Study On Electrocatalytic Hydrogen Evolution Performance And Mechanism Of Two Dimensional Material Moving Electrode

Hydrogen energy as a sustainable clean energy has been widely concerned.Hydrogen has the highest enthalpy of all known energy sources:142 MJ kg^-1,and the only product of hydrogen combustion is clean water.Hydrogen is the most convenient energy carrier in the future long-term energy storage system.The conversion of chemical energy stored in hydrogen into electric energy can be completed directly in the fuel cell,which can achieve a power generation efficiency of up to 70%.Electrocatalytic water electrolysis is one of the simplest methods for hydrogen production.With the increasing demand for renewable energy,the development of efficient water electrolysis system is very important for the development of hydrogen energy.In general,constant voltage or constant current electrolysis is used to produce hydrogen from water electrolysis.However,this electrolytic method has low electrode stability and low hydrogen production rate,so there are still some challenges in its wide application.And the adhesion of hydrogen bubbles to the electrodes severely hindered the efficient production of hydrogen.Dynamic electrochemistry can apply dynamic energy to the electrochemical system and regulate the surface interface of the catalyst,which is expected to be used to improve the hydrogen generation rate.The research content of this paper mainly includes the following two parts:（1）In Chapter 2,we introduce a moving electrode into the traditional water electrolytic system,and use the moving electrode to improve the hydrogen generation rate and study its mechanism.We use Mo S₂catalyst as a model catalyst to make a moving electrode connected with a linear motor and study the electrocatalytic hydrogen evolution performance of the moving electrode.The contact time between electrode and electrolyte can be changed by periodic movement of moving electrode,and the problem of electrode interface can be changed.By exploring the difference of the speed and frequency of the moving electrode and the hydrophilicity of the electrode material,the results show that the amount of charge input into the electrolytic cell will increase in different degrees compared with the constant electrode condition,thus improving the hydrogen production rate.When the speed of the moving electrode is 90 mm/s,the amount of charge accumulated by the moving electrode for 1 hour is twice of that under the condition of constant electrode,and the rate of hydrogen production is 2.4 times of that under the condition of constant electrode.When the frequency of the moving electrode was changed to 5 s,the amount of charge accumulated by the moving electrode in 1 hour was twice as high as that under the constant electrode condition,and the hydrogen production rate was 2.1 times as high as that under the constant electrode condition.The hydrophilicity of the catalyst was changed.When the catalyst was hydrophobic,the amount of charge accumulated in 1 hour was 4.9 times of that under the condition of-0.1 V low pressure,and the hydrogen production rate was 2.1 times of that under the condition of constant electrode.The results show that with the introduction of moving electrode,the amount of charge input into the electrolytic cell will increase in different degrees compared with the constant electrode condition,and the hydrogen generation rate can also be significantly improved.The electrolysis system with moving electrode is introduced to improve the hydrogen generation rate of HER by changing the surface state when the electrode and electrolyte contact.When the voltage is applied in the dynamic electrolytic system,the peak current generated by the double electric layer formed on the interface of the electrolyte and electrode is much larger than that generated by the constant electrode electrolysis.The amount of charge accumulated in the dynamic electrolytic system is further increased and the rate of aquatic hydrogen electrolysis is finally increased.With the movement of the moving electrode,the adhesion time of hydrogen bubbles on the electrode can be shortened and the generated hydrogen bubbles can be removed in time.（2）On this basis,Chapter 3 explores whether the use of moving electrodes to increase the rate of hydrogen production is universal.We further studied the electrochemical properties of Pt-Mo S₂ and Mo₂C catalysts as moving electrodes.When different catalysts are used as moving electrodes,the electrocatalytic hydrogen generation rate can be improved effectively.When the voltage of-0.1V is applied and the speed of the moving electrode of Pt-Mo S₂ is 90 mm/s,the amount of charge accumulated by the moving electrode at 1800 s is 2.4 times that of the constant electrode condition,and the hydrogen production rate is 4 times that of the constant electrode condition.The amount of charge accumulated by Mo₂C moving electrode at600 s is 1.9 times of that under constant electrode condition,and the rate of hydrogen production is 2.4times of that under constant electrode condition.The study of electrocatalytic hydrogen evolution using different catalysts with moving electrodes shows that this method has a certain universality and can significantly improve the hydrogen production rate of electrolytic water.This work provides an effective method for improving the hydrogen evolution activity of electrocatalytic water electrolysis by using the moving electrode technology,and provides a new research idea and theoretical basis for the construction of a new electrolytic system.