Spin engineering of single-site metal catalysts

Zichuang Li; Ruguang Ma; Qiangjian Ju; Qian Liu; Lijia Liu; Yufang Zhu; Minghui Yang; Jiacheng Wang

doi:10.1016/j.xinn.2022.100268

Spin engineering of single-site metal catalysts

Innovation (Camb). 2022 Jun 9;3(4):100268. doi: 10.1016/j.xinn.2022.100268. eCollection 2022 Jul 12.

Authors

Zichuang Li^{1

2}, Ruguang Ma^{1

3}, Qiangjian Ju^{1

2}, Qian Liu^{1

2}, Lijia Liu⁴, Yufang Zhu^{1

2}, Minghui Yang⁵, Jiacheng Wang^{1

2

6}

Affiliations

¹ State Key Laboratory of High-Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, China.
² Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
³ School of Materials Science and Engineering, Suzhou University of Science and Technology, 99 Xuefu Road, Suzhou 215009, China.
⁴ Department of Chemistry, Western University, 1151 Richmond Street, London, ON N6A 5B7, Canada.
⁵ Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 1219 Zhongguan West Road, Ningbo 315201, China.
⁶ Hebei Provincial Key Laboratory of Inorganic Nonmetallic Materials, College of Materials Science and Engineering, North China University of Science and Technology, Tangshan 063210, China.

Abstract

Single-site metal atoms (SMAs) on supports are attracting extensive interest as new catalytic systems because of maximized atom utilization and superior performance. However, rational design of configuration-optimized SMAs with high activity from the perspectives of fundamental electron spin is highly challenging. Herein, N-coordinated Fe single atoms are successfully distributed over axial carbon micropores to form dangling-FeN₄ centers (d-FeN₄). This unique d-FeN₄ demonstrates much higher intrinsic activity toward oxygen reduction reaction (ORR) in HClO₄ than FeN₄ without micropore underneath and commercial Pt/C. Both theoretical calculation and electronic structure characterization imply that d-FeN₄ endows central Fe with medium spin (t_2g ⁴ e_g ¹), which provides a spin channel for electron transition compared with FeN₄ with low spin. This leads to the facile formation of the singlet state of oxygen-containing species from triplet oxygen during the ORR, thus showing faster kinetics than FeN₄. This work provides an in-depth understanding of spin tuning on SMAs for advanced energy catalysis.

Keywords: DFT calculation; Single-site metal atoms; oxygen reduction reaction; spin tuning.