| Due to the depletion of fossil energy sources and the environmental pollution caused by their use,the development of new energy sources to replace fossil energy sources is currently a matter of importance for all countries in the world today.As one of the alternative energy sources,hydrogen has the advantages of higher calorific value,abundant in reserves,no additional pollutants during its use.It is also pollution-free during the production using water electrolysis.Combining hydrogen from electrolysis with other renewable energy sources such as solar,wind and tidal energy,the problem of energy fluctuations over time can be solved in the form of reserve energy.However,the electrolytic water industry is currently experiencing bottlenecks,and the development of electrolytic water is limited by the use of precious metal-based catalysts to assist the process.Replacing precious metal catalysts with low-cost and high-performance catalysts is currently a major research direction for researchers.In order to prepare catalysts with excellent performance,this paper focuses on self-supporting transition metal sulphide catalysts as the main direction.The catalyst performance was enhanced by selecting excellent precursors as templates and using plasma assisted nitrogen doping to induce interface and defects.（1）Nitrogen-doped Co3S4/Fe7S8 nanosheet catalysts were synthesised by in situ growth on Co Layered Double Hydroxide（Co LDH）nanostructures anchored to cobalt foam,subsequent Fe ion exchanging to introduce Fe elements,and finally nitrogen plasma treatment of the sulphated samples.The nitrogen-doped catalysts further enhanced the excellent performance of cobalt and iron sulphide with a HER overpotential of 26 m V at a current density of 10 m A·cm-2,a reduction of 33 m V compared to a commercial Pt/C electrode,and an overpotential of 230 m V in the OER reaction at the same current density,a reduction of 60 m V compared to a commercial Ru O2 electrode.The nitrogen-doped Co3S4/Fe7S8 was used as bifunctional electrocatlyst for overall water splitting in alkaline solution in a two-electrode system as both the anode and cathode electrodes.It exhibits lower potentials of 1.61 V and 1.80V at 10 m A·cm-2 and 50 m A·cm-2 current densities,respectively.（2）Fe-doped Co3S4/Mo S2 catalysts were synthesised using ZIF-67（Zeolitic Imidazolate Frameworks）grown in situ on cobalt foam as a subsequent synthetic template,inducing crystal defects by partial Fe ion exchange,and finally by introducing Mo elements during the sulphidation process.The catalysts showed excellent overpotentials of 90 m V and 243 m V during HER and OER reactions at a current density of 10 m A·cm-2.It also showed potentials of 1.42 V and 1.71 V at 10 m A·cm-2and 100 m A·cm-2 current densities,respectively.Finally,it also showed excellent capability in long-term stability tests. |
