d-Electron Asymmetry-Driven CN Coupling on Heteronuclear Dual-Atom Catalysts for Sustainable Urea Electrosynthesis

Abstract

The transition toward carbon-neutral chemical manufacturing calls for innovative strategies to produce nitrogen-based compounds with minimal environmental impact. Urea, a key nitrogen-rich chemical, is currently synthesized via the energy-intensive Bosch-Meiser process, which relies heavily on fossil fuel-derived ammonia. As a sustainable alternative, electrochemical urea synthesis (ECUS) enables the direct coupling of nitrogenous and carbonaceous precursors under ambient conditions, yet remains hampered by sluggish kinetics and poor selectivity—particularly in the critical C─N bond formation step. Here, density functional theory (DFT) calculations is integrated with data-driven machine learning to systematically explore the activity landscape of nitrogen-doped graphene-supported dual-metal-atom catalysts (M′M@NC) for C─N coupling. A comprehensive reaction network is evaluated across 45 M′M@NC configurations, revealing three heteronuclear catalysts—VNi@NC, CoNi@NC and CoCu@NC—with consistently favorable thermodynamic and kinetic performance. Electronic structure analysis indicates that heteronuclear coordination promotes *CO activation and optimizes *NHx adsorption, facilitating C─N coupling. Leveraging symbolic regression via the sure independence screening and sparsifying operator (SISSO) algorithm, interpretable descriptors linking C─N coupling energy to atomic-level electronic properties is established, highlighting the critical role of d-electron asymmetry. This results uncover fundamental design principles for dual-atom catalysts and provide a predictive framework for guiding the development of next-generation electrocatalysts for sustainable urea synthesis.