Oxygen vacancy modulation in interfacial engineering Fe3O4 over carbon nanofiber boosting ambient electrocatalytic N2 reduction

Yang Liu; Edison Huixiang Ang; Xiu Zhong; Hao Lu; Jun Yang; Fei Gao; Chao Yu; Jiawei Zhu; Chengzhang Zhu; Yu Zhou; Fu Yang; Enxian Yuan; Aihua Yuan

doi:10.1016/j.jcis.2023.08.106

Oxygen vacancy modulation in interfacial engineering Fe₃O₄ over carbon nanofiber boosting ambient electrocatalytic N₂ reduction

J Colloid Interface Sci. 2023 Dec 15;652(Pt A):418-428. doi: 10.1016/j.jcis.2023.08.106. Epub 2023 Aug 18.

Authors

Yang Liu¹, Edison Huixiang Ang², Xiu Zhong¹, Hao Lu¹, Jun Yang³, Fei Gao¹, Chao Yu¹, Jiawei Zhu⁴, Chengzhang Zhu⁵, Yu Zhou⁶, Fu Yang⁷, Enxian Yuan⁸, Aihua Yuan¹

Affiliations

¹ School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, China.
² Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore.
³ School of Material Science & Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003, China.
⁴ Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.
⁵ School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, China.
⁶ State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
⁷ School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, China. Electronic address: fuyang@just.edu.cn.
⁸ School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China. Electronic address: exyuan@yzu.edu.cn.

PMID: 37604053
DOI: 10.1016/j.jcis.2023.08.106

Abstract

The oxygen vacancy modulation of interface-engineered Fe₃O₄ nanograins over carbon nanofiber (Fe@CNF) was achieved to improve electrocatalytic nitrogen reduction reaction (NRR) activity and stability via facile electrospinning and tuning thermal procedure. The optimal catalyst calcined at 800 ℃ (Fe@CNF-800) was endowed with abundant nanograin boundaries and optimized oxygen vacancy (V_o) concentration of iron oxides, thereby affording 37.1 μg h^-1 mg_cat.^-1 (-0.2 V vs. reversible hydrogen electrode (RHE)) NH₃ yield and rational Faraday efficiency (10.2%), with 13.6 times atomic activity enhancement compared to of that commercial Fe₃O₄. The interfacial effect of assembled nanograins in particles correlated with the formation of V_o and more intrinsic active sites, which is conducive to the trapping and activation of nitrogen (N₂). The in-situ X-ray photoelectron spectroscopy (XPS) measurement revealed the real consumption of adsorbed oxygen when introducing N₂ by the trapping effect of V_o. Density-Functional-Theory (DFT) calculation validates the promotive hydrogenation effect and elimination of hydrogen intermediate (H*) interacted with N₂ transferring toward oxygen of the support. The optimal catalyst shows a lasting NRR activity at least 90 h, outperforming most reported Fe-based NRR catalysts.

Keywords: Carbon nanofiber; Electrocatalytic nitrogen reduction; Electrospining synthesis; Interfacial engineering; Oxygen vacancies.