Photocatalytic reduction of CO2 in supercritical CO2

INOR 568

David C. Grills,, Kuo-Wei Huang, and Etsuko Fujita, Chemistry Department, Brookhaven National Laboratory, Bldg. 555, Upton, NY 11973
There is an urgent need for new catalytic processes that can efficiently use solar energy to convert carbon dioxide into clean fuels. An exciting possibility is to perform such reactions in supercritical CO2 (scCO2), where the solvent would also be the primary reactant. For homogeneous catalysis this offers many advantages, the main one being that the concentration of CO2 reactant molecules is extremely high (e.g. 20 M at 3000 psi/35 C). We have prepared new catalysts based on previously investigated CO2-to-CO reduction catalysts, applying synthetic functionalizations to render them soluble in scCO2 and also non-coordinating solvents (e.g. hexane). One of these is [Re(dnb)(CO)3]2 (dnb = 4,4'-dinonyl-2,2'-bipyridine). Using a combination of nanosecond time-resolved infrared and UV-vis spectroscopy we have investigated the photochemical reactivity of this complex (and others) in both scCO2 and hexane solution and have found dramatic enhancements in reactivity compared to in coordinating solvents such as THF. This research was supported under contract DE-AC02-98CH10886 with the US Department of Energy.

Catalysis Relevant to Energy and Sustainability
8:30 AM-12:15 PM, Tuesday, March 27, 2007 McCormick Place East -- Room E270, Level 2, Oral

Division of Inorganic Chemistry

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007