The structure-dependent performance and peroxymonosulfate activation mechanism of vacancy-rich Co3S4 hollow nanocages for water purification

Heterogeneous peroxymonosulfate (PMS)-based catalysts have been widely used for pollutant removal from wastewater. However, their limited electron transfer and reactive oxygen species (ROS) utilization efficiency hinder their overall effectiveness. Herein, the sulfurization technique was employed to precisely control the thickness of vacancy -rich Co3S4 hollow nanocages derived from zeolitic imidazolate frameworks (ZIFs). As expected, the optimized H-Co3S4-4.0 exhibited an exceptional degradation rate of tetracycline (0.284 min -1, TC) and a remarkably high PMS utilization efficiency (91.5 %). The experimental results indicated that the degradation of contaminants was primarily driven by the generation of singlet oxygen (1O2). Furthermore, the synergistic effects of reduced sulfur species and hollow structure not only accelerated the Co3+/Co2+ redox cycle but also facilitated the enrichment of reactants, thereby enhancing the long-term catalytic activity. Notably, the HCo3S4-4.0-based flow -through unit exhibited no decline in the removal of TC during continuous operation for 12 h and significantly reduced its biological toxicity. Overall, the combination of nanoconfinement and hollow strategies will prove to be an effective method for fabricating practical catalysts for remediating water pollution.