Study On Modification Of ZIFs Bearing Transition Metal Derived Porous Carbon And Its Electrocatalytic Performance For Hydrogen Evolution

Pt-based precious metals are currently known catalysts with the best performance in the electrolysis of water for hydrogen evolution,but their expensive price limits their commercial applications.Therefore,the developments of low-cost and high-activity catalysts have become one of the research hotspots in the field of electrocatalytic hydrogen evolution.Zeolitic imidazolate frameworks（ZIFs）materials are widely used in electrocatalysis due to their large specific surface area,high nitrogen content and good stability.ZIFs are used as transition metal-porous carbon materials derived from precursors.Not only inherits the above characteristics,but also greatly improves the conductivity of the material,which will help improve the electrocatalytic performance.In this paper,based on the synthesis of ZIFs precursors,two catalysts for hydrogen production from water electrolysis containing transition metals are designed.The main contents are as follows:（1）Firstly,the double transition metal ZIF-67@ZIF-8 was synthesized in situ and used as a precursor,calcined and carbonized to obtain transition metal-derived carbon,and then introduced into the MoS₂ hydrothermal synthesis system to prepare MoS₂/Co Zn@C-800electrolyzed catalyst,the doping of Co,Zn and the formation of a carbon matrix not only improve the conductivity but also increase the active sites.Through the evaluation of HER test in alkaline electrolyte,the results show that when the calcination temperature of ZIF-67@ZIF-8 precursor is 800℃and the addition amount of Co Zn@C-800 is 40 mg,the MoS₂/40Co Zn@C-800 composite catalyst using foamed nickel as the substrate shows good hydrogen evolution activity.The overpotential measured at a current density of 10 mA/cm²is 129 mV,the Tafel slope is 99 mV/dec,the charge transfer resistance is the smallest,and the specific surface area of the electrical activity is maximum.（2）Using ZIF-67/Mo-MOF as a template,the ZIF-67/Mo-MOF is placed in the front end of the tube furnace into thiourea,and the transition metal sulfide Co_xS_y/MoS₂@C is obtained through a one-step in-situ solid-phase preparation method.The obtained sample not only maintains the nanostructure of MOFs and has more active sites,but also the residual porous carbon after vulcanization of MOFs improves the conductivity of the catalyst sample.When the vulcanization temperature is 600℃and the content of Mo-MOF is 50 mg,the catalyst Co₉S₈/50MoS₂@C-600 material has the best HER performance.The overpotential measured at a current density of 10 mA/cm² is 108 mV,the corresponding Tafel slope is 76mV/dec,the charge transfer resistance is the smallest,and the electroactive specific surface area is the largest.