Study On The Organic Liquid Phase Synthesis And The Electrocatalytic Hydrogen Evolution Properties Of Ni₂P/RGO And MoSe₂/CNTs Nanocomposites

Electrocatalytic hydrogen evolution（HER）is an environmentally friendly and sustainable technology for hydrogen production,but the lack of cheap and efficient catalysts limit their wide applications.Transition metal phosphides and dichalcogenides have high intrinsic catalytic activity and good stability,and are expected to be a substitute for precious metal Pt based catalysts.Carbon materials have large specific surface area,good electrical conductivity and resistance to acid and alkali corrosion.When carbon materials are combined with the catalyst,more active sites of the catalyst can expose,which can accelerate the electron transfer,thus improving the catalytic hydrogen evolution performance of the catalyst.In this thesis,homogeneous nickel phosphide（Ni₂P）nanoparticles and molybdenum selenide（MoSe₂）nanosheets were synthesized by using organic liquid phase methods and combined with reduced graphene oxide（RGO）and carbon nanotubes（CNTs）by different recombination methods,respectively.Electrocatalytic hydrogen evolution performance of the materials was tested.The main conclusions are as follows:（1）Using Ni acetylacetonate as a precursor,oleylamine as a solvent and trioctylphosphine（TOP）as a phosphorus source,uniform and pure phase nanoparticles of Ni₂P were synthesized.The effects of reaction temperature,TOP content and heating time were investigated,and a mature and stable synthetic route has been developed.A series of Ni₂P/RGO composite catalysts were prepared by ultrasonic self-assembly of Ni₂P nanoparticles and two-dimensional layered GO materials.After testing the HER performance,it was found that RGO could effectively improve the HER performance of Ni₂P nanoparticles,and the HER performance were optimized when the mass ratio of Ni₂P nanoparticles to GO was 2:1.The onset overpotential is only 105 mV and requires an overpotential of 195 mV and 269 mV to drive a current density of 10mA cm^-2 and 40mA cm^-2,respectively.The Tafel slope is 78 mV dec^-1,better than that of the Ni₂P nanoparticles tested under the same conditions.（2）Using molybdenum carbonyl and selenium powder as precursors,octadecene as a solvent,Mo Se₂ nanosheets were grown on carbon nanotubes in situ.The MoSe₂/CNTs composites with uniform morphology and stable structure were obtained by adjusting the ratio of carbon nanotubes.The growth mechanism of MoSe₂ nano sheets on carbon nanotubes was obtained by means of TEM and X-ray diffraction analysis at different stages of the reaction.The HER performance were tested toward a series of MoSe₂/CNTs catalysts.It was found that when the content of CNTs was 38.98%,the overpotential of 164 mV and 222 mV was required when drive a current density of 10mA cm^-2 and 40mA cm^-2,respectively.The Tafel slope is only 78 mV dec^-1.