Synthesis And Electrochemical Performance Of Molybdenum Disulfide Thin Films

Since 1965, the United States began to develop hydrogen engine, hydrogen is a fuel of high standing in the field of space position and no one could replace it until now. With the urgent needs of environmentally friendly and sustainable economic configuration, hydrogen fuel or hydrogen fuel cell, for the development of railway locomotive and car, has become very active. Pt metal is the most efficient hydrogen electrode catalyst and can realize HER(Hydrogen Evolution Reaction), and the voltage is very close to the thermodynamic reaction electric potential. However, precious metals are scarce resources, which could not meet the real needs of large-scale hydrogen production. Based on this situation, the development of a stable and efficient non Pt catalysts(including metal oxide, sulfide, phosphide, carbide and nitride) has become the main objective of the current HER research.Molybdenum disulfide has the similar hydrogen atom binding energy of Pt atoms, the structure of molybdenum can be adjusted and the price is low. So molybdenum has become HER research focus and is expected to be the alternative of Pt based electrocatalysts.The research object of this paper was molybdenum disulfide. First,ammonium tetrathiomolybdate coating solution was prepared, then ammonium tetrathiomolybdate film was transformed to MoS2 film by heat treatment. The experiment used X-ray diffraction, infrared spectroscopy, contact angle tester,optical microscope, scanning electron microscopy, atomic force microscopy,transmission electron microscopy and electrochemical workstation to test the samples. The mechanism and preparation method of molybdenum disulfide had been studied and got the results as follows:(1) With ammonium molybdate and ammonium sulfide as precursor,ammonium tetrathiomolybdate was preparation by heating, dissolving, stirring,and cooling crystallization. The prepared ammonium tetrathiomolybdate crystals had high purity, met requirements as a precursor of MoS2.(2) An uniform ammonium tetrathiomolybdate film was prepared on piranha solution treatment SiO2/Si substrate by dip coating ammonium tetrathiomolybdate solution.(3) Vacuum heat treatment conditions were not suitable for the growth of MoS2 in this experiment, the heat treatment time of 1000℃ had great influence on MoS2 film growth. With the extension of heat treatment time of 1000 ℃,MoS2 triangles gradually grew up and formed continuous film.(4) MoS2 film could be successfully transferred to the target substrate from the growth substrate using polystyrene(PS) as an auxiliary film.(5) The MoS2 film transferred to glassy carbon electrode had an electrocatalytic hydrogen evolution performance in 0.5 M H2SO4.