Nitrogen plasma-mediated deposition of silver onto MoS2 towards robust nanozyme with enhanced catalysis for colorimetric assay of hydrogen sulfide in aquaculture water

Abstract

Ultra-thin MoS2 nanosheets were treated by nitrogen (N2) plasma to mediate the photo-reduction deposition of silver forming N/Ag@MoS2 nanozymes for the catalysis-based colorimetric assay of hydrogen sulfide (H2S) in aquaculture water. It was found that the as-produced N/Ag@MoS2 could display a greatly enhanced peroxidase-like catalytic activity than that of MoS2 nanosheets (about three times higher). Also, in the presence of H2S, a strong Ag-S interaction could occur to form non-conductive Ag2S onto N/Ag@MoS2 nanocomposites towards the rationally reduced catalysis depending on H2S concentrations. Herein, on the one hand, the plasma treatment-aided doping of N elements into MoS2 nanosheets might facilitate the robust deposition of silver onto MoS2 nanosheets through the strong Ag-N chelation, and the enhanced internal electron transferring of N/Ag@MoS2 nanozymes. On the other hand, the so deposited silver could not only enhance the catalytic properties of nanozymes, but also act as a specific probe for recognizing H2S to trigger the decreased catalysis of nanozymes. Importantly, such a N2 plasma treatment pathway that mediates the deposition of silver onto two-dimensional structures like MoS2 nanosheets may pave the way toward the design of various nanozymes for the analysis of different targets in the biomedical, food, and environmental monitoring fields.