Artificial frustrated Lewis pairs facilitating the electrochemical N2 and CO2 conversion to urea

Frustrated Lewis pairs (FLPs) containing sterically hindered Lewis acidic and basic sites can capture and react with N2 and CO2, thus furnishing a new strategy for urea electrosynthesis. Herein, the rice-like InOOH nanoparticles coupled with the well-defined FLPs (i.e., In In-OH) were synthesized and exhibited a urea yield rate of 6.85 mmol h−1 g−1 and faradic efficiency of 20.97% at −0.4 V versus reversible hydrogen electrode. Systematic investigations reveal that the electron-deficient Lewis acidic In sites and electron-rich Lewis basic In-OH achieve the targeted chemisorption of the N2 and CO2 molecules by electronic interaction respectively. The bonding and antibonding orbitals of reactant molecules interact with the unoccupied orbitals of Lewis acid and nonbonding orbitals of Lewis base to generate the desired intermediates for urea synthesis in artificial FLPs. In addition, FLPs can further ensure the orbital-matched intermediates of ∗N=N∗ and CO proceed with the desirable C–N coupling reaction to produce ∗NCON∗ precursors.