A facile strategy for the preparation of ZnS nanoparticles deposited on montmorillonite and their higher catalytic activity for rapidly colorimetric detection of H₂O₂

Highlights

• ZnS nanocomposites deposited on MMT was synthesized by a facile one step method.

• MMT-ZnS nanocomposites possess excellent intrinsic peroxidase-like activity and show highly catalytic activity.

• A sensitive colorimetric sensor for H₂O₂ is provided based on MMT-ZnS nanocomposites.

• The catalytic mechanism is from the generation of hydroxyl radical (OH) decomposed from H₂O₂.

Abstract

In this paper, ZnS nanoparticles deposited on montmorillonite (ZnS-MMT) were prepared by a facile method at room temperature and characterized by powder X-ray diffraction (XRD), Energy-dispersive X-ray Detector (EDX) and transmission electron microscope (TEM), respectively. Significantly, the as-prepared ZnS-MMT nanocomposites have been proven to possess intrinsic peroxidase-like activity that can rapidly catalyze the reaction of peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H₂O₂ and produce a blue color product in less than 30 seconds, which provides a sensitive colorimetric sensor to detect H₂O₂. Due to the synergistic effects between montmorillonite and ZnS nanoparticles, the obtained ZnS-MMT nanocomposites exhibit higher catalytic activity than that of MMT or ZnS alone. The catalytic behaviors of the ZnS-MMT nanocomposites showed a typical Michaelis–Menten kinetics. The catalytic activity and the catalytic mechanism were investigated using the procedures of steady-state kinetics and hydroxyl radical detection. ESR data revealed that the peroxidase-like activity of ZnS-MMT originated from the generation of OH radicals.