Directional Assembly of Radicals to Methanol in CH₄/H₂O Plasma Mediated by BN-Confined Single Iron Atoms

Directly converting methane into high-value-added chemicals presents a significant challenge in catalysis. Nonthermal plasma (NTP) offers an efficient approach for direct methanol synthesis through methane activation. However, theoretical frameworks for designing catalysts under NTP conditions remain underdeveloped. It is quite difficult to control the assembly process of radical species on catalyst surfaces. A boron nitride (BN)-confined Fe single-atom catalysts (Fe-SACs) is synthesized by in situ anchoring in defect sites induced by mechanical ball milling. This catalyst is utilized for NTP-catalyzed direct methane-to-methanol conversion. The results demonstrate that the CH₃OH yield increases by ≈2.5 times compared to conditions with NTP alone, while selectivity doubles. The experimental results and theoretical calculations indicate that ·OH radicals generated by the dissociation of H₂O are rapidly adsorbed by Fe-SACs before annihilation. This process facilitates the stabilization of ·CH₃ species and enhances the kinetics of CH₃OH assembly along the E-R reaction pathway. A design criterion is proposed for plasma-catalyzed radical adsorption intensification-directed assembly catalysts, offering a novel approach for the directional catalytic conversion of reactants through radical pathways.