An ideal confined catalytic model via MOFs derived yolk-shell nanoreactors: The formation mechanism and catalytic performance for single-core and multi-core

Yolk-shell nanoreactors with diversified structure has received enormous attention in field of catalytic degra-dation due to the confined catalytic mechanism. Here, the single-core and multi-core yolk-shell nanoreactors are easily prepared by thermolysis of ZIF-67@SiO2 precursor, where the controllable single-core and multi-core structures are adjusted by variable pyrolysis process. In order to confirm the effect of structure on catalytic mechanism and performance, tetracycline hydrochloride (TTCH), a common antibiotic, was selected as the model pollutant for degradation. Under the optimal conditions, the reaction rate of single-core yolk-shell nanoreactors (SCYSN) reached 0.067 min-1, and the degradation efficiency of TTCH reached 85.05% within 25 min. However multi-core yolk-shell nanoreactors (MCYSN) reached 0.079 min-1, and the degradation efficiency of TTCH reached 93.7% at the same time. The radical mechanism was confirmed by quenching experiments and electron paramagnetic resonance. Degradation pathway was inferred by three-dimensional fluorescence spec-trum and liquid chromatography-mass spectrograph. Biotoxicity tests was conducted on the degradation prod-ucts by culturing Staphylococcus aureus. This work demonstrates an ideal confined catalytic model for yolk-shell nanoreactors in field of environmental remediation.