Search

Understanding the activity phases and reaction mechanisms at the atomic level is essential for the design of electrocatalysts. Herein we investigate the origin of the facet-dependent activity of model Cu 2 O catalyst for C-N coupling toward electrocatalytic urea synthesis. It was found that the activity of urea synthesis depends on the crystalline facets of Cu 2 O. The Cu 2 O (100) facet exhibits higher urea activity and selectivity than the (110) facet, with an average urea yield of 62.4 mmol·g−1·h−1 at –1.5 V (RHE). By using Raman, UV–vis and XPS techniques, it was observed that Cu+ serves as active sites at (100) face of Cu 2 O, which promotes C-N coupling through synergistic interaction with Cu0. Furthermore, the combined results of operando ATR-SEIRAS and DFT calculations demonstrate that the Cu-Cu 2 O (100) facet facilitates electrocatalytic C-N coupling between *CO and *NH intermediates due to the reduced energy barriers of hydrogenated *NO on the Cu-Cu 2 O (100) facet. [Display omitted] • The origin of the facet-dependent active sites of Cu 2 O for selective C-N coupling was revealed. • Cu+ is the main active site in the Cu 2 O (100), promoting C-N coupling through synergistic interaction with Cu0. • The Cu-Cu 2 O (100) facet reduced the energy barriers for the hydrogenation *NO, and thus facilitates the electrocatalytic C-N coupling between *CO and *NH intermediates. [ABSTRACT FROM AUTHOR]