aimed at improving the utilization of the World Wide Web in reaching students and the general public. This project will focus on fundamental understanding about the influence of insulating protective layers on the overall performance of metal-insulator-semiconductor (MIS) photocatalyst system for solar water splitting. The aim of the project is to identify the fundamental characteristics of the protective layers that impact the performance and tune these characteristics to design MIS photocatalyst with minimal junction losses. The project has two central objectives: 1) Developing a physically transparent model that will capture the essential features of the MIS photocatalyst systems, 2) Guided by the model, design MIS photocatalysts with optimal geometric characteristics. The PI will focus on some of the most promising semiconductors (Si, GaAs, and Cu2O) and their coupling to oxygen evolution reaction (OER) electrocatalysts (Ni, Ru, and Ir) through the insulating layers (HfO2 and Al2O3). The project will use characterization techniques that include atomistic characterization of the geometric structure of the MIS photocatalysts, analysis of electronic and optical properties of the multicomponent systems as well as rigorous measurements to assess the device-level performance.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.