Actinide-uranium single-atom catalysis for electrochemical nitrogen fixation

Tao Chen; Tong Liu; Beibei Pang; Tao Ding; Wei Zhang; Xinyi Shen; Dan Wu; Lan Wang; Xiaokang Liu; Qiquan Luo; Wenkun Zhu; Tao Yao

doi:10.1016/j.scib.2022.09.001

Actinide-uranium single-atom catalysis for electrochemical nitrogen fixation

Sci Bull (Beijing). 2022 Oct 15;67(19):2001-2012. doi: 10.1016/j.scib.2022.09.001. Epub 2022 Sep 3.

Authors

Tao Chen¹, Tong Liu², Beibei Pang², Tao Ding², Wei Zhang², Xinyi Shen², Dan Wu², Lan Wang², Xiaokang Liu², Qiquan Luo³, Wenkun Zhu⁴, Tao Yao⁵

Affiliations

¹ National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China; State Key Laboratory of Environment-friendly Energy Materials, School of National Defense Science and Technology, Southwest University of Science and Technology, Mianyang 621010, China.
² National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China.
³ Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China.
⁴ State Key Laboratory of Environment-friendly Energy Materials, School of National Defense Science and Technology, Southwest University of Science and Technology, Mianyang 621010, China. Electronic address: zhuwenkun@swust.edu.cn.
⁵ National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China. Electronic address: yaot@ustc.edu.cn.

PMID: 36546210
DOI: 10.1016/j.scib.2022.09.001

Abstract

Actinide-based catalysts have been regarded as promising candidates for N₂ fixation owing to their unique 5f orbital with flexible oxidation states. Herein, we report for the first time the dispersion of uranium (U) single atoms on TiO₂ nanosheets via oxygen vacancy confinement for N₂ electroreduction. The single-atom U catalyst exhibited a high NH₃ yield of 40.57 μg h^-1 mg^-1, with a reasonably high Faraday efficiency of 25.77%, ranking first among the reported nitrogen-free catalysts. Isotope-labeling operando synchrotron infrared spectroscopy verifies that the key *N₂H_y intermediate species was derived from the N₂ gas of the feed. By using operando X-ray absorption spectroscopy, we found enhanced metal-support interaction between U single atoms and TiO₂ lattice with more U-O_latt coordination under working conditions. Theoretical simulations suggest that the evolved 1O_ads-U-4O_latt moieties act as a critical electron-feedback center, lowering the thermodynamic energy barrier for the N₂ dissociation and the first hydrogenation step. This work provides the possibility of tailoring the interaction between metal active sites and supports for designing high-performance actinide-based single-atom catalysts.

Keywords: Metal-support interaction; N(2) electroreduction; Operando FTIR; Operando XAFS; Uranium single atoms.