Remodeling Interfacial Hydrogen-Bond Network Via Crystal Facet Control for Efficient Urea Electrosynthesis.

Zeng, Qingming; Zhang, Yan; Yu, Shuyan; Wang, Yian; Quan, Xie; Nanayakkara, Nadeeshani; Liu, Yanbiao · Nano Lett · 2026

basic_science · Level V

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Abstract

The electrochemical coreduction of CO2 and nitrate for urea synthesis is hindered by competing side reactions due to conflicting proton demands. Here, using facet-engineered Cu2O nanocrystals, we find that the (100) facet achieves a urea yield of 84.4 mmol h-1 gcat-1, 3.2- and 3.7-fold those of the (111) and (110) facets, and a Faradaic efficiency of 32%, which outperforms the 11% and 8% on the other two facets. By integrating in situ Raman spectroscopy with ab initio molecular dynamics simulations, we elucidate that the (100) facet preferentially accumulates hydrated K+ cations to reorient interfacial water into a constrained "one-H-down" conformation. This restructuring limits proton availability to suppress parasitic H2 and NH3 formation, while the K+-rich field stabilizes *CO and *NO intermediates via electrostatic effects. The combined action of proton restriction and intermediate stabilization lowers the kinetic barrier for C-N coupling and selectively promotes urea formation.