(566a) (Photo-)Electro-Catalytic Fuel Production

The electrochemical reduction of carbon dioxide is an enabling technology for the development of carbon-neutral, drop-in replacement fuels and chemicals from solar and other carbon free energy sources. We consider catalysts for the reduction of CO₂ to CO.  We performed an extensive set of density functional theory calculations for the elementary mechanism of CO₂ reduction including the potential dependence of the energy of all intermediate steps in the process. On this basis we establish an understanding of trends in reactivity for a class of transition metals.  We identify descriptors of reactivity and establish a volcano relationship between overpotential and descriptors. We extend the density functional theory calculations to include two-component transition metal alloys, a model of the active site in the the CODH enzyme and transition metal sulfide clusters in the form of cubanes. We show why the enzyme has low overpotential and how similar results can, in principle, be obtained by alloying.