A Spin Descriptor Map Predicts NiFe2O4 for Efficient Electrosynthesis of Cyclohexanone Oxime

The selective hydrogenation of NO to NH2OH governs the performance of cyclohexanone oxime electrosynthesis. However, the spin state transition during the NO-to-NH2OH process, which is directly related to reaction pathways, has long been ignored. Here, we propose a spin locking mechanism via density functional theory and sure independence screening and sparsifying operator. Magnetic sites with medium spin states stabilize the *NHO intermediate by locking the spin configuration of NO to weaken *NH2OH adsorption for high selectivity. The spin magnetic moment (µS), the angle between *N-O and the catalyst (θ), and the charge state (q) are key factors, providing a screening range of the predictive metrics (µS·θ)3 and (cos θ/q). The theoretically selected NiFe2O4 delivers 70% Faradaic efficiency for cyclohexanone oxime, and weakened *NH2OH adsorption is revealed by in situ spectroscopy. This work highlights the importance of spin regulation in adjusting the selectivity of electrosynthesis.