The electrochemical reduction of CO 2 into reduced carbon compounds is a compelling strategy to sustainably synthesize fuels and commodity chemicals using renewable energy sources. Although promising post-transition metal electrocatalysts have been developed from monometallic thin films, limited effort has been dedicated to the use of trimetallic alloys for CO 2 electrocatalysis. In this work, we have explored the electrocatalytic effect of alloying Sn, Pb, and Bi, which are all reported as being individually active catalysts for CO 2 reduction to different extents. It is demonstrated that the well-known soldering alloy Bi 50 Sn 22 Pb 28 (Rose's metal = RM) promotes the conversion of CO 2 to CO in MeCN electrolyte containing millimolar concentrations of the ionic liquid additive [BMIM]OTf. Planar RM electrocatalysts evolve CO with Faradaic efficiencies as high as 95% with average geometric current densities of j tot = 3−10 mA/cm 2 . XPS analysis shows evidence for the accumulation of metal oxides on the RM surface following CO 2 electrocatalysis, which may influence the activity of the alloy.