reduction of carbon dioxide and carbon monoxide using bifunctional Alloys
Hansen, H. A. et al. Bifunctional alloys for the electroreduction of CO2 and CO. Physical Chemistry Chemical Physics, 18, 9194-9201, DOI: 10.1039/C5CP07717F (2016).
Successful reduction of CO2 to fuels, such as methane or higher hydrocarbons, can only be accomplished through the discovery of catalysts that do not suffer from high overpotentials, low current densities, poor selectivity or durability. In addition, detailed understanding of the mechanisms of these reactions is needed.
Both experimental and theoretical work suggest that production of hydrocarbons from CO2 involves the formation and reduction of intermediates, such as CO, CO*, CHO*.
This theoretical work explores the possibility of lowering the limiting potential for the formation of reaction intermediates through alloying. For example, alloying coinage metals (e.g., Ag, Au, and Cu) with elements such as Zn, Cd, Ga, In and Sn, or Pt with Fe or Co. The research team performed density functional screening of alloys with A3B composition. They focused on (211)/(111) facets of these alloys.
The conclusion from this study was that theory can identify alloy compositions that allow for the increased activity for CO2 and CO reduction. However, such alloys are also predicted to be prone to electrochemical corrosion or segregation that would destroy the bifunctional active sites. Therefore strategies to improve stability would need to be developed to fully realize the potential applications for such materials.