Preparation And Theoretical Study Of Ag-doped MoS₂ Nanomaterials

Molybdenum disulfide(MoS2)is a transition metal sulfide with a naturally adjustable band gap structure.Two-dimensional layered molybdenum disulfide is different from traditional bulk materials and has excellent electrical,optical and magnetic properties.In this paper,the electrical and optical properties of the material were controlled by doping.The pristine monolayer MoS2 and Ag-doped MoS2 nanomaterials were studied in terms of experimental preparation and theoretical calculation.In addition,the theoretical study of Sb-doped MoS2 was also carried out.In this paper,pristine MoS2 nanosheets and Ag-doped MoS2 nanosheets were synthesized by hydrothermal method.The thickness of nanosheets ranged from 0.9 to 1.1 nm.In addition,the UV-visible absorption test showed that the absorption spectrum of Ag-doped MoS2 nanosheets increased with increasing Ag content;What's more,the photocatalytic performance of Ag-doped MoS2 nanosheets were also tested.The results showed that the photocalalytic hydrogen production rate of Ag-doped MoS2 nanosheets can reach 2695 umol h-1g-1 and has good stability.At the same time,the dielectric function,absorption coefficient,refractive index and electronic structure of undoped pristine and Ag-doped monolayer MoS2 were studied by density functional theory.The simulation results showed that the absorption intensity of the Ag-doped MoS2 structure in the UV-visible regions was significantly enhanced,and the conduction band of the Ag-doped monolayer MoS2 system was lower than that of the pristine MoS2.Therefore,Ag-doped MoS2 can optimize the energy band structure to enhance photocataltic activity.The above studies show that the experimental test is consistent with the theoretical calculation results.The electronic structure and optical properties of pristine MoS2 and Sb-doped monolayer MoS2 were studied based on first principles.The results showed that the pristine MoS2 and Sb substitution Mo-doped monolayer MoS2 were direct bandgap semiconductors with band gaps of 1.68 eV and 1.06 eV,respectively.However,Sb substitution S-doped monolayer MoS2 was an indirect bandgap semiconductor with a band gap of 1.47 eV,so doping Sb can better control the energy band structure of MoS2.The energy width of the absorption spectrum of MoS2 after Sb doping was significantly broadened and the absorption was obviously enhanced.These theoretical results are expected to provide useful guidance for the design of monolayer MoS2-based optoelectronic nanodevices.