Application of Co3O4 as anode catalyst in CO2 electrolyzer cells

Abstract Replacing Ir with anode catalyst materials that are more abundant is a long-sought objective within the CO 2 electrolysis community. The chemical environment (near-neutral pH, carbonate buffer electrolyte) that inherently develops during long-term operation, however, limits the pool of applicable candidates. In this contribution, Ir was replaced with a porous Co 3 O 4 nanosheet catalyst layer as the anode of a zero-gap CO 2 electrolyzer cell. The catalyst was directly deposited on the Ti porous transport layer via hydrothermal synthesis, which allowed the precise control of the catalyst loading. Under optimal conditions (7 mg cm -2 Co 3 O 4 loading), 300 mA cm -2 current density was reached at 3.4 V applied cell voltage. The electrolyzer cell with the Co 3 O 4 anode was operated continuously for 50 hours at 250 mA cm -2 current density with stable cell voltage and CO 2 reduction selectivity.