Study On Electrocution Hydrogen Evolution Materials Using Polyunsaturates As Precursors

In recent years,the search for a clean,efficient and recyclable energy has become an urgent problem due to the increase in global energy demand and the increasing energy crisis.As a new kind of energy,hydrogen is becoming more and more widely concerned.Hydrogenation is the most environmentally sustainable and environmentally sustainable way to produce hydrogen,but the reaction requires efficient catalysts.Pt-based noble metal materials are the most effective electrocution for the hydrogen evolution reaction?HER?.However,it is difficult to achieve industrialization because of the high price and resource scarcity.Therefore,it is of great significance to develop non-noble metal catalysts with low-cost and high abundance.Based on the non-noble metals molybdenum phosphate as the research object,using polyunsaturates as precursor,the guiding effect of the special structure of polyunsaturates and the advantages of small size synthesis molybdenum phosphide and to start a research on the electric performance of catalytic activity of hydrogen evolution.On this basis,a series of high efficiency,low cost and novel phosphating molybdenum hydrogen catalysts were designed to further improve the hydrogen production performance and adopt the strategy of material composition.Firstly,an"anchor-assembling"method was adopted for the Anderson structure of heteropolyacid?NH₄?₄[NiMo₆O₂₄H₆]·5H₂O as a precursor,polyethylenimine?PEI?as a coupling agent,and different types of carbon-based materials(carbon Nanotubes,reduced graphene oxide,and N-doped in-situ carbon were used as carriers,and superacid-/carbon-based composites were assembled by using supermolecular weak interactions.Again,a"dispersion?wrapping?"strategy is used:to further achieve monodisperse and independence of polyacids at the molecular level.The surfactant cations as the main component,the polyanionic anion clusters as the enveloping guest,and the host-guest interactions assemble into the"Surfactant-Encapsulated Polyoxometalates?SEP?"to achieve polyacid in the molecule.Monodisperse and independent at the level.Using a method of temperature-programming,through the exploration of constant temperature and constant temperature,?NH₄?₄[NiMo₆O₂₄H₆]·5H₂O was used as the Mo source,and diammonium phosphate was used as the P source.The hydrogen/argon mixed atmosphere was adopted.Two-step synthesis of molybdenum phosphide nanocrystals with different carbon-based materials.The precursors and composites were characterized by multiple angles,including molecular structure,crystal phase,morphology and pore structure,and element distribution.The above materials were used as catalysts to characterize the hydrogen evolution performance of the catalysts.The results are shown at room temperature 0.5mol·L^-1H₂SO₄acidic solution is 292 mV;the initial overpotential of MoP/CNT catalyst is 106 mV,the Tafel slope is 57 mV·dec^-1;the initial potential of MoP/NC catalyst is 182 mV,the Tafel slope is109 mV·dec^-1;the initial overpotential of the MoP/RGO catalyst is 140 mV,and the Tafel slope is 37 mV·dec^-1.Anderson structure of?NH₄?₄[NiMo₆O₂₄H₆]·5H₂O heteropoly acid has a smaller size?<1 nm?and good water solubility,can provide a fixed ratio of bimetallic source Ni:Mo=1:6,forming Ni₂P and MoP composite crystal phase,Ni doping can effectively change the hydrogen bond energy,adjust the electronic structure of the material,and reduce hydrogen's empty d orbital.Based on the above characteristics,the hydrogen production performance of the molybdenum phosphide nanocrystals using the?NH₄?₄[NiMo₆O₂₄H₆]·5H₂O heteropoly acid with Anderson structure as the precursor may be better.From the test results of catalytic performance,it can be seen that the introduction of carbon-based materials can greatly improve the electrocatalytic hydrogen production performance of molybdenum phosphide catalysts.This is because the carbon-based material has a large specific surface area and high electrical conductivity,and has an interaction with the molybdenum phosphide nano-particles,which can effectively improve the dispersibility of the molybdenum phosphide nano-particles and expose more The catalytic active site.In addition,the study also found that nitrogen-doped in-situ carbon cladding can exhibit higher catalytic performance.This is due to the introduction of N.On the one hand,C-N species are formed.This species can also serve as the active center for hydrogen production.Promote the progress of the reaction.On the other hand,N is more favorable to H⁺than C,so the reaction is easier to perform.