| The storage of fossil energy is constantly decreasing,and the energy crisis will be an inevitable challenge.Therefore,the technology of hydrogen production by electrolysis of water has received widespread attention.However,noble metals(Pt,Pd,etc.)have a significant effect on the production of hydrogen from electrolyzed water,but their low reserves and high cost limit their large-scale commercial applications.As a typical transition metal material,Mo S2 has widely used as a hydrogen evolution reaction(HER)catalyst because the hydrogen adsorption energy at the edge of the Mo atom is similar to that of metal Pt.However,the surface inertness of Mo S2 is attributed to the accumulation of van der Waals forces existing between its layers,which masks the number of active sites and limits its catalytic activity.The purpose of this paper is to overcome the shortcomings of Mo S2.Based on Mo S2@carbon cloth composite materials,the composite materials were prepared through the strategic design of nitrogen doping,carbon wrapping,and introduction of vacancies,and to explore the electrical properties of the prepared catalysts.Catalytic performance.The work content of this article is as follows:(1)N-doped C-wrapped N-doped MoS2/carbon cloth composite material(N-C@N-Mo S2/CC):hydrothermally generated dopamine-coated Mo S2/carbon cloth composite material at 200°C,and then the final sample was obtained by heating in an argon atmosphere tube furnace to 700°C for 4 hours.The composite materials synthesized with different content of dopamine precursors have different catalytic activities.From the experimental results,it can be concluded that the introduction of dopamine not only changed the appearance of Mo S2 but also adjusted its electronic structure,effectively improving the catalytic hydrogen evolution performance of the composite material.When dopamine is 75 mg,the catalytic performance of N-C@N-Mo S2/CC is optimal,with an overpotential of 174 m V at a current density(m A cm-2)of 10,and a Tafel slope of 75 m V dec-1,Moreover,the current density has only a slight attenuation(3.43 m A cm-2)after 100000 s at a fixed overpotential,showing superior electrocatalytic performance.(2)Ultrahigh defective MoS2/CC composite material(Uh D-Mo S2/CC):Using zinc acetate as the precursor,the Zn-doped Mo S2/carbon cloth composite material was synthesized in one step by hydrothermal method,and then the zinc phase was removed by soaking in acid to obtain the Mo S2/carbon cloth composite material with many sulfur vacancies.When Zn is doped with Mo S2,Zn S will be generated and certain sulfur vacancies will be formed.Then when the Zn phase is removed by the acid soaking method,more sulfur vacancies will be generated,thereby increasing the electrocatalytic activity of the material.At the same time,when exploring the effect of different content of zinc acetate on the catalytic performance of Mo S2/carbon cloth,experiments show that the catalytic performance of the composite material is the most significant when the zinc acetate is 0.2 g.It has a Tafel slope of only 55 m V dec-1,internal resistance of 3.5?,and catalytic stability of 33.3 h,showing superior hydrogen evolution performance. |
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