Study On The Preparation Of Nickel Cobalt Nanocomposites And Their Properties For Allover Water Splitting

With the continuous deterioration of environmental problems,people have higher requirements for clean energy.Hydrogen energy is concerned because of its high calorific value and non-pollution.With the development of wind energy,geothermal energy,tidal energy and other clean energy,the technology of hydrogen production by electrolyzing water has been widely concerned again.Wind energy and other clean energy have regional and intermittent defects.Therefore,these surplus renewable energy can be used to convert it into hydrogen energy through the technology of hydrogen production by electrolyzing water,so its defects can be effectively overcome.Therefore,the research on process of water splitting is of great practical significance.To solve the above problems,researchers have done a lot of research work,mainly focusing on precious metals,transition metal sulfides,phosphates,selenides,hydroxides and other aspects in recent years.Among them,transition metal sulfides have attracted much attention because of their good conductivity,low cost and good electrocatalytic activity.Hydroxides have attracted many researchers'attention because of their abundant active sites and adjustable layer spacing.However,few researchers pay attention to the influence of fluid,core-shell structure and hydrophilicity on the material performance.In this paper,different hydroxides and sulfides with different structures were prepared by simple and efficient electrodeposition,hydrothermal method and solvothermal method,and a new type of collector was prepared.The hydrophilicity of the materials was controlled and the core-shell structure was prepared,and a variety of electrolytic water catalysts with excellent performance were obtained:1.?-Co?OH?₂ nanoflakes were electrodeposited on Ni coated metallized cotton fabric to prepare a metal/metal hydroxide composite electrocatalyst with her and oer properties.Ni-Co-30 shows high electrocatalytic activity and excellent stability of her and oer,and its oxygen evolution performance is similar to that of commercial RuO₂ catalyst.In addition,in1.0 M KOH electrolyte,Ni-Co-30 was assembled into cathode and anode in the total solution water and electricity cell.The assembled cell produced 1.64 V overpotential when the current density was 10 mA cm^-2,which indicated that the catalyst had a good application prospect.2.One dimensional Ni₃S₂ nanowires were prepared by solvothermal method,and an ultra thin two dimensional?-Co?OH?₂ was coated on the surface of the nanowires.Due to the formation of ultra-thin?-Co?OH?₂ on one-dimensional Ni₃S₂ nanowires,the core-shell structure of Ni₃S₂@Co?OH?₂ catalyst reduces the initial potential and over potential,improves the stability of the catalyst,and shows excellent electrocatalytic performance,which proves that it has high HER and OER catalytic activity,and can last for 100 h at a constant voltage of1.64 V under the current density of 10 mA cm^-2.The results show that the obtained Ni₃S₂@Co?OH?₂ has good catalytic stability in the process of total dehydration.3.0D-Fe-CQDs modified 3D-NiMoO₄ nanosheet arrays were synthesized on foam nickel by three-steps process containing hydrothermal,freeze drying and heat treatment.The physical characterization,such as SEM and contact angle test,showed that the surface hydrophilicity of NiMoO₄ nano tablets was improved because 0D-Fe-CQDs were evenly dispersed on 3D-NiMoO₄ tablets.Under the current density of 10 mA cm^-2,the HER and OER overpotential of Fe-CQDs/NiMoO₄/NF are 117 mV and 336 mV,respectively,which have showd this materal has good electrochemical properties.It shows that the high Faraday efficiency of electrolytic water catalyst can be improved by improving the hydrophilicity of different size composite materials.i...