Plasma-Assisted Controllable Doping of Nitrogen into MoS2 Nanosheets as Efficient Nanozymes with Enhanced Peroxidase-Like Catalysis Activity

Heteroatom doping is one of the effective ways to improve the catalytic performances of nanozymes. In the present work, the plasma-assisted controllable doping of nitrogen (N) into MoS2 nanosheets has been initially proposed, resulting in efficient nanozymes. The so-obtained nanozymes were characterized separately by TEM, XRD, XPS, and FTIR. It was discovered that the resulting N-doped MoS2 nanosheets could present dramatically enhanced peroxidase-like catalytic activities depending on the plasma treatment time. Particularly, that with the 2-min treatment could display the highest catalytic activity, which is over 3-fold higher than that of pristine MoS2, that was also demonstrated by the kinetics studies. Herein, the N-2 plasma treatment could facilitate the N elements to be doped covalently into MoS2 nanosheets to achieve the increased surface wettability and affinity of nanozymes for the improved access of the electrons and substrates of catalytic reactions. More importantly, the covalent doping of N elements into MoS2 nanosheets with a lower Fermi level, as evidenced by the DFT analysis, could facilitate the promoted electron transferring, resulting in the enhanced catalysis of N-doped MoS2 nanozymes, in addition to the high catalytic stability in water. Such a controllable plasma treatment strategy may open a new door toward the large-scale applications for doping heteroatoms into various nanozymes with improved catalysis performances.