Synergistic effects of CNT-bridged dual-phase MoS2 on MXene as a ternary hybrid electrode for rapid sensing of chloramphenicol in aqueous media

Abstract

The fabrication of a hybridized electrochemical sensor denoted CNT/MoS2/MXene for chloramphenicol (CAP) detection is described based on growing MoS2 nanoflakes on stacked Ti3C2Tx MXene and bridging the structure obtained with carbon nanotubes (CNTs). Herein, we introduce an acid-etched stacked Ti3C2Tx MXene as an interlayered structure to accommodate solvothermally grown layered MoS2 and a bridged CNT network for the efficient electrocatalytic sensing of CAP. The successful growth of MoS2 on the MXene surface prevented restacking of layered MXene and increased conductivity. Interconnected CNTs over the MoS2 nanoflake array served as an electron transport highway, accelerating the electron transport pathway and maintaining the structural stability of the MXene/MoS2 heterostructure. Morphologically, CNT/MoS2/MXene was found to have a functionalized multilayered structure and to have a greater electron transfer rate, and a larger electrochemically active surface area than the binary feature. Modifying the surface area of MXene with MoS2 and CNTs synergistically enhanced the transportation of kinetic barrier electrons and well-defined the redox cycle in the ferricyanide system. Further, the electrochemical detection of CAP using a CNT/MoS2/MXene electrode by cyclic voltammetry (CV) produced greater electrochemical responses than bare GCE, MXene, CNT-MoS2, and MoS2MXene. In addition, scanning rates, the effects of different concentrations, and pH electrolyte tests showed that the GCE-CNT/MoS2/MXene electrode was suitable for the electrochemical sensing of CAP. Amperometric response, as determined by i-t profiles, showed the CNT/MoS2/MXene electrode had superior electrochemical sensing performance for CAP detection, a wide linear range (8 to 152 nM), a remarkably low detection limit (0.32 nM), a high sensitivity of 14.22 mu A nM- 1cm- 2, and superior stability (96 % activity retention after four weeks). The synergistic effect of the ternary three-dimensional assembly with CNT bridging over hierarchical MoS2/MXene increased surface-active sites and electron transportation rates and enhanced CAP detection performance. Moreover, the proposed sensor demonstrated high selectivity and satisfactory recovery for milk, eye drops, and pork.