DESIGN, SYNTHESIS AND STUDY OF MULTI-COMPONENT AND INTEGRATED SYSTEMS FOR LIGHT-DRIVEN HYDROGEN GENERATION
The research focussed on fundamental problems in the conversion of light to stored chemical energy. Specifically, work was completed on the design, synthesis and study of multi-component super- and supramolecular systems for photoinduced charge separation, one of the key steps in artificial photosynthesis, and on the use of these and related systems for the photochemical generation of H2 from water. At the center of these systems are chromophores comprised of square planar coordinated Pt(II) ions with arylacetylide and either diimine or terpyridyl ligands. Previous work had shown that the chromophores are photoluminescent in fluid solution with long-lived metal-to-ligand charge transfer (3MLCT) excited states that are necessarily directional. An advance which set the stage for a number of proposed studies was the light-driven production of hydrogen from water using a Pt(terpyridyl)(arylacetylide)+ chromophore and a sacrificial electron donor. The reaction is catalytic and appears to rival previously reported ruthenium bipyridyl systems in terms of H2 production. Variation of system components and mechanistic studies were conducted to understand better the individual steps in the overall process and how to improve its efficiency. Success with light driven H2 generation was employed as a key probe as new systems were constructed consisting of triads for photoinduced charge separation placed in close proximity to the H2 generating catalyst - a Pt colloid - through direct linkage or supramolecular interactions with the polymer used to stabilize the colloid. In order to prepare new donor-chromophore-acceptor (D-C-A) triads and associated D-C and C-A dyads, new ligands were synthesized having functional groups for different coupling reactions such as simple amide formation and Pd-catalyzed coupling. In these systems, the donor was attached to the arylacetylide ligands and the acceptor was linked to the diimine or terpyridyl chelate. Research under the contract proved successful in the development of synthetic methodologies to make multi-component systems designed so as to maintain electronic communication between components held in a defined spatial arrangement. Systems effective for light driven H2 generation were examined by photophysical methods including transient absorption spectroscopy to observe charge-separated states and chart their dynamics. Quantum yields for hydrogen production were also measured. Additional studies examined the effectiveness of these systems for H2 generation and involved the development of new catalysts and systems based thereon. From these studies, a better understanding of initial steps in the light driven generation of hydrogen were obtained.
- Research Organization:
- Univ. of Rochester, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- FG02-90ER14125
- OSTI ID:
- 1046034
- Report Number(s):
- DOE/ER14125-Final; TRN: US201215%%381
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
13 HYDRO ENERGY
14 SOLAR ENERGY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
AMIDES
BINDING ENERGY
CATALYSTS
COLLOIDS
COMMUNICATIONS
EFFICIENCY
ELECTRONS
EXCITED STATES
FUNCTIONALS
HYDROGEN
HYDROGEN PRODUCTION
PHOTOSYNTHESIS
POLYMERS
PROBES
PRODUCTION
RUTHENIUM
SYNTHESIS
TRANSIENTS
VALENCE
solar energy conversion
artificial photosynthesis
photogeneration of hydrogen
metal complex photochemistry
photoinduced charge separation
solar hydrogen