Asymmetric spin exchange interaction induced by orderly bimetal atomic-hybridization optimizes nitrate reduction electrocatalysis

Abstract

The electrochemical technology offers a sustainable and promising route to convert nitrate pollutants into valuable ammonia. However, the development of this technique is seriously hampered by the sluggish multi-electron reaction kinetics and complex competing reactions. Here, we report a strategy to induce symmetry-breaking-dependent orbital hybridization to achieve spin-dependent electronic renormalization. The as-prepared Co_0.5Fe_0.5In₂S₄ nanoflowers optimize charge transfer and bond interactions with intermediates via double exchange interactions on half-filled three-dimensional metal active sites. As a result, this particular catalyst enables an impressive NH₃ generation rate of 7.7 mg h⁻¹ cm⁻² and an outstanding Faradaic efficiency of 95.3 % at −0.5 V (RHE), which is significantly superior to the pristine CoIn₂S₄ and FeIn₂S₄. This work provides new insights into spin-related catalytic mechanism from nitrate to ammonia production.