The optimized Fenton-like activity of Fe single-atom sites by Fe atomic clusters–mediated electronic configuration modulation

Significance

The single-atom catalysts (SACs) have been investigated and recognized as promising alternatives for initializing peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs). Of note, the reasonable property modulation may further drive its practical application. This work suggests that tuning the electronic structure of single-atom sites is of great importance to achieve superior PMS activation kinetics. The Fe-based single-atom catalyst with Fe atomic cluster (ACs) modulation exhibits superior performance than the pure atomically dispersed Fe catalysts. In addition, the visible light can contribute to the formation of electron-deficient Fe species, therefore further improving the reaction activity. This work provides insights into the electronic structure regulation of metal centers at the atomic level.

Abstract

The performance optimization of isolated atomically dispersed metal active sites is critical but challenging. Here, TiO ₂@Fe species-N-C catalysts with Fe atomic clusters (ACs) and satellite Fe-N ₄ active sites were fabricated to initiate peroxymonosulfate (PMS) oxidation reaction. The AC-induced charge redistribution of single atoms (SAs) was verified, thus strengthening the interaction between SAs and PMS. In detail, the incorporation of ACs optimized the HSO ₅ ^- oxidation and SO ₅ ^·− desorption steps, accelerating the reaction progress. As a result, the Vis/TiFeAS/PMS system rapidly eliminated 90.81% of 45 mg/L tetracycline (TC) in 10 min. The reaction process characterization suggested that PMS as an electron donor would transfer electron to Fe species in TiFeAS, generating ¹O ₂. Subsequently, the h _VB ⁺ can induce the generation of electron-deficient Fe species, promoting the reaction circulation. This work provides a strategy to construct catalysts with multiple atom assembly–enabled composite active sites for high-efficiency PMS-based advanced oxidation processes (AOPs).