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

利用太阳光光催化分解水以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。该技术对“太阳能燃料”的生产产生影响，该燃料利用太阳能资源将水或二氧化碳转化为对环境影响较低的价值更高的化学品和燃料。人们越来越认识到，高效的太阳能水分解过程将需要多组分、多功能的光催化系统。这些光催化剂包含半导体光吸收剂、在反应条件下稳定光吸收剂的材料（绝缘体通常用于此功能）和进行化学转化的附着金属电催化剂。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，这些知识将用于形成开发预测性结构-性能关系的基础，这些关系将指导用于高效太阳能水分解的多组分光催化剂的设计。该项目还强调了一系列广泛的教育活动，这些活动建立在首席研究员（PI）的研究基础上，以促进学生参与科学，技术，工程和数学（STEM）学科。该项目将为强调可持续能源主题的大规模开放式在线课程（MOOC）提供新的课程内容。这些活动包括向代表性不足群体的高中生和大学生进行宣传，以及旨在改善利用万维网向学生和公众进行宣传的战略。本项目将重点关注绝缘保护层对太阳能水分解金属-绝缘体-半导体（MIS）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。该项目有两个主要目标：1） 开发一个物理透明的模型，将捕捉MIS光催化剂系统的基本特征，2）在模型的指导下，设计具有最佳几何特性的MIS光催化剂。PI将重点关注一些最有前途的半导体（Si，GaAs和Cu 2 O）及其通过绝缘层（HfO 2和Al 2 O3）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MIS光催化剂的几何结构的原子表征，多组分系统的电子和光学性质的分析，以及严格的测量来评估设备级性能。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.