Visible-Range Sunlight Drives CO2 Reduction Process for Cheaper Syngas


Background: The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing a method for photocatalytically reducing CO2 to CO at unprecedented reaction rates. Technology Description: In a reverse water gas shift reaction CO2 is reduced to water and carbon monoxide (CO). The CO generated by this reaction is a key component in synthesis gas also called syngas which can be converted to liquid fuels using existing technologies. This endothermic reaction must be driven by outside energy. The ability to harness sunlight reduces fossil energy inputs improves overall efficiency and makes the process industrially relevant. UW–Madison researchers have developed a new method of reducing CO2 to CO via a reverse water gas shift reaction using visible solar light. The reaction produces a syngas mixture which can be further converted to liquid fuels. In this process CO2 (which can be obtained from many industrial processes) is contacted with a plasmonic catalyst in the presence of hydrogen. The catalyst is exposed to visible-range sunlight so that it undergoes an optical phenomenon called surface plasmon resonance which causes metal electrons to oscillate in a certain way and accelerates the rate of CO2 reduction. The process results in CO2 being reduced to water and CO that can be collected for downstream products. Applications: Cost-effective production of syngas and other downstream products like formic acid and hydrocarbons.


1) Utilizes solar energy 2) Achieves light efficiency of at least four percent 3) Surface plasmon resonance in the catalyst increases rates of CO2 reduction by a factor of five or more 4) Much more efficient than catalysts that only operate in the UV range

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