First principles guided design of borohydride oxidation electrocatalysts

The application of density functional theory (DFT) methods to investigate energetics of surface processes is an essential tool in heterogeneous catalysis research. Application of DFT methods to electrocatalytic systems introduces additional challenges in developing appropriate model systems. A series of approaches are now available to approximate the effects of charge separation and solvation at the electrode-electrolyte interface on elementary reaction energetics. The use of DFT methods as the primary driving force in mechanism elucidation and electrode design will be demonstrated through application to direct borohydride fuel cell anode design. Direct Borohydride Fuel Cells (DBFCs) have the potential to generate high power densities for use in portable power applications. Current applications are limited by the lack of an effective anode electrocatalyst. The complexity of the 8 electron oxidation reaction challenges experimental mechanism determination and limits the rational design of improved electrocatalysts. We used DFT methods to examine the mechanism of borohydride electro-oxidation over the Au(111) surface, a catalyst with low activity, and the Pt(111) surface, a catalyst with low selectivity. Key energetic parameters for dictating activity and selectivity were evaluated for pure and bimetallic electrocatalysts. Au-Cu alloys are predicted to be encouraging for improved performance. Electrokinetic studies are used to corroborate mechanisms and realize predicted binary metal performance proposed by computational work.