CO<sub>2</sub> electrolysis to multicarbon products at activities greater than 1 A cm<sup>-2</sup>.

García de Arquer, F Pelayo; Dinh, Cao-Thang; Ozden, Adnan; Wicks, Joshua; McCallum, Christopher; Kirmani, Ahmad R; Nam, Dae-Hyun; Gabardo, Christine et al. · Science · 2020

basic_science · Level V

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Abstract

Electrolysis offers an attractive route to upgrade greenhouse gases such as carbon dioxide (CO<sub>2</sub>) to valuable fuels and feedstocks; however, productivity is often limited by gas diffusion through a liquid electrolyte to the surface of the catalyst. Here, we present a catalyst:ionomer bulk heterojunction (CIBH) architecture that decouples gas, ion, and electron transport. The CIBH comprises a metal and a superfine ionomer layer with hydrophobic and hydrophilic functionalities that extend gas and ion transport from tens of nanometers to the micrometer scale. By applying this design strategy, we achieved CO<sub>2</sub> electroreduction on copper in 7 M potassium hydroxide electrolyte (pH ≈ 15) with an ethylene partial current density of 1.3 amperes per square centimeter at 45% cathodic energy efficiency.