Dual-site adsorption regulation on a bcc/fcc heterophase PdCuIn metallene for efficient urea electrosynthesis

Abstract

Electrochemical co-reduction of CO₂ and nitrate to produce urea is a sustainable alternative to the Bosch–Meiser process, yet its practical application is impeded by slow C–N coupling kinetics and limited urea selectivity. Here, we design a bcc/fcc hetero-phase PdCuIn metallene (b/f-PdCuIn-ene) catalyst for urea electrosynthesis from CO₂ and nitrate. The resultant b/f-PdCuIn-ene catalyst achieves a urea yield rate of 2096.2 μg h⁻¹ mg_cat.⁻¹ and a faradaic efficiency of 37.7% at a low potential of −0.3 V vs. the reversible hydrogen electrode, along with good stability. Attenuated total reflection Fourier transform infrared spectroscopy verifies the generation of key *CO and *NH₂ intermediates during the CO₂/nitrate co-reduction process. Density functional theory calculations reveal that the bcc/fcc hetero-phase structure could balance the adsorption of *CO and *NH₂ intermediates and promote the C–N coupling reaction for urea synthesis. This study provides an effective crystal phase engineering strategy for tailoring metallene catalysts toward urea electrosynthesis.