Colloidal copper nanospheres boost propanol electrosynthesis from CO

Achieving a carbon neutral manufacturing of chemicals is imperative to accelerate the transition towards a sustainable future. Propanol electrosynthesis from CO electroreduction represents a promising alternative to the current manufacturing of this chemical. Yet, the catalyst features driving propanol formation are poorly understood, which limits further advancement in the performance. Herein, we report on a comprehensive mapping of the sensitivity of the CO electroreduction to the catalyst structure exploiting well-defined copper nanocrystals (NCs) with tunable shape and size synthesized via colloidal chemistry. In addition to clarify the dependence from the exposed surfaces, we discover that spheres uniquely promote n-propanol selectivity, which we explain mostly with strain effects. Driven by this novel insight, we achieve unprecedent n-propanol production via electrosynthesis with a copper catalyst. We demonstrate that colloidal copper nanospheres with a diameter of 4 nm deliver n-propanol faradaic efficiency of 39.6±1.4% at 119±4.2 mA/cm2 production rate, the latter being ten times the current state of the art for copper catalysts.