Leaded Bronze Alloy as a Catalyst for the Electroreduction of CO2

The performance of a leaded bronze alloy with CuSn7Pb15 (wt%) chemical composition is studied as a cathode material for CO2 electroreduction (CO2RR) in aqueous 0.5 M KHCO3 electrolyte. It was found that the catalytic characteristics of the proposed CO2RR electrocatalyst are dominated by elemental lead. Surface characterization by means of digital 3D optical microscopy, white light interferometry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and scanning auger microscopy (SAM) revealed that segregated Pb clusters embedded in a Cu-rich Cu/Sn matrix are, to a large extent, dispersed on the cathode surface upon sample preparation through mechanical polishing. Identical location SEM-EDX studies before and after CO2 electrolysis revealed that further Pb surface redistribution takes place under operando CO2RR conditions, provided sufficiently high potentials are applied. The as-prepared electrocatalyst proved to be a suitable and powerful alternative for the selective and efficient production of formate (maximum achieved faradaic efficiency and partial current density for formate are 58.6% and 11.08 mAcm 2 at 1.07 V and 1.17 V vs. RHE, respectively). Moreover, in comparison to neat lead, this material can be handled with less precaution.