Nano-sensor Based on MoS2 Nanosheet mixed with Au quantum dot: Role of Layer Number and Temperature

The performance of nano-sensor based on MoS2 nanosheet mixed with Au particle is tested based electrochemical test involving cyclic voltammogram and impedance spectroscopy, where the Fe-III(CN)(6)(3-)/Fe-II(CN)(6)(4-) and dopamine (DA) are chosen as research object to verify the role of layer number of MoS2 nanosheet and the temperature. The electrochemical test shows the Au nanoparticle would improve the electron exchange reaction occurring on the electrode. In the solution of Fe-III(CN)(6)(3-)/Fe-II(CN)(6)(4-), the electrode reaction follows FeIII) open=(CN63-+e--> MoS2FeII<) open=(CN64-, where increasing the layer number of MoS2 nanosheet would restrict the reaction. In the DA system, the reaction of DA -> MoS2DOQ+2H++2e- occurs on the electrode and increasing the layer number of MoS2 nanosheet would facilitate the reaction. The difference as mentioned above is assigned to the energy level shift originated from variance of layer number of MoS2 nanosheet and the changing of reaction mechanism. In addition, temperature would mainly facilitate the kinetics of electron exchange reaction, which is assigned to the diffusion acceleration of DA molecule. Simultaneously, the desorption process of reactant in the electrolyte would enhance. The role of layer number of MoS2 nanosheet and the temperature is clarified with the thermodynamic and kinetic properties of electron exchange reaction based on MoS2 nanosheet, which would improve the understanding of nano-sensor based on MoS2 nanosheet.