The Systhsis Of MoS₂ Based Composites And Their Photo-and Electro-catalysis Performance

To tackle the increasing crisis of the environmental issues and energy shortage,researchers are looking for novel materials to improve the effeiceny of energy conversion and pollutant degradation.Two-dimensional layered materials,as the popular star materials,are favorable for these applications and molybdenum disulfide with unique advantages has attracted much attention in research of theinorganic materials.This paper focuses on improving the performance of solar cell and the degradation of the pollutants taking advantage of the catalytic properties of molybdenum disulfide composites.The main work including the following sections:（1）An in situ hydrothermal method was employed to vertically grow Few-layer MoS₂（3-5 layers）sheets on three dimensional graphene.Oxygen atom was spontaneously incorporated into the MoS₂ layer due to the inert M-O bonding from the precursor and the abundant oxygen-content groups distributed on the graphene oxide sheet,which reduces the bandgap and improves the conductivity and catalyzing activity of the MoS₂.In addition,the three dimensional composite（3D-G/MoS₂）exhibits good mechanical strength,interconnected electron transfer network,high surface area of 117 cm2g-1,and multi-level porous structures from micro-to macro-scale,which could enhance the charge and mass transport when used as counter electrode for quantum dot sensitized solar cells.Therefore,an optimized power conversion efficiency of 4.13 % was demonstrated,indicating ⁶3 % and ³4 % enhancement compared with Pt and pure MoS₂ counter electrode.（2）MoS₂/graphene hybrid porous films were directly deposited on fluorine-doped tin oxide（FTO）conducting substrates with a hydrothermal method.The graphene portion,which was found to have great influence on the Cell performance,could be simply manipulated by adjusting the initial GO dosages.The as-prepared MoS₂/graphene hybrid counter electrode delivered a power conversion efficiency of 7.63 %,which was superior to Pt-based（7.01 %）and pure MoS₂-based（6.68 %）DSSCs.Based on the electrochemical investigation,the enhanced performance could be ascribed to the improved electrical conductivity,catalytically active sites,and electrolyte diffusion rate of the MoS₂/graphene hybrid counter electrode.（3）The hydrothermal method was used to producethe MoS₂ and BiOCl exposing high activity（001）surface.The heterostructures of the two nanomaterials could be formed by ultrasonic irradiation.It was found that MoS₂ can increase the light absorption efficiency and reduce the band gap of BiOCl,which increases the degradation efficiency of the RhB solution.Meanwhile,Bi atoms on the surface of the BiOCl,forms Bi-S bonds with the S atoms on MoS₂,which effectively enhances the electron transfer at the interface.The MoS₂ and BiOCl dosages were altered to explore the optimal ratios.When the content of Mo S₂ is 0.5 %,the fastest degradation could be achieved.Different holes and electrons capture agents were added to confirm that the catalytic degradation origin from the photogenerated hole.