Ni Triple-Atom Doped Cu₂O Electrocatalysts for Efficient Electrochemical Urea Synthesis: A Theoretical Study.

Abstract

Chemical C-N coupling from CO₂ and N₂ toward urea synthesis is an appealing approach for Bosch-Meiser urea production. However, this process faces significant challenges, including the difficulty of N₂ activation, high energy barriers, and low selectivity. In this study, we theoretically designed a Ni triple-atom doped Cu₂O catalyst, Ni TAC@Cu₂O, which exhibits exceptional urea synthesis performance. Using density functional theory and the constant potential method, we show that the superior catalytic performance of Ni TAC@Cu₂O stems from synergistic metal-support interactions (MSIs) between Ni atoms and Cu₂O. Cu₂O serves as an anchoring substrate and actively participates in CO₂ activation via strong Cu-O bonding, whereas Ni serves as the pivotal active center for N₂ activation. Ni TAC@Cu₂O achieves a moderate N₂ adsorption energy and a limiting potential (<i>U</i>_L) of -0.60 V, overperforming Ni single-atom (Ni SAC@Cu₂O, <i>U</i>_L = -0.85 V) and Ni double-atom (Ni DAC@Cu₂O, <i>U</i>_L = -0.88 V) catalysts. The third Ni atom enhances electron donation, reducing the energy barrier of the rate-determining step (*CO + *N₂ + H⁺ + e^- → *CONNH), while O atoms in Cu₂O regulate Ni's electronic structure through MSIs. Additionally, Ni TAC@Cu₂O demonstrates thermodynamic, electrochemical, and acid-base stability and effectively suppresses competing side reactions. This work underscores the importance of Cu₂O-supported MSIs in multiatom catalysts for enhanced performance and provides insights for advanced electrocatalyst design.