Spatial confined synthesis of submicron Fe-MoS2 with abundant surface cationic groups and sulfur vacancies for enhanced peroxymonosulfate activation.

Abstract

The widespread use of emerging refractory organic contaminants poses a significant threat to human health, prompting the need for a cost-effective and efficient removal strategy. While the iron ions/PMS system effectively removes organic pollutants, slow Fe³⁺ to Fe²⁺ transformation hampers its efficiency, and the homogeneous distribution of iron ions complicates separation, resulting in secondary sludge pollution. Herein, we developed a novel submicron Fe-MoS₂ (S-Fe-MoS₂) catalyst with abundant surface cationic groups and sulfur vacancy through a cationic polyacrylamide aerogels (CPAMA) confined hydrothermal synthesis strategy. These features promote active site exposure, enhance reactant adsorption, and accelerate electron transfer between Mo and Fe sites, improving catalytic kinetics and promoting Fe³⁺/Fe²⁺ cycle for PMS activation. As a result, the S-Fe-MoS₂/PMS system exhibited a high catalytic rate constant (k_obs) of 0.32 min^-1, in the degradation of 4-chlorophenol (4-CP), 1.5 times higher than that of the conventional Fe-MoS₂/PMS system. It also achieved 82.9% total organic carbon (TOC) degradation within 60 min. Additionally, it possessed similar degradation performance for various organic pollutants, along with remarkable reusability (four cycles) and broad pH adaptability (2-8), indicating significant potential for widespread application. This study provided a new way for developing advanced heterogeneous catalysts with high efficiency for water treatment.