Selective n-propanol electrosynthesis from CO 2 by promoting C 1 −C 2 coupling between *CO and *OC 2 H 5 intermediates over ultrastable sites at Cu(111)/Cu 2 O(111) phase boundaries

Abstract Electrochemical CO2 reduction (eCO2RR) toward n-propanol (n-PrOH) is a promising strategy for the efficient utilization of renewable electricity and the achievement of carbon neutrality. However, both the catalytic activity and selectivity for n-PrOH production are still unsatisfactory and the underlying mechanism remains to be fully elucidated. Herein, we demonstrate phase boundary-rich copper catalysts (Cu(T)-600-320) for enhanced eCO2RR-to-n-PrOH performance via facilitating the coupling between key intermediates of *CO and *OC2H5. Catalytically active sites at Cu(111)/Cu2O(111) phase boundaries on Cu(T)-600-320 are ultrastable for the eCO2RR under industrial-level current density conditions, even without any external regulators. In the flow cell, the n-PrOH Faradaic efficiency reaches 19.3% with a high partial current density of 77.2 mA·cm−2 at −0.88 V versus reversible hydrogen electrode, outperforming the performance of most reported catalysts. In situ spectroscopy studies, control experiments, and density functional theory calculations unambiguously elucidate that n-PrOH is generated via the *CO + *OC2H5 → *OCHCH2CH3 pathway over Cu(T)-600-320. This work offers new insights into the rational design of high-performance copper-based catalysts targeting C3 products generation via eCO2RR.