Dual spillover of carbon monoxide and hydrogen initiates tandem urea electrosynthesis.

Li, Yuefei; Han, Bingying; Liu, Yurong; Liu, Ye; Zhang, Riguang; Wang, Baojun; Chen, Yu; Xia, Bao Yu et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Electrochemical urea synthesis from CO<sub>2</sub> and NO<sub>3</sub><sup>-</sup> provides a sustainable alternative to industrial processes, yet remains challenged by inefficient C-N coupling and protonation. Here, we present a tandem urea electrosynthesis pathway over copper-supported palladium hydride (PdH<sub>x</sub>/Cu) through a dual spillover of CO* and H*. This pathway undergoes efficient CO<sub>2</sub>-to-CO* conversion on PdH<sub>x</sub> and facile NO<sub>3</sub><sup>-</sup>-to-NO* conversion on Cu. Crucially, rapid spillover of CO* (from PdHx surface) and H* (from PdH<sub>x</sub> lattice) to Cu facilitates key C-N intermediate (OCNO*) formation and protonation, respectively. Our catalysts demonstrated high performance, achieving a urea production rate of 236.5 ± 8.9 mmol g<sub>cat</sub><sup>-1</sup> h<sup>-1</sup> with a Faradaic efficiency for urea of 62.6 ± 1.8%. With these catalysts, our scaled-up flow cell enabled continuous co-production of urea and formate with consistent profitability and much lower CO<sub>2</sub> emissions compared to these for the present-day urea production route. This achievement represents a significant step for sustainable urea production.