Boosting Urea Electrosynthesis via Asymmetric Oxygen Vacancies in Zn‐Doped Fe <sub>2</sub> O <sub>3</sub> Catalysts
Xinning Song, Xiangyuan Jin, Tianhui Chen, Shoujie Liu, Xiaodong Ma, Xingxing Tan, Ruhan Wang, Libing Zhang, Xing Tong, Ziwei Zhao, Xinchen Kang, Qinggong Zhu, Qingli Qian, Xiaofu Sun, Buxing Han
Abstract
Abstract Urea electrosynthesis from CO 2 and nitrate (NO 3 − ) provides an attractive pathway for storing renewable electricity and substituting traditional energy‐intensive urea synthesis technology. However, the kinetics mismatching between CO 2 reduction and NO 3 − reduction, as well as the difficulty of C─N coupling, are major challenges in urea electrosynthesis. Herein, we first calculated the free energy of *CO, *OCNO, and *NOH formation over defect‐rich Fe 2 O 3 catalysts with different metal dopants, which showed that Zn dopant was a promising candidate. Based on the theoretical study, we developed Zn‐doped defect‐rich Fe 2 O 3 catalysts (Zn–Fe 2 O 3 /O V ) containing asymmetric Zn–O V –Fe sites. It exhibited an outstanding urea faradaic efficiency of 62.4% and the remarkable recycling stability. The production rate of urea was as high as 7.48 mg h −1 mg cat −1 , which is higher than most of the reported works to date. Detailed control experiments and in situ spectroscopy analyses identified *OCNO as a crucial intermediate for C─N coupling. The Zn–Fe 2 O 3 /O V catalyst with asymmetric Zn–O V –Fe sites showed enhanced *CO coverage and promoted *OCNO formation, leading to high efficiency toward urea production.