Study On Preparation And Electrochemical Hydrogen Production Performance Of MOFs/SnS₂ Composite Materials

The depletion of energy has caused long-term problems for human,and hydrogen energy as a new type of energy source may become one of the mainstream energy sources in the future.The electrocatalytic hydrogen analysis has the characteristics of good stability,equipment simplicity and fresh and pollution-free,which has attracted much attention in recent years.Despite the excellent electrolysis of valuable platinum metal resources,the resource shortage and expensive prices make us to seek alternative electrocatalysts.In recent years,tin disulfide(SnS₂)has gradually entered the human view,due to its unique layered structure and large specific surface area,and its active site can be regulated by phase transition and doping with other substances.MOFs are 3D frame materials composed of metal ions and organic ligands and have a wide use in the catalytic field due to the characteristics of them that can expose more active sites than the surface area.In this paper,SnS₂ nanosheets were prepared by hydrothermal method.The effects of different sulfur sources,tin sources and p H on the electrochemical hydrogen evolution performance were studied.The electrochemical hydrogen evolution performance was characterized by XRD,SEM and TEM.The characterization results show that SnS₂(S8-N)prepared with thioacetamide and siric acid and weak base containing little citrate acid had higher crystallinity,large specific surface area and better morphological characteristics which compared with the other SnS₂ samples.Electrochemical performance tests show that S8-N has a low overpotential(158 m V),a smaller Tafel slope(180 m V·dec^-1),a double-layer capacitance of 3.58 m F·cm^-2,good electrocatalytic stability and a lower resistance.To further improve the ability of SnS₂ to electrocatalytic hydrogen evolution performance,HKUST-1/SnS₂ and Ni-MOF/SnS₂ materials were prepared from SnS₂and Cu-1,3,5-Benzenetricarboxylic acid metal organic framework(HKUST-1)or Ni-2-Methylimidazole metal organic framework(Ni-MOF)by stir synthesis method and grinding method,respectively.Both composites were characterized by XRD,SEM and TEM and tested for electrocatalytic hydrogen evolution performance.Compared with the pure SnS₂ nanosheets,HKUST-1/SnS₂and Ni-MOF/SnS₂composites showed improved electrocatalytic hydrogen compared to pure SnS₂nanosheets with low overpotential(HKUST-1/SnS₂:142 m V and Ni-MOF/SnS₂:117m V),small Tafel slope(HKUST-1/SnS₂:157 m V·dec^-1,Ni-MOF/SnS₂:163m V·dec^-1),large double-layer capacitance(HKUST-1/SnS₂:8.0 m F/cm~2,Ni-MOF/SnS₂:11.5 m F/cm~2),good electrocatalytic stability and lower resistance.