Contact-Electro-Catalysis Enables Ambient Coupling of CO2 and NH3 for Urea

Abstract Urea is an essential chemical for agriculture and industry, yet its production remains dominated by energy-intensive thermochemical processes. Here we report a contact-electro-catalysis (CEC) strategy that enables direct urea synthesis from carbon dioxide and aqueous ammonia under ambient conditions. Mechanical contact electrification (CE) continuously generates interfacial charges at dielectric-liquid interfaces, creating a unique reaction microenvironment characterized by a giant interfacial electric field and local pH gradients. This electric-field-engineered microenvironment promotes the formation and stabilization of neutral carbamic acid (NH2COOH), enabling urea synthesis through a pathway distinct from conventional carbamate-mediated mechanisms. Spectroscopic and isotopic-labeling studies further reveal a persistent cyanate intermediate that converts to urea after ultrasonication, supporting a dual-pathway mechanism centered on NH2COOH. Confocal Raman spectroscopy combined with vibrational Stark effect probes directly quantifies an interfacial electric field of up to 1.5 × 1010 V m–1, orders of magnitude higher than those reported at gas–liquid or liquid–liquid interfaces. Importantly, density functional theory calculations further corroborate that the interfacial field modulates reaction free energies and stabilizes key intermediates. These findings establish CEC as an ambient synthetic paradigm in which the interfacial electric field acts as an active driving force for selective C–N coupling and inorganic-to-organic conversion.