Non-linear spin correlation of intermediates in enhanced electrochemical nitrate reduction under magnetic fields†
Abstract
Spin in electrocatalysis introduces a pivotal degree of freedom for overcoming thermodynamic and kinetic limitations. Paradigm studies on spin-related enhancement in oxygen electrocatalysis have highlighted the potential role of spin in influencing reaction kinetics. However, establishing spin correlations in reactions involving complex catalytic conversions, such as NH3 synthesis, remains a significant challenge. Herein, we reveal spin correlations in electrochemical nitrate reduction (NO3−RR) by demonstrating enhanced activity under external magnetic fields. The yield rate enhancement under magnetic fields is demonstrated on magnetic CuFe2O4 at 93.2% for NH3 production and more than one order of magnitude for NO2− production. Linear and non-linear correlations between the activity enhancement and spin polarization improvement of CuFe2O4 are revealed for NO3−RR toward NO2− and NH3, respectively. Insights into spin polarization are provided on intermediates with different net spins, which facilitates the development of magnetic electrocatalysts for NO3−RR.