Charge transfer and vacancy engineering of Fe2O3 nanoparticle catalysts for highly selective N2 reduction towards NH3 synthesis

Fuhao Jin; Hanqing Yin; Ru Feng; Wei Niu; Wanting Zhang; Jingquan Liu; Aijun Du; Wenrong Yang; Zhen Liu

doi:10.1016/j.jcis.2023.05.108

Charge transfer and vacancy engineering of Fe₂O₃ nanoparticle catalysts for highly selective N₂ reduction towards NH₃ synthesis

J Colloid Interface Sci. 2023 Oct:647:354-363. doi: 10.1016/j.jcis.2023.05.108. Epub 2023 May 22.

Authors

Fuhao Jin¹, Hanqing Yin², Ru Feng¹, Wei Niu¹, Wanting Zhang¹, Jingquan Liu¹, Aijun Du², Wenrong Yang³, Zhen Liu⁴

Affiliations

¹ College of Materials Science and Engineering, Institute for Graphene Applied Technology Innovation, Qingdao University, 308 Ningxia Road, Qingdao 266071, PR China.
² School of Chemistry and Physics and Centre for Materials Science, Queensland University of Technology, Gardens Point Campus, Brisbane, 4001, Australia.
³ School of Life and Environmental Sciences, Deakin University, 75 Pigdons Road, Geelong, VIC 3216, Australia.
⁴ College of Materials Science and Engineering, Institute for Graphene Applied Technology Innovation, Qingdao University, 308 Ningxia Road, Qingdao 266071, PR China. Electronic address: zhen.liu@qdu.edu.cn.

PMID: 37267798
DOI: 10.1016/j.jcis.2023.05.108

Abstract

The development of electrocatalysts for N₂ reduction reaction (NRR) is significant for scalable and renewable NH₃ synthesis, but calls for a technology innovation to overcome the specific problems of low efficiency and poor selectivity. Herein, we prepare a core-shell nanostructure by coating polypyrrole (PPy) onto sulfur-doped iron oxide nanoparticles (denoted as S-Fe₂O₃@PPy) as the highly selective and durable electrocatalysts for NRR under ambient conditions. Sulfur doping and PPy coating remarkably improve the charge transfer efficiency of S-Fe₂O₃@PPy, and the interactions between PPy and Fe₂O₃ nanoparticles produce abundant oxygen vacancies as active sites for NRR. This catalyst achieves an NH₃ production rate of 22.1 μg h^-1 mg_cat^-1 and a very-high Faradic efficiency of 24.6%, surpassing other Fe₂O₃ based NRR catalysts. Density functional theory calculations show that the S-coordinated iron site can successfully activate the N₂ molecule and optimize the energy barrier during the reduction process, resulting in a small theoretical limiting potential.

Keywords: Electrocatalysis; Iron oxide nanoparticles; Nitrogen reduction reaction; Oxygen vacancy; Polypyrrole coating; Sulfur doping.