Scalable Electrode Engineering Techniques for Achieving Selective Ethanol Production Using Commercial Copper Catalysts

In the field of electrochemical CO₂ reduction (CO₂R), electrode engineering plays a crucial role in modulating the distribution of complex products. Here, based on multiphysics modeling, we demonstrate that CO₂R product selectivity varies spatially along the thickness of the catalyst layer of the gas diffusion electrode (GDE). Our calculations indicate that maintaining a moderately low local CO₂ concentration around catalytic sites enables optimal ethanol Faradaic efficiency on Cu. We further developed an optimized electrode using commercial Cu nanoparticles with a low catalyst loading of 0.1 mg cm^–2. Even under a low CO₂ feed concentration of 30%, we achieved a Faradaic efficiency of approximately 65% for ethanol at an industrial-scale current density of–156 mA cm^–2 and over 80% for C₂₊ products, along with a promising cathodic energy efficiency of more than 37% for ethanol. This study serves as a scalable and instructive guide for tuning the local CO₂ concentration to achieve optimal production of a single high-selectivity C₂₊ product.