Interfaces Enhanced <i>n</i> -Propanol Electrosynthesis by Impeding C ₂ Intermediate Desorption in CO Conversion

Electrocatalytic carbon monoxide reduction (ECOR) offers a promising route to n-propanol with higher Faradaic efficiency than CO2 reduction, but often relies on costly precious-metal catalysts. Therefore, developing efficient non-noble metal catalysts is essential. Herein, we report a grain-boundary-rich Cu2O nanoparticle catalyst that achieves a high n-propanol Faradaic efficiency of 32.1% at −0.78 V vs RHE in a flow cell, with 100 h stability. In situ spectroscopy and ab initio molecular dynamics simulation reveal that the grain boundaries stabilize mixed Cu(I)/Cu(0) sites, which preserve a high Cu(I) proportion. This Cu(I)/Cu(0) interface enriches *CO coverage and suppresses *COCOH desorption, while a high proportion of Cu(I) facilitates the coupling of a C2 intermediate with a third *CO molecule to promote n-propanol formation. This work demonstrates a precious-metal-free electrosynthesis process for n-propanol with notable selectivity while also providing key mechanistic insights.