Preparation Of Mesoporous Nickel Cobalt Oxide Materials And Their Applicatios In Electrochemical Of Cathode

Under the background of energy shortage and environment pollution,in today’s society,it is very urgent to develop the new alternative energy of fossil fuels.Hydrogen is recognized as the green energy to solve the shortage of resources and environmental pollution.It is the ideal secondary energy.Among numerous methods of hydrogen production,MEC has attracted the attention of scientific research scholars because of its many advantages.In this paper,the cathode materials of MEC using mesoporous SBA-15 as template were used as the focus in research.At the same time in a series of experiments,the effects of different impregnation methods,different nickel and cobalt salt ratios and different calcination temperature on nickel-cobalt oxide were discussed.Futhermore we compared the electrochemical performance of the prepared nickel-cobalt complex.The main work and conclusions are as follows:First,the effects of preparation methods on the photocatalytic activity of NiO catalyst and the electrochemical performance of MEC were investigated by using nickel nitrate as the nickel source.According to the data analysis,it was found that the NiO,prepared by double solvent method,maintain the mesoporous mesoporous structure under the action of hydrophobic solvent n-hexane.Futhemore,the mesoporous specific surface area（124 m2/g）and microporous area（189 m2/g）is much higher than other impregnation methods（mesoporous 80 m2/g,micropore 107 m2/g）.Relative to other methods,the double solvent method is benefit to the diffusion of the metal precursor to enter the microporous vias of SBA-15.The NiO electrode prepared by the double solvent method has the rich specific surface area of the active material due to the abundant micropores,and the rich active site of the active substance in the Faraday reaction,and the larger level of the channel provides a convenient channel for the electrolyte ion transport.Compared with several other methods,the catalyst prepared by the double-solvent method is the best in the electrochemical performance.Second,nickel-cobalt oxide with different molar ratios of nickel and cobalt was prepared by double solvent method.By means of XRD and N₂ adsorption,it can be seen that with the increase of nickel doping ratio,the a0 value of unit cell increases gradually,the peak of Ni O appears and gradually increases,and the peak of Co3O4 disappears.When the molar ratio of nickel to cobalt is 1: 2,the nickel cobalt spinel structure appeared,with Ni ions into the cobalt spinel lattice.The NiCo₂O₄ sample has a specific surface area of 100 m2/g and a microporous specific surface area of 78 m2/g.The high specific surface area and mesoporous pore structure result in the excellent electrochemical performance of NiCo₂O₄ electrode.The reason may be due to the special structure of spinel,which leads to the catalytic effect of hydrogen evolution than other ratio structure,the hydrogen content reaches 68.96%.The total reached 8.5 ml.Third,nickel cobalt oxide was prepared at different firing temperatures.At low temperature calcination（300℃）,NiCo₂O₄ single phase can be obtained.When the temperature rises above 400℃,Ni Co₂O₄ spinel begins to decompose to form Ni O,forming a defective spinel structure.When the temperature reaches 800℃,the CoO structure peak appears.Due to the double effect of BET and crystallinity,the mesoporous surface area（129 m2/g）and the microporous area（166 m2/g）were the most abundant at 500℃ calcination temperature.The cobalt curve area of nickel cobalt spinel is obviously higher than that of pure nickel oxide or cobalt oxide.When the calcination temperature is 500℃ and the molar ratio of nickel to cobalt is 1: 2,the obtained nickel cobalt oxide has the highest specific surface area and good pore size distribution,in the self-assembled single-chamber MEC device to get better hydrogen evolution.The last,exploring the effect of the capping crucible and the open crucible on the crystal growth behavior of the material during calcination.The BET specific surface area（118 m2/g）and the microporous specific surface area（58 m2/g）of the NiCo（C）sample in the capping crucible were higher than those in the unbonded crucible NiCo（O）Order of the mesoporous metal oxide.The optimum conditions were as follows: double solvent method,nickel-cobalt precursor molar ratio of 1: 2,500 degrees Celsius with a crucible roasting,extended to the hard template KIT-6,also obtained a better order of nickel cobalt NiCo₂O₄.The surface area reached 101 m2/g.