The Preparation Of Binary Transition Metal Chalcogenides And Their Electrocatalytic Hydrogen Production

In present world,mankind is facing an unprecedented increase in energy demand.Simultaneously,looking for cleaner energy is also a topic that people are concerned about.So people are committed to finding the earth-abundant.cheap energy to reduce the dependence on fossil resources.Electrolysis of water to prepare hydrogen is a way to meet global energy needs and green hydrogen energy.The reason is that hydrogen as a clean and renewable energy,is considered to be the most potential and alternative energy to fossil energy sources.At present,there are many ways to prepare hydrogen,and electrolytic water preparation of hydrogen is the main way to produce hydrogen on a large scale.In the process of preparing hydrogen from electrolytic water,efficient electrode materials are essential.Therefore,the preparation of good electrocatalytic activity,low potential electrode material is the main work of people.Although Pt,Pd and other precious metals have a lower overpotential for hydrogen evolution reaction,but low abundance and high cost limits their use in large scale.Thus,it is important to study non-noble metals with high electrocatalytic activity.In recent years,transition metal oxides,carbides,sulfides,and selenides attracted much attention.In this thesis,NiMoO₄ nanowires arrays and Ni_0.85Se/MoSe₂ composites were prepared by hydrothermal method,and their microstructure and electrocatalytic hydrogen evolution were studied.The main contents of this thesis are as follows.1;The NiMoO₄ nanowires arrays were synthesized by hydrothermal method on the nickel foam substrate.The results of-electrochemical tests showed that the electrocatalytic activity of NiMoO₄ nanowires arrays was more obvious than the nickel foam substrate.In the alkaline electrolyte solution,to achieve j?10 mA/cm² requirements,over-potential of NiMoO₄ nanowires arrays is only 216 mV,while the nickel foam substrate requires 267 mV in order to achieve the same current density.The potential difference is 51 mV.The tafel slopes of NiMoO₄ nanowires arrays and nickel foam substrate are 109.74 mV dec^-1 and 155.82 mV dec-,respectively,under the same conditions.2:The NiMoO₄ nanowires arrays were selenized by hydrothermal method to prepare Ni_0.85Se/MoSe₂ nanocomposites and study their electrocatalytic activity.As a result of the process of electrolysis of water for preparation of hydrogen requires multi-step combination,including Volmer,Heyrovsky and Tafei three steps.So that the activity of the one-component electrochemical active electrode material in the process of electrochemical hydrogen production is limited.Therefore.we prepared Ni0.85sSe/NoSe2 composites to improve the electrochemical activity of the catalyst.The onset potential of Nio_0.85Se/MoSe₂ composites is 21 mV,the tafel slope is 83.74 mV dec^-1 and the electrode material exhibits good stability.This work offers a new methodology for the design and engineering of effective hydrogen evolution reaction catalysts.