High carbon utilization in CO2 reduction to multi-carbon products in acidic media

Renewable electricity-powered CO ₂ reduction to multi-carbon (C ₂₊) products offers a promising route to realization of low-carbon-footprint fuels and chemicals. However, a major fraction of input CO ₂ (>85%) is consumed by the electrolyte through reactions with hydroxide to form carbonate/bicarbonate in both alkaline and neutral reactors. Acidic conditions offer a solution to overcoming this limitation, but also promote the hydrogen evolution reaction. Here we report a design strategy that suppresses hydrogen evolution reaction activity by maximizing the co-adsorption of CO and CO ₂ on Cu-based catalysts to weaken H* binding. Using density functional theory studies, we found Pd–Cu promising for selective C ₂₊ production over C ₁, with the lowest ∆G _OCCOH* and ∆G _OCCOH* - ∆G _CHO*. We synthesized Pd–Cu catalysts and report a crossover-free system (liquid product crossover <0.05%) with a Faradaic efficiency of 89 ± 4% for CO ₂ to C ₂₊ at 500 mA cm ⁻², simultaneous with single-pass CO ₂ utilization of 60 ± 2% to C ₂₊. [Figure not available: see fulltext.]