Study On Controlled Construction And Electrocatalytic Hydrogen Analysis Based On Transition Metal Tungsten And Vanadium Nanoporous Films

Energy consumption and environmental degradation are two problems facing the development of the world today.There is an urgent need for a new energy source to replace traditional fossil energy fuels,and people are committed to finding a new energy alternative.Hydrogen can be used as a perfect substitute for fossil energy because of its high energy density and renewable characteristics,and it is a clean energy.Water electrolysis provides a convenient way to produce hydrogen.According to reports,so far the promising electrocatalysts are still Pt based noble metal compounds.However the cost of noble metals is expensive because of its small amount on the earth.Therefore,effective,low-cost,non-inert catalysts with abundant earth reserves are still very important for clean hydrogen energy systems.In response to this problem,we use the transition metal compound with the unique structure of the nanoporous film as the substrate.We load the active component material or introduce internal defects through anion doping to improve the catalytic activity of the catalyst.This is used for the electrochemical hydrogen evolution reaction,the morphology and structure characterization and electrocatalytic analysis are carried out.The specific contents are as follows:(1)We have synthesized the WN(Ru@WN)nanoporous film catalysts loaded with ruthenium nanoclusters in situ by anodic oxidation,hydrothermal reaction,and CVD nitriding on tungsten foil for hydrogen evolution reaction under acidic and alkaline conditions.Compared with the pure WN without supporting ruthenium clusters,the three-dimensional nanoporous Ru@WN with a highly self-supporting structure exhibits significantly enhanced HER activity in a wider range of pH electrolytes.Generally,the best catalyst prepared in 0.5 M H₂SO₄and 1.0 M KOH electrolyte has a small overpotential of 65 and 70 mV when the current density is 10 mA cm^-2,and has excellent electrocatalytic performance.In addition,the obtained electrocatalyst exhibits a lower Tafel slope and good long-term electrochemical stability in both solution environments.Due to the effective synergy between the active center Ru nanoclusters and the WN nanoporous film support,the catalyst has significant HER catalytic activity and excellent stability.(2)We have prepared anion-doped V(Se_xS_1-x)₂nanoporous film catalyst on vanadium foil by using anodic oxidation and CVD selenium/sulfide methods,which can be used for hydrogen evolution reaction under alkaline conditions.Compared with nanotubes and nanowires,this nanoporous structure has a higher active specific surface area.The self-supporting nanoporous structure material with a open framework can show more exposed edge positions and provide more active sites.At the same time,the internal defect structure introduced by anion doping serves as the active center,which better improves the catalytic activity and effectively enhances the hydrogen evolution reaction kinetics.