Highly selective electroreduction of N2 and CO2 to urea over artificial frustrated Lewis pairs

The simultaneous electrocatalytic conversion of N-2 and CO2 into value-added urea is highly anticipated but suffers from the predicament of the poor chemisorption, activation, and coupling activity of reactant molecules. Herein, unique frustrated Lewis pairs (FLPs) were precisely designed in flower-like nickel borate [Ni-3(BO3)(2)], where the surface hydroxyl and neighboring Ni site serve as a Lewis base and acid, respectiveLy. Comprehensive investigations endorsed that the Lewis basic and acidic sites in FLPs acted synergistically in the targeted capture of inert CO2 and N-2 by orbital interaction. Subsequently, the bonding and antibonding orbitals of the inert gas interacted with the empty orbitals of the Lewis acid and nonbonding orbitals of the Lewis base, respectively, achieving molecule activation by FLPs. Afterward, the *N=N* and CO intermediates underwent electrocatalytic C-N coupling by the a orbital carbonylation strategy to produce *NCON* precursors. Thus, the prepared Ni-3(BO3)(2)-150 nanocrystal delivered the record-highest urea yield rate of 9.70 mmol h(-1) g(cat)(-1) and a Faradaic efficiency of 20.36% at -0.5 V vs. RHE.

Automated summary

The study achieved efficient conversion of CO2 and N-2 into urea by precisely designing unique frustrated Lewis pairs in flower-like nickel borate crystals. Through the synergistic action of Lewis acidic and basic sites, inert gases were captured and activated, ultimately achieving high urea yield rates.