8 electrons) are extremely limited. New approaches to hydride and hydrogen atom transfer need
to be developed. Theoretical studies of mechanisms, structures of intermediates, and transition
states are needed to augment experimental work. New theoretical treatments are also needed to
handle multi-body and strongly coupled electron-nuclear events.
Catalytic Reactions at Interfaces and Surfaces in Order to Understand These Reactions
at a Molecular Level. Catalytic mechanisms must be understood at a molecular level when the
catalyst is present at an interface or on a surface. This understanding should include the
development of both catalysts and techniques that permit the detection and study of all the
intermediates relevant to the catalytic process and their reaction sequence, kinetics, and
energetics.
Synthesis of Robust Functional Catalysts that Mimic Biological Processes. A
combination of techniques (ranging from X-ray crystallography and magnetic resonance
spectroscopies to genetic engineering) can elucidate the structure and dynamics of the
intermediates of catalytic reactions occurring at redox centers of key enzymes, such as
Photosystem II, involved in solar energy conversion. This knowledge is necessary to identify the
precise molecular mechanisms of these biological processes. Guided by this knowledge,
effective catalysts for water oxidation and carbon dioxide reduction must be synthesized, tested,
and optimized. Targets include polynuclear metal systems and particularly metals that can
replace high-cost noble metals as catalysts.
RELEVANCE AND POTENTIAL IMPACT
Practical solar fuel formation requires construction of currently unknown catalyst systems to
form hydrogen and oxygen from water and to efficiently reduce carbon dioxide from the air. The
development of water oxidation and carbon dioxide reduction catalysts will provide non-
polluting fuels, namely hydrogen and hydrocarbons, from readily available feedstocks. Burning
hydrogen results only in the production of water, while burning hydrocarbon fuels made from
carbon dioxide provides a closed cycle that does not increase the carbon burden in the
atmosphere.