| Ever-increasing consumption of fossil fuels causes major societal and environmental issues.Therefore,seeking and developing sustainable and clean energy to replace traditional energy sources has become an urgent problem.Hydrogen,due to its zero carbon emission and high gravimetric energy density,is considered as an ideal replacement for fossil fuels Electrocatalytic water splitting is an effective approach to produce hydrogen.Currently,noble metal Pt-based materials are benchmark electrocatalysts for hydrogen evolution reaction(HER).However,their high cost and scarcity prevent large-scale applications in the renewable energy field.Hence,developing non-precious,low-cost metal based electrocatalysts is on the agenda.In this paper,two-dimensional transition metal Ni/Co(nickel-cobalt)foam was used as the substrate,and nano-transition metal selenide was constructed on the surface of nickel-cobalt foam by atmospheric pressure dielectric barrier discharge(DBD)and electrodeposition method and hydrothermal method.The hydrogen evolution(HER)and oxygen evolution(OER)properties and electrochemical stability were studied.The internal structure of the nanocrystals was characterized to explore the intrinsic relationship,and the important factors affecting the electrocatalytic activity of transition metal selenides were investigated.The content is as follows:(1)The MoSe2-NiSe2-CoSe2/PNCF multiphase trimetallic nanorods were prepared by nickel-cobalt foam(NCF)as the matrix by atmospheric pressure dielectric barrier discharge(DBD)and two-step hydrothermal method.The characterization analysis shows that the diameter of MoSe2-NiSe2-CoSe2 nanorods is about 240 nm,the 1T-2H mixed phase of MoSe2 and the synergistic effect of custom morphological design make hydrogen of MoSe2-NiSe2-CoSe2/PNCF in alkaline medium.The release reaction(HER)has high electrocatalytic activity and stability.In the KOH electrolyte with a concentration of 1 M,the overpotential of MoSe2-NiSe2-CoSe2 is only 38 mV at a current density of 10 mA cm-2,and the hydrogen evolution is as high as 2.6 mmol h-1 cm-2.The efficiency is much higher than most reported transition metal based electrocatalysts.In addition,MoSe2-NiSe2-CoSe2 exhibits excellent stability at high voltage at the same time.After 10,000 cycles of CV cycle and 100 hours of it test scan,its physicochemical crystal structure has not changed greatly in nature,and has great potential in industrial applications.(2)Through the surface pretreatment(Cu@PNCF)of atmospheric pressure dielectric barrier discharge and Cu electrodeposition of nickel-cobalt foam(NCF),a large number of fine cracks are generated on the surface of the material,and micro-nano structures of NiO,CoCx and Cu are formed on the surface of the substrate.Then,the electrocatalytic activity of HER and OER by the Cu3Se2@CoSe2-NiSe2/PNCF nanosheet prepared by one-step hydrothermal method is greatly improved.Based on the increase of specific surface area of the substrate,high electron transfer rate and in-situ growth,Cu3Se2@CoSe2-NiSe2/PNCF has excellent activity and stability in electrocatalysis.At a current density of 10 mA cm-2,the overpotentials for hydrogen evolution and oxygen evolution were 43 mV and 240 mV,respectively,while the amount of hydrogen evolution and oxygen evolution were 1.5 and 0.9 mmol h-1 cm-2,respectively.It should be specially stated that in the 1 M KOH electrolyte,when the test current density is 100 mA cm-2,the physical structure of Cu3Se2@CoSe2-NiSe2/PNCF does not change greatly after 50 h HER reaction.Excellent electrocatalytic stability and great application potential. |
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