Selective urea electrosynthesis via nitrate and CO2 reduction on uncoordinated Zn nanosheets

Abstract

Electroreduction of NO₃⁻ and CO₂ to urea (ENCU) represents a fascinating strategy to enable waste NO₃⁻/CO₂ removal and sustainable urea production. Herein, uncoordinated Zn nanosheets (U-Zn) are developed as a highly selective ENCU catalyst, exhibiting the highest urea-faradaic efficiency of 31.8% with the corresponding urea yield rate of 39.3 mmol h⁻¹ g⁻¹ in a flow cell. Theoretical calculations and electrochemical spectroscopic measurements reveal that the high ENCU performance of U-Zn arises from the critical role of uncoordinated Zn sites that can promote both key steps of *NO₂/CO₂ coupling and *CO₂NH₂ protonation to *COOHNH₂, while retarding the competitive side reactions.