An electrode that has a film adsorbed to its surface by reductive electropolymerization of (vbpy)Re(CO).sub.3 Cl (4-vinyl-4'-methyl-2,2'-bipyridine tricarbonylchlororhenium(I)) or its acetonitrile analogue, [(vbpy)Re(CO).sub.3 (MeCN)].sup.+ (4-vinyl-4'-methyl-2,2'-bipyridine tricarbonylacetonitrile rhenium (I)). The poly (vbpy)Re(CO).sub.3 Cl or poly-[(vbpy)Re(CO).sub.3 (MeCN)].sup.+ adsorbed onto the electrode, acts as a catalyst for CO.sub.2 reduction to CO. Stability and the reactivity of the polymer film may be increased by co-reductive electropolymeriaztion of either of the aforesaid Re complexes with [(bpy).sub.2 Ru(vpy).sub.2.sup.2+ ](bis(4-vinyl-pyridine)bis(2,2'-bipyridine) ruthenium (II)) (vpy is 4-vinylpyridine). A bilayer film assembly consisting of poly-[(bpy).sub.2 Ru(vpy).sub.2 ].sup.2+ as an inner film and the aforementioned copolymer of Ru/Re yields even greater reactivity to CO.sub.2.A method of forming a polymeric film on an electrode.A method of reducing CO.sub.2 to CO using an electrode having a polymeric film adsorbed to its surface.