Highly Efficient Electrocatalytic CO₂ Reduction to C₂₊ Products on a Poly(ionic liquid)‐Based Cu⁰–Cu^I Tandem Catalyst

Abstract

Electroreduction of CO₂ on a polymer-modified Cu-based catalyst has shown high multi-electron reduction (>2 e^- ) selectivity, however, most of the corresponding current densities are still too small to support industrial applications. In this work, we designed a poly(ionic liquid) (PIL)-based Cu⁰ -Cu^I tandem catalyst for the production of C₂₊ products with both high reaction rate and high selectivity. Remarkably, a high C₂₊ faradaic efficiency (FE <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow></mml:mrow> <mml:mrow><mml:mi>C</mml:mi> <mml:msub><mml:mrow></mml:mrow> <mml:mrow><mml:mn>2</mml:mn> <mml:mo>+</mml:mo></mml:mrow> </mml:msub> </mml:mrow> </mml:msub> </mml:math> ) of 76.1 % with a high partial current density of 304.2 mA cm^-2 is obtained. Mechanistic studies reveal the numbers and highly dispersed Cu⁰ -PIL-Cu^I interfaces are vital for such reactivity. Specifically, Cu nanoparticles derived Cu⁰ -PIL interfaces account for high current density and a moderate C₂₊ selectivity, whereas Cu^I species derived PIL-Cu^I interfaces exhibit high activity for C-C coupling with the local enriched *CO intermediate. Furthermore, the presence of the PIL layer promotes the C₂₊ selectivity by lowering the barrier of C-C coupling.