Recently, a research group headed by Prof. LU Jiong from National University of Singapore, collaborated with researchers from High Magnetic Field Laboratory (HMFL) Hefei Institutes of Physical Science (HFIPS) of Chinese Academy of Sciences (CAS), developed a scalable hydrothermal approach, which enables the synthesis of various single-atom spin catalysts with widely tunable substitutional magnetic atoms when conducted in an operando acidic environment.
The research results were published in Nature Nanotechnology, offering promising insights into the development of highly efficient catalysts for chemical reactions.
Heterogeneous single-atom spin catalysts, when combined with magnetic fields, offered a powerful means to accelerate chemical reactions with enhanced metal utilization and reaction efficiency. Nevertheless, designing such catalysts has posed significant challenges. They require a high density of atomically dispersed active sites with both short-range quantum spin exchange interaction and long-range ferromagnetic ordering.
In this study, researchers successfully developed various single-atom spin catalysts, with one notable example being the Ni1/MoS2 catalyst. It adopted a distorted tetragonal structure, which prompted ferromagnetic coupling with nearby S atoms as well as adjacent Ni1 sites. This results in global room-temperature ferromagnetism, as confirmed by electron spin resonance (ESR) measurements from HMFL.
Especially, the application of a mild magnetic field of approximately 0.5 Tesla brought a significant increase of approximately 2,880% in the magnetocurrent of the oxygen evolution reaction. This enhancement translated into excellent activity and stability in both seawater and pure water splitting cells. The underlying mechanism involved a reduction in the reaction barrier, attributed to lower adsorption energies for radical intermediates.
These findings shed light on the powerful magnetoelectric effect generated by magnetic fields and ferromagnetic single-atom spin catalysts, effectively accelerating both water and saline water electrolysis processes.
Synthesis and giant magnetic field enhancement of ferromagnetic Ni1/MoS2 single-atom spin catalyst for OER and water splitting. (Image by CAO Liang)