Coupling continuous CO2 electroreduction to formate with efficient Ni-based anodes

Abstract

CO2 electroreduction to formic acid and formate has been focus of great research attention in the last years. Thus, considerable and relevant efforts have been accomplished in this field, mainly by operating with different types of catalysts and electrode configurations in the cathodic compartment. Still, Pt-based anodes, which are expensive and scarce, are typically the preferred materials to carry out the oxygen evolution reaction in alkaline medium. However, it is crucial to search for new materials of lower prices, with high stability, and good performances able to be competitive with traditional Pt-based electrodes. Hence, we study hand-made NiO-based anodes for the continuous CO2 electroreduction for formate in a filter press reactor with a single pass of the reactants through the electrochemical reactor. The use of the NiO-based anodes enhances the results obtained in previous studies with DSA/O2 anodes, combining excellent values of Faradaic Efficiency for formate of 100 %, and energy consumptions values close to only 200 kWh·kmol-1. In addition, employing Sustainion® as a binder in the fabrication of the anode results in a significant improvement in the durability, maintaining similar performance in terms of key metrics.