Preparation Of Nanometer Nickel-based Materials And Their Electrocatalytic Oxidation Of Urea

Urea（CO（NH₂）₂）is the fertilizer product with the highest nitrogen content currently used in the market.At the same time,there is also a large amount of urea in the waste water produced by human production and living.In the natural environment,it will produce certain pollution.Urea oxidation reaction（UOR）is an effective reaction to decompose urea,which can effectively solve the environmental problems caused by urea emission,At the same time,UOR is a good hydrogen production reaction,which requires lower theoretical voltage than the traditional hydrolytic hydrogen production,and is expected to become a widely used industrial hydrogen production method in the future,However,UOR is a 6e^-reaction process,which produces more gas,resulting in a slow reaction process.Therefore,the research focus in this direction is to find efficient catalyst materials to improve the reaction rate.The content of this work starts from the idea of nickel-based materials.In the second chapter,it mainly introduces the materials with lamellate structure of Fe doped nickel metal organic framework,and obtains the best performance materials by adjusting different proportions,SEM,TEM,XRD,XPS,FTIR,Raman and other methods were used to analyze the microstructure of the materials,A series of UOR tests were also carried out,and the results showed that Fe₁-Ni₅-MOF doped material had the best performance,which was a uniformly distributed 2μm sheet material,At1.328V（vs.RHE）,the current density is 10 m A·cm^-2,the Tafel slope is 16.2mV·dec^-1,and the i-t curve shows that the current density is still stable at 40h.In the third chapter,the bifunctional characteristics of Fe-Ni₃S₂（Fe-Ni₃S₂）doped with LDH synthesized from nickel foam and then modified by sulfurization were introduced.At the same time,the morphology and microstructure characteristics of the material were analyzed by SEM,TEM,XRD,XPS and Raman tests.According to UOR and HER performance tests,the current density at 1.30V（vs.RHE）is 10m A·cm^-2,and the Tafel slope is 25.8m V·dec^-1.The i-t curve shows that the current density maintains a good stability within 10h.In HER reaction,it can reach 10m A·cm^-2at 31.4 m V,and the Tafel slope is 82 m V·dec^-1,indicating that this material has good bifunctional properties.