Second-shell S-coordinated Fe single atoms enable selective generation of heterogeneous Fe(IV)=O for powerful Fenton-like reactions by Bin Han instant download

Second-shell S-coordinated Fe single atoms enable selective generation of heterogeneous Fe(IV)=O for powerful Fenton-like reactions by Bin Han instant download

ABSTRACTKeywords:Heterogeneous high-valent iron-oxo (FeIV=O), a kind of interfacial reactive oxygen species (ROSs) with high High-valent Fe(IV)-oxoselectivity and tunable oxidizability, offers great potential for breaking the trade-off between activity and Advanced oxidation processesselectivity of free ROSs. However, selective generation of heterogeneous FeIV=O with high efficiency remains a Single-atom catalystsgreat challenge, particularly because singlet oxygen (1O2) and FeIV=O are both often categorized as non-radicals Interfacial ROSsand the regulation between them is frequently disregarded. Herein, via coordination engineering of Fe-N-C ROSs regulationsingle-atom catalysts (Fe-NC SACs), we present a facile strategy for the precise regulation between interfacial and free ROSs. Fe-NC SACs with second-shell S functionalization (Fe-NSC SACs) exerts boosted performance for FeIV=O generation with 100 % selectivity, while both FeIV=O and 1O2 can be detected in the Fe-NC SACs/PMS system. Consequently, the Fe-NSC SACs/PMS system can selectively degrade various pollutants within minutes, along with a 2.1- to 4.7-fold increase in degradation rate over its Fe-NC SACs counterpart, outperforming most reported systems under similar conditions. In-situ characterizations and density functional theory (DFT) calculations illustrate that S doping creates electron-rich Fe sites, which benefits the dissociation of FeIV=O-*SO4H and inhibits the in-situ O desorption from FeIV=O sites, thereby synergistically promoting PMS-to-FeIV=O conversion.