How to teach an old dog new (electrochemical) tricks: aziridine-functionalized CNTs as efficient electrocatalysts for the selective CO2 reduction to CO

Abstract

The electrocatalytic conversion of CO₂ to energy-rich chemicals or energy vectors is a highly challenging approach to cope with an ever increasing demand for energy storage and valorization of renewable resources. Herein we report on the electrocatalytic reduction of CO₂ to CO using covalently N-decorated carbon nanotubes as highly efficient and chemoselective metal-free electrocatalysts. At odds with more conventional synthetic methods for the production of N-doped nanocarbons, chemical functionalization warrants a unique control of “surface N-defects” available for the process, ruling out any synergistic contribution to electrocatalysis coming from other surface or bulk N-containing groups. With a CO faradaic efficiency (FE_CO) close to 90% and productivity as high as 48 NL^CO g_N⁻¹ h⁻¹, NH-aziridine functionalized MWCNTs have shown CO₂RR performance that is among the highest reported so far for related metal-free systems. At the same time, it has offered a unique view-point for the comprehension of the underlying structure–reactivity relationship.