Palladium-gold catalyst for the electrochemical reduction of CO₂ to C₁-C₅ hydrocarbons

Copper is a unique electrocatalyst for CO₂ reduction, since it is one of the few catalysts able to produce methane, ethylene and ethane from CO₂ with decent faradaic efficiencies. Here we report on the design and synthesis of a new non-copper-containing catalyst able to reduce CO₂ to C₁ to C₅ hydrocarbons. This catalyst was designed by combining a metal that binds CO strongly, Pd, with a metal that binds CO weakly, Au, in an attempt to tune the binding energy of CO. We show that a mixture of C₁-C₅ hydrocarbons and soluble products are produced from an onset potential of -0.8 V_RHE. We propose that the higher hydrocarbons are formed via a polymerization of -CH₂ groups adsorbed on the catalyst surface.