Roles of the first and second coordination spheres in carbon dioxide reduction catalysts

The efficient conversion of electrical energy and CO₂ to fuels will be important for a flexible and sustainable energy supply in the future. This will require efficient methods for CO₂ recovery and efficient catalysts for CO₂ reduction. To achieve these goals will require an understanding of the contributions of both the first and second coordination spheres of molecules capable of binding CO₂ and transforming them to reduced products. We will describe our most recent work on developing electroactive carrier molecules for selective concentration of CO₂ and the development of electrocatalysts for the reduction of CO₂ to CO. A major obstacle in the development of CO₂ reduction catalysts is achieving reduction beyond CO or formate. Previous work in our laboratories has involved detailed thermodynamic studies of transition metal hydride complexes and formyl complexes, and this information has been used to guide the development stoichiometric reductions of coordinated CO molecules to form formyl complexes using H₂ gas as the reductant at one atm pressure and at room temperature. Further progress in the application of thermodynamic models to the development of catalysts for CO₂ and CO reduction will be described.