Roles of copper(I) in water-promoted CO<sub>2</sub> electrolysis to multi-carbon compounds.

He, Xiaoyang; Lin, Li; Li, Xiangying; Zhu, Minzhi; Zhang, Qinghong; Xie, Shunji; Mei, Bingbao; Sun, Fanfei et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

The membrane electrode assembly (MEA) is promising for practical applications of the electrocatalytic CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) to multi-carbon (C<sub>2+</sub>) compounds. Water management is crucial in the MEA electrolyser without catholyte, but few studies have clarified whether the co-feeding water in cathode can enhance C<sub>2+</sub> formation. Here, we report our discovery of pivotal roles of a suitable nanocomposite electrocatalyst with abundant Cu<sub>2</sub>O-Cu<sup>0</sup> interfaces in accomplishing water-promoting effect on C<sub>2+</sub> formation, achieving a current density of 1.0 A cm<sup>-2</sup> and a 19% single-pass C<sub>2+</sub> yield at 80% C<sub>2+</sub> Faradaic efficiency in MEA. The operando characterizations confirm the co-existence of Cu<sup>+</sup> with Cu<sup>0</sup> during CO<sub>2</sub>RR at ampere-level current densities. Our studies reveal that Cu<sup>+</sup> works for water activation and aids C‒C coupling by enhancing formations of adsorbed CO and CHO species. This work offers a strategy to boost CO<sub>2</sub>RR to C<sub>2+</sub> compounds in industrial-relevant MEA by combining water management and electrocatalyst design.