Syntheses Of Metal Sulfide/Mesoporous Carbon Composites And Their Electrocatalytic Hydrogen Evolution Properties

At present,energy shortage and environmental problems are becoming more and more serious,so it is very important to reduce the dependent of society on traditional fossil fuels.It is also a subject that human beings must explore and study first.Hydrogen energy is considered as the most promising candidate energy to provide clean energy in the future because of its non-toxic,high stability,environmental friendliness and high energy density.Compared with other methods for preparing hydrogen,electrolytic aquatic hydrogen has attracted more and more attention because it does not need to use carbon based fuel,high efficiency and simple operation.However,electrolytic water has the disadvantage of excessive energy consumption.The use of efficient catalysts can reduce energy consumption.Although the catalytic effect of platinum-based catalysts is the best,due to the high price,it is urgent to find a cheaper and more efficient electrocatalytic hydrogen evolution catalyst.In this thesis,metal sulfide/mesoporous carbon composites were prepared by simple methods.These composites have the advantages of low cost,high mechanical stability and easy preparation.In this thesis,its composition,structure and hydrogen production performance are further analyzed and studied.Mainly includes the following three parts:1.Melamine-formaldehyde(MF)resin containing Co Cl₂was synthesized by solvent volatilization induced self assembly(EISA)method.It was mixed with thiourea,ground and carbonized at high temperature,and then pickled to obtain cobalt nitrogen sulfur Co-doped mesoporous carbon material.The characterization results show that the final product has mesoporous structure.The H₂S produced by high temperature decomposition of cobalt ion and thiourea generates Co₉S₈,and Co₉S₈nanoparticles are evenly dispersed in the composite,And N and S atoms are also doped into the carbonaceous matrix.Sample MF4.0T6.0,showing the best catalytic activity at full p H and good stability.2.Cobalt nitrogen sulfur Co doped mesoporous carbon materials were synthesized by using salt as template.Firstly,MF resin containing Co Cl₂was prepared by solvent volatilization induced self-assembly method as precursor,thiourea as sulfur source,and Na Cl,KCl,Na Cl/KCl and Ca Cl₂as templates.The quality of the sample and the type of the salt that can be characterized can be determined by the porosity of the sample.MFCo S-Na Cl1.00 has the best electrocatalytic hydrogen evolution(HER)activity.In alkaline medium,when the current density is 10 m A cm^-2,the over potential is 116 m V and has significant stability.3.Mo,N,S co-doped Mo S₂/Mo₂C mesoporous carbon composites were prepared with glucose,thiourea and Mo O₃as precursors.Without complex steps,the precursor is mixed by manual grinding and carbonized under argon.There is no solvent in the whole process,which is very green and environment-friendly.According to the characterization,it can be proved that the product has mesoporous structure,and the different ratio of synthesis affects the specific surface area.Sample T2.0G4.0Mo1.0 under alkaline conditions,the initial over potential is 111 m V,and the over potential at current density of 10 m A cm^-2is 183 m V,which has good stability.The interface between Mo S₂and Mo₂C is considered to improve the electrocatalytic activity.