In this project, the researchers will investigate a relatively new class of materials known as metal-organic frameworks (MOFs) as to their suitability as catalysts for the production of hydrogen as a sustainable fuel from sunlight and water. The specific goals of this project are to examine how placement of the photosensitizer and catalytic centers within zirconium-based MOFs influence both the mechanism by which photocatalysis occurs and the corresponding efficiency of the photocatalytic reaction. More broadly, the research will create a structural model for future studies of real-time structure-function correlations for other photoactive materials, impacting broadly on fields such as photocatalysis, optoelectronic devices, and solar energy conversion technologies. In turn, this research will help identify efficient materials for an eventual carbon-neutral, economically-viable fuel industry driven by solar energy. The project will include training and mentoring of graduate and undergraduate students in photocatalysis research, which will strengthen the U.S. pipeline of science-educated students prepared to tackle next-generation problems in materials science, sustainable chemistry, and energy science.
The project focuses on real-time spectroscopic studies of MOFs in which the photosensitizer and catalytic center are well-organized within MOFs. The PIs have identified highly robust Zr-based MOFs that contain coordinately unsaturated Zr6-clusters as the structural prototype. Structural topology will be used as a guide to insert both the photosensitizer and catalyst into the MOF structure, in a controllable, step-wise fashion, to generate new hybrid MOF photocatalysts. The charge separation and structural dynamics of the hybrid materials will be investigated using time resolved optical and X-ray absorption spectroscopies as well as in situ X-ray absorption spectroscopy. These techniques will be used to establish a direct correlation between the structure of the hybrid catalysts and their catalytic efficiency for hydrogen production. The proposed research will be integrated with educational activities that will provide opportunities for undergraduate students, and encourage women to pursue research and science careers. The graduate and undergraduate students working on the project will receive interdisciplinary training in the fields of materials chemistry, physical chemistry, and solar energy science.
