Direct electrosynthesis of 52% concentrated CO on silver's twin boundary.

Tang, Can; Gong, Peng; Xiao, Taishi; Sun, Zhengzong · Nat Commun · 2021

basic_science · Level V

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Abstract

The gaseous product concentration in direct electrochemical CO<sub>2</sub> reduction is usually hurdled by the electrode's Faradaic efficiency, current density, and inevitable mixing with the unreacted CO<sub>2</sub>. A concentrated gaseous product with high purity will greatly lower the barrier for large-scale CO<sub>2</sub> fixation and follow-up industrial usage. Here, we developed a pneumatic trough setup to collect the CO<sub>2</sub> reduction product from a precisely engineered nanotwinned electrocatalyst, without using ion-exchange membrane. The silver catalyst's twin boundary density can be tuned from 0.3 to 1.5 × 10<sup>4</sup> cm<sup>-1</sup>. With the lengthy and winding twin boundaries, this catalyst exhibits a Faradaic efficiency up to 92% at -1.0 V and a turnover frequency of 127 s<sup>-1</sup> in converting CO<sub>2</sub> to CO. Through a tandem electrochemical-CVD system, we successfully produced CO with a volume percentage of up to 52%, and further transformed it into single layer graphene film.