Regioselective Electrocatalytic Urea Synthesis via Spin‐Polarized PdCu/TiO 2‐x With Oxygen Vacancy Engineering

ABSTRACT Replacing the energy‐intensive Haber–Bosch process with electrocatalytic urea synthesis from waste NO 3 − and CO 2 is hindered by kinetic competition from undesirable *NOH‐mediated NH 3 formation. Herein, we design a spin‐polarized PdCu/TiO 2‐x catalyst with oxygen vacancies (OV) to enable regioselective C‐N coupling. The OV engineering synergistically modulates NO adsorption configurations and suppresses oxygen‐terminal hydrogenation (NO → *NOH), redirecting the pathway toward *NO → *HNO for urea formation. This dynamic control achieves a record urea yield of 37.84 mmol h −1 g −1 at low voltage, outperforming most reported catalysts. Operando attenuated total reflection–surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS) and density functional theory (DFT) studies confirm that OV enhance NO 3 − /CO 2 co‐adsorption, accelerate the rate‐determining NO → HNO step, and stabilize dispersed PdCu clusters for increased active sites. This spin‐defect synergy offers a sustainable strategy for electro‐synthesizing urea while valorizing environmental pollutants.