Scalable Electrode\nEngineering Techniques for Achieving\nSelective Ethanol Production Using Commercial Copper Catalysts

In\nthe field of electrochemical CO<sub>2</sub> reduction\n(CO<sub>2</sub>R), electrode engineering plays a crucial role in modulating\nthe distribution of complex products. Here, based on multiphysics\nmodeling, we demonstrate that CO<sub>2</sub>R product selectivity\nvaries spatially along the thickness of the catalyst layer of the\ngas diffusion electrode (GDE). Our calculations indicate that maintaining\na moderately low local CO<sub>2</sub> concentration around catalytic\nsites enables optimal ethanol Faradaic efficiency on Cu. We further\ndeveloped an optimized electrode using commercial Cu nanoparticles\nwith a low catalyst loading of 0.1 mg cm<sup>–2</sup>. Even\nunder a low CO<sub>2</sub> feed concentration of 30%, we achieved\na Faradaic efficiency of approximately 65% for ethanol at an industrial-scale\ncurrent density of–156 mA cm<sup>–2</sup> and over 80%\nfor C<sub>2+</sub> products, along with a promising cathodic energy\nefficiency of more than 37% for ethanol. This study serves as a scalable\nand instructive guide for tuning the local CO<sub>2</sub> concentration\nto achieve optimal production of a single high-selectivity C<sub>2+</sub> product.