Electrochemical Reduction of CO2 with an Oxide-Derived Lead Nano-Coralline Electrode in Dimcarb

Electroreduction of CO2 in the distillable ionic liquid dimethylammonium dimethylcarbamate (dimcarb) has been investigated with an oxide-derived lead (od-Pb) electrode. Compared with unmodified polycrystalline Pb, where H-2 is the dominant electrolysis product, od-Pb possesses impressive catalytic properties for the reduction of CO2 in dimcarb (mixing molar ratio of CO2 and dimethylamine (DMA) > 1: 1.8), with faradaic efficiencies for the generation of H-2, CO, and [HCOO](-) of approximately 15, 10, and 75%, respectively. These efficiencies are independent of the applied potential in the range of -1.34 to -3.34 V vs. Cc(0/+) (where Cc(+) = cobaltocenium). Thorough analysis of the properties of od-Pb, we demonstrate that its intrinsically high catalytic activity towards CO2 reduction compared to bulk Pb is attributable to an increased surface roughness and greater surface area (ca. 10 times higher), rather than the existence of residual metal oxides that are known to suppress the hydrogen evolution reaction, preferred crystal orientation, or the existence of metastable active sites.