S‐Doping Regulated Iron Spin States in Fe−N−C Single‐Atom Material for Enhanced Peroxidase‐Mimicking Activity at Neutral pH

Abstract

Designing biomimetic nanomaterials with peroxidase (POD)‐like activity at neutral pH remains a significant challenge. An S‐doping strategy is developed to afford an iron single‐atom nanomaterial (Fe1@CN‐S) with high POD‐like activity under neutral conditions. To the best of knowledge, there is the first example on the achievement of excellent POD‐like activity under neutral conditions by regulating the active site structure. S‐doping not only promotes the dissociation of the N─H bond in 3,3″,5,5″‐tetramethylbenzidine (TMB), but also facilitates the desorption of OH* by the transformation of iron species’ spin states from middle‐spin (MS FeII) to low‐spin (LS FeII). Meanwhile, LS FeII sites typically have more unfilled d orbitals, thereby exhibiting stronger interactions with H2O2 than MS FeII, which can enhance POD‐like activity. Finally, a one‐pot visual detection of glucose at pH 7 is performed, demonstrating the best selectivity and sensitivity than previous reports.

Iron single-atom anchored N-doped carbon: an efficient catalyst for one-pot, scaled-up pentazolate synthesis

“…Rhombic signals were observed after the reaction of hemin and Fe 1 @NC-700 with excess m CPBA, thereby demonstrating the existence of a Fe( iv )O intermediate. 17 The EPR singlet intensity of Fe 1 @NC-700 is higher than that of hemin, suggesting that Fe 1 @NC-700 is more conducive to the generation of Fe( iv )O than hemin. No singlet was detected in the case of FeCl 2 , which means that it failed to react with m CPBA to afford Fe( iv )O.…”