FexSey@C superlattice nanocrystals for peroxymonosulfate activation: Intrinsic nature of Fe spin state

Abstract

Two-dimensional layered carbon-coated FexSey nanocrystal superlattices with different crystalline structure (2D FexSey@C NS) are prepared and tested in Fenton-like reaction via PMS activation. The intrinsic nature and properties that govern the activity of 2D FexSey@C NS are deeply elucidated. Experimental analysis and theoretical calculations indicated that the spin state of Fe strongly decided the catalytic activity of 2D FexSey@C NS, and that a high spin state of Fe (4.16 μB) with a large effective magnetic moment not only regulated PMS adsorption (−3.06 eV) for increasing electronic density (0.79 e), but also accelerated interfacial charge transfer for HSO5− decomposition to produce SO4•−. Therefore, among 2D FexSey@C NS, 2D FeSe2 @C NS exhibited the most active performance in PMS activation with brilliant durability and adaptability. The study illustrates a new application of superlattice nanomaterials in environmental remediation and supplies fundamental insight to the intrinsic chemical structure of Fe-based catalysts for PMS activation.