Theory-Guide Design of Integrative Catalytic Pairs for Urea Synthesis from Nitrate and Carbon Dioxide.

Abstract

Electrochemical coreduction of carbon dioxide and nitrate offers a sustainable pathway to synthesize value-added urea from greenhouse gas and nitrogen-containing waste; however, challenges remain in designing efficient catalysts. Based on the concept of "integrative catalytic pairs (ICPs)", a catalyst for urea synthesis is designed by introducing heteroatoms (B and C) into M-N-C, where a single transition metal is dispersed on N-doped carbon material. Using a two-step theoretical screening strategy, Ni-N₃B is identified as a promising catalyst for urea synthesis, with a low limiting potential (-0.43 V) and a small kinetic barrier for C-N coupling (0.74 eV) due to the electronic regulation effects and the synergy of Ni and B function for enhancing NO₃^- activation and facilitating C-N coupling between gaseous CO₂ and *NH intermediate. Under the guidance of these theoretical results, our further experimental validation demonstrates that the synthesized Ni-N₃B catalyst achieves a Faradaic efficiency of 51.92% and a urea yield rate of 32.30 mmol h^-1 g^-1 at -0.6 V vs RHE. Our work not only identifies an efficient urea synthesis catalyst without relying on trial-and-error methods but also inspires further exploration of ICPs-based catalysts in electrocatalysis.