Optimizing the Ink Formulation for Preparation of Cu-Based Gas Diffusion Electrodes Yielding Ethylene in Electroreduction of CO₂

Cu-based gas diffusion electrodes (GDE) show excellent performance in the electrochemical reduction of CO2 to ethylene. In present work, we evaluate how solvent ink formulations containing Nafion-ionomer and unsupported Cu particles affects polymerized Nafion-copper distribution as-prepared GDE obtained CO2. Isopropanol (IPA), dimethyl sulfoxide (DMSO), ethylene glycol (EG), or N-methyl-2-pyrrolidone (NMP)) were used. Microscopic analyses Cu-GDEs demonstrate that NMP DMSO lead exposed islands copper, with Nafion acting predominantly as an interparticle binder. Such geometry is confirmed by relatively high surface area (ECSA) low charge-transfer resistance (Rct). IPA EG induce formation Cu-catalyst embedded into covered (polymerized) films, agreement ECSA, Rct, likely due significant polymerization agglomeration formulation induced protic solvents prior preparation catalyst layer. When evaluated at ?1.1 V vs reversible hydrogen electrode (RHE), prepared using higher FE toward than IPA-based GDEs (23.5% 19.2% 10.2% 13.4%, respectively). The lower for systems tentatively attributed acidity highly effective transport protons Nafion.