Thermal sculpting of nanoconfined single-atom cavities enables urea electrosynthesis with near-unity selectivity

Abstract

Electrocatalytic urea synthesis from CO 2 and NO 3 – offers a sustainable alternative to energy-intensive industrial methods, yet precise C–N coupling remains hindered by kinetic mismatches between the reduction reactions. Here, we report a strategy leveraging programmable Zn-node gasification to thermally sculpt 1.5–1.8 nm cavities within zeolitic imidazolate frameworks, hosting atomically dispersed Cu–N 4 sites. Thermal transformation creates size-matched nanoconfined environments for selective catalysis. An optimal confinement metric descriptor (9.64) is introduced as a predictive parameter, correlating cavity geometry with local electric-field and Cu d-band modulation. This design stabilizes *CO and *NO intermediates, effectively suppressing parasitic reactions and lowering C–N coupling barriers. Consequently, the catalyst delivers a urea yield of 71.32 g g cat –1 h –1 with 98.9% Faradaic efficiency (FE) in gas diffusion cells. Pilot-scale testing demonstrates stable operation over 300 h with an FE of 90%, establishing nanoconfinement as a design principle for competitive-performance urea electrosynthesis.