Evidence for Spin Polarization and Lattice Oxygen Migration During Cyclohexane Oxidation Over CoO _x /Fe ₂ O ₃

Abstract

ABSTRACT The selective aerobic oxidation of alkanes plays a pivotal role in the sustainable conversion of hydrocarbons. However, designing catalysts that facilitate the selective generation of radicals while avoiding side reactions (such as over‐oxidation) remains a major challenge. Herein, we demonstrate the enhanced spin polarization and lattice oxygen migration on CoO x /Fe 2 O 3 catalyst for cyclohexane oxidation under solvent‐free conditions. We introduce highly dispersed CoO x clusters on iron oxide nanorods (Co/FeNR) through atomic layer deposition, forming interfacial Co–O–Fe active sites. The high‐spin Co atoms modulate the spin‐state of neighboring Fe atoms via double‐exchange interaction, promoting the adsorption and dissociation of triplet molecular oxygen. Meanwhile, Co effectively enhances the mobility of lattice oxygen, further forming the interface‐confined radical intermediate. Both spin polarization‐promoted oxygen activation and lattice oxygen migration drive the transformation of interface‐confined radicals, thus suppressing side reactions and enhancing selectivity. Benefiting from these effects, the 5Co/FeNR achieves 14.6% conversion and 82.7% selectivity for KA oil and mass‐specific reaction rate of 830.7 mmol·g cat −1 ·h −1 , which is approximately 6 times that of FeNR. This study provides valuable insights into the rational design of efficient oxidation catalysts.