Bifunctional single-molecular heterojunction enables completely selective CO2-to-CO conversion integrated with oxidative 3D nano-polymerization

Abstract

Herein, for the first time, an active and stable bifunctional electrocatalyst has been elaborately designed to achieve the integration of CO₂ reduction and anodic non-classical reaction to efficiently yield products of high value at both electrodes, which was constructed by surface anchoring of a novel multi-azido-group-bearing nickel phthalocyanine onto carbon nanotubes at the single-molecule level via strong interactions. Concretely, the obtained heterojunction-type electrocatalyst exhibits ultrahigh activity for completely selective CO₂-to-CO conversion with a 100% faradaic efficiency in a wide potential window, large partial current density (>200 mA cm⁻²) and turnover frequency, and remarkable stability. Particularly, a mass of azido-derived amine groups around the nickel phthalocyanine centers increase the local concentration of CO₂via chemisorption, thus boosting the formation of the key intermediate. Unprecedentedly, an exotic electrolytic system integrating CO₂ reduction with oxidative nano-polymerization was further conceptually developed using this individual bifunctional electrocatalyst for both the cathode and anode. Besides the high-performance CO₂ reduction at the cathode, a unique porous 3D polymer nano-framework was obtained in the anode chamber instead of low-value O₂, while the cell voltage was significantly reduced by 1.05 V to achieve 10 mA cm⁻².