Development And Application Of Theoretical Methods Based On First Principles In Hydrogen Electrocatalysis And Potassium Ion Storage

With the development of society,the renewable energy is more and more important for human society.In recent years,with the rapid consumption of fossil fuels and the ever-increasing energy demand,the renewable energy sustainable supply is important for the development of human society.Electrochemical hydrogen evolution reaction and secondary ion battery are two energy storage and conversion methods with great research significance in the direction of new energy.The current commercial electrolysis water hydrogen evolution reaction catalyst is mainly platinum-based materials,but its high price and scarcity of reserves have severely restricted the development of this industry,so the design and preparation of cheap and highly active electrocatalysts is a hot issue in this industry.For energy storage equipment,as the demand for energy storage in human society continues to increase,it is difficult for traditional lithium-ion batteries to support the future energy storage market,so the development of new energy storage equipment is extremely important.The problem of rational design of catalyst materials or energy storage materials involved in it depends on the micro-atomic scale image of the corresponding process.For this,because experimental spectroscopy is more limited in electrochemical systems,it relies heavily on theoretical calculations based on first principles.In this paper,two works are carried out for the application of the first principles method in the electrocatalysis and energy storage directions.The full text is divided into two parts:（1）In the direction of electrocatalysis,we try to modify and develop the popular Norskov method from a theoretical level.We consider that the Norskov method is derived from the traditional heterogeneous catalysis,and the influence of electric potential is not considered naturally.Therefore,we should try to add electric potential to it more accurately.Based on this idea,we took hydrogen electrocatalysis as an example,developed and constructed a new type of two-dimensional electrocatalytic active volcano,and named it the"volcanic belt"model.In this volcanic belt model,the catalyst has changed from a“point”on a traditional volcano to a“curve”as it is now.We have studied the potential-dependent behavior of this curve and found that it is easy to simplify into a straight line in form.We call this straight line the"simplified catalyst trajectory（s CT）".s CT can react well with the potential-dependent adsorption energy derived from the lateral interaction,and can well describe the asymmetry of the positive and inverse reactions of hydrogen evolution and hydrogen oxidation.Finally,we take the hydrogen evolution（HER）/hydroxide（HOR）reaction on Rh₂P and Rh as an example to illustrate the application of the"volcanic belt"model.（2）In the direction of energy storage,we try to apply first principles to guide the experiment.Based on the predictions calculated by density functional theory（DFT）,we found that Se/N co-doped carbon materials can effectively store potassium ions,so we developed a simple and universal self-sacrificial template method to prepare Se and N co-doped The heterogeneous three-dimensional（3D）macroporous carbon（Se/N-3DMp C）,which has a hierarchical porous structure and abundant active sites,can enhance the pseudocapacitance activity and kinetics of the anode for potassium ion storage,and enhance the cathode for potassium ion Capacitive performance of storage.As expected,PIHC with an operating voltage of up to 4.0 V can present a high energy density of 186 Wh kg^-1(at a power density of 8100 W kg^-1)and superior long-cycle performance.Through the above research,we have explored the reaction mechanism of the electrocatalyst for the hydrogen evolution reaction based on the first principles,and constructed a new type of volcanic belt containing electric potential information.At the same time,we design and synthesis a carbon-based material that can effectively store potassium ions and analyze the effect of heterogeneous atoms on the performance of potassium storage.The conclusion of this paper can present the research ideas and guiding ideas for the design and analysis of materials in the field of energy storage and conversion.