Collaborative Research: SusChEM: The Design, Chemistry and Study of Systems for Making Solar Hydrogen

This project is supported by the Chemical Catalysis Program of the National Science Foundation and involves a four-way collaboration between Professors David McCamant and Richard Eisenberg of the University of Rochester, and Michael Detty and David Watson of the University at Buffalo. The goal of the research is to develop a new fundamental understanding of chemical systems that can produce hydrogen by splitting water molecules into hydrogen (H2) and oxygen (O2) gases using solar energy. For the capture and storage of solar energy, water splitting is the ideal reaction. The recombination of H2 and O2 to produce water is a convenient and clean source of energy upon demand. This research project involves making new molecules to facilitate the water splitting reaction in the Eisenberg lab, making new dye molecules to absorb visible light from the sun in the Detty lab, studying the fast photochemical reactions that occur after those molecules absorb light in the McCamant lab, and making new nanoparticle semiconductor systems as scaffolds for solar hydrogen production in the Watson lab. Each of the investigators brings to the collaborative research different perspectives and skills that are leading to a significant new understanding of a fundamentally challenging problem in solar energy conversion. In outreach efforts, the scientists supported by this grant are working with local elementary schools in Rochester and Buffalo, New York, to develop energy-related science modules that can inspire the next generation of scientists. This research, funded by the Chemical Catalysis Program of the NSF, consists of the design and study of systems for the light-driven generation of H2 from aqueous protons, and associated photochemical and photophysical investigations to fully understand this transformation. The reaction corresponds to the reductive side of water splitting, 2H+ + 2e- -> H2, which is the key reaction in artificial photosynthesis and the conversion of light into stored chemical potential energy. While seemingly simple, the detailed mechanism of the light-driven generation of H2 is complex, particularly in an integrated system. In this project, the researchers focus on three specific research goals: the synthesis and characterization of new chromophores; the design and development of new catalysts containing common metal ions that are effective in photochemical systems for light-driven proton reduction in aqueous media; and the construction of new integrated proton reduction systems based on semiconductor materials such as SrTiO3, as structural scaffolds and on photocathode materials such as CuAlO2, to eliminate the need for chemical sources of electrons for proton reduction. Each of these areas are being explored with cutting-edge femtosecond time-resolved spectroscopy capable of probing dynamics involving initial light-driven events, longer duration transient absorption methods to follow later electron transfers and steady-state methods that can establish mechanisms of catalysis, molecular and interfacial structures, and long-term system stability. The scientists supported by this grant are also working with local elementary schools in Rochester and Buffalo, New York, to develop energy related science modules that can inspire the next generation of scientists.