Growth and stabilization of high-concentration metallic 1T-phase MoS2 as a high-performance l-cysteine electrochemical sensor by electron injection engineering

[Display omitted] •CNTs-IL-MoS2 nanomaterials were prepared by hydrothermal in-situ growth method.•Electron injection engineering increases the ratio and stability of metal 1T phase MoS2.•Catalytic oxidation of thiol groups through sulfur defects on the surface of MoS2.•Construct a new screen-printed electrode for the detection of l-cys. MoS2 is an attractive electrochemical sensing electrode material for the detection of biomolecule because of its adjustable band gap, large surface area, and unique electrochemical characteristics. However, the poor catalytic and electrical conductivity of the semiconductor 2H-phase MoS2 and the phenomenon of restacking during electrochemical use hinder its sensing application. Herein, electron injection engineering is employed for the formation and stabilization of high-concentration metal 1T-phase MoS2 nanosheets on ionic liquid-functionalized carbon nanotubes (CNTs-IL). The increase of MoS2 concentration in the metal 1T phase significantly accelerates electron transfer kinetics. The in-situ growth method results in a tightly interfaced coupling effect, thereby substantially shortening the electron transport pathway and decreasing interfacial transmission impedance. In addition, the sulfur defects on the surface of MoS2 as the anchoring point of sulfhydryl groups promote the enrichment of thiols on the surface of the material and reduce the reaction barrier for sulfhydryl oxidation, thereby improving the catalytic performance. The prepared CNTs-IL-MoS2/SPE biosensor shows excellent l-cysteine sensing performance by electrochemical detection.