Enhancement of CO2RR product formation on Cu-ZnO-based electrodes by varying ink formulation and post treatment methods

Numerous catalysts have been reported with enhanced performance, e.g. longer lifetime and improved selectivity, for the electrochemical CO2 reduction reaction (CO2RR). Respectively little is, however, known about the influence of the electrode structuring and pre-treatment on this reaction for catalytic layers. Thus, we herein report on the modification of the catalyst environment of a Cu-ZnO-carbon black catalyst by variation of the ink composition and subsequent electrode treatment before performing CO2RR. We furthermore provide insight into the impact of solvents used for the ink preparation, ionomer and additives like pore forming agents as well as post treatment steps in terms of pressing and sintering of electrodes on the CO2RR performance. Although using the same catalyst for all electrodes, remarkable differences in hydrophobicity, surface morphology and electrochemical performance with respect to stability and product distribution are observed. Our study reveals the critical role of the catalytic layer assembly aside using proper catalysts. We furthermore show that the parasitic hydrogen formation and flooding behavior can be lowered and C2+ product formation enhanced when operated in optimized gas diffusion electrodes (GDE).