CAREER: Developing Novel Biomimetic Heterostructured Ceramics for Water Splitting

Suny At Stony Brook, Stony Brook NY

Investigators

Abstract

NON-TECHICAL DESCRIPTION: Development of new methods for converting solar energy into fuels offers tremendous potential to address both sustainable energy and environmental issues. Producing hydrogen from water using sunlight and light-activated materials is an attractive strategy for solar energy storage and conversion. Despite tremendous progress in the design of new materials, the efficiency of this conversion process is still very low. To address this challenge, this project focuses on overcoming several bottlenecks in materials science and chemistry by adopting a process that occurs naturally in biological systems. The experimental strategy uses novel composite materials, where oxygen and hydrogen are produced on different semiconductors coupled together. This approach, inspired by natural photosynthesis, is called the Z-scheme. TECHNICAL DESCRIPTION: Previous studies employing a Z-scheme for water splitting typically involved the use of two different semiconductor powders in aqueous solutions, which are coupled by redox agents that act as an electron shuttle between the two components. In this work, Orlov's group is using an all solid-state Z-scheme system which has the potential advantage of using individual components that are optimized for only one of the water splitting half reactions (water oxidation or water reduction), and placing them in intimate contact to promote charge transfer between them. By eliminating the need for a redox shuttle, an all solid-state Z-scheme photocatalyst offers the potential of higher efficiency and is more amenable to fundamental investigations of atomic and electronic structure using surface science probes. Specifically, the experimental design involves working with systems that combine two metal oxide materials that act as oxidation and reduction photocatalysts that can be prepared both as a powder and as a thin film with well-defined surface properties. The transformational aspect of this research is in development of a new class of composite systems with potentially higher activity for hydrogen production as compared to any single catalyst. The development and characterization of the model photocatalyst presents many challenges, which this project addresses by an interdisciplinary approach with broad range of characterization techniques, solid-state synthesis, activity characterization and surface science tools. The project-related activities also expand the curriculum and cutting edge research opportunities in materials science and engineering with significant inclusion of underrepresented students. In addition, the educational part of the project introduces high school students and teachers to nanotechnology research using their newly developed photocatalytic testing kit. The project also includes several other innovative elements, such as the development of on-line educational tools designed to teach students the concepts of sustainable materials.