| Transition metal nanoparticles have excellent physical and chemical properties which have huge potential applications in energy,catalysis,environmental,biomedical.However,the transition metal nanoparticles tend to aggregate and oxidize.Carbon nanomaterials have good electron transport capability and chemical stability,which can be used as carrier to improve the dispersibility and stability of transition metal nanoparticles.Therefore,the preparation of high stable and highly active transition metal carbon nanocomposites have became a hot topic.This thesis designed and synthesized a new type of organic molecules intercalated layered hydroxide as a single precursor.Through a simple solid-state pyrolysis,one-dimensional nickel/carbon-based nanocomposite material with uniform morphology,high dispersion,high degree crystallinity was synthesized.The performance of nanocomposites in the field of hydrogen production by electrolysis water have been studied in detail.The specific research contents are as follows:1.Layered nickel hydroxide intercalated with salicylic acid ions have been sythesized by using cheap water nickel nitrate and sodium salicylate as raw material.In the absence of reductant and template agent,the one dimensional Ni@C nanocomposites were prepared.The effect of precursors composition and solid state on the composition and crystal structure were studied.And the features were studied by using SEM,HRTEM,XRD,Raman,FT-IR,XPS,TG and BET.Results showed that the one dimensional Ni@C nanorods had uniform morphology(about 50 nm in diameter,2 um in length)and nano-particle(less than 10 nm),high dispersion,high crystallinity,large specific surface area(193.5 m2/g),abundant functional groups and strong interface interaction(Ni-O-C),and other structural features.Research on the electrocatalytic properties of one dimensional Ni@C nanocomposites which were prepared under different pyrolytic temperature.The experimental results showed that one dimensional Ni@C nanocomposites(900 ?)had the highest catalytic activity and excellent stability in which overpotential could be as low as 78 mV(i = 10 mA/cm2).2.Introducing metal zinc on layer board,layered zinc/nickel hydroxide precursors were compounded.A new one-dimensional nickel-base multielement carbon nanocomposites were successfully prepared through solid-state pyrolysis.Study the effect of pyrolysis temperature on the structure,one-dimensional Ni3ZnCo.7/Ni@C nanocomposites were sythesized controllably at the temperature of 700?-800?.HRTEM and XRD show that small size,high dispersion,high crystallinity Ni3ZnC0.7 nanoparticles(about 7 nm)and Ni nanoparticles(about 8 nm)were setted in highly graphitized carbon nanorods(about 40 nm in diameter).XPS and FT-IR showed that there was a large number of hydroxyl groups on the carbon surface,which made it hydrophilic.There was a strong valence bond between Ni3ZnC0.7 Ni and C which guaranteed chemical stability.In addition,Ni3ZnC0.7 was continuously reduced to a metal Ni and Zn phase as solid temperature increased,in which the metal Zn acted as a template to form porous structure.ZnO phase was appeared as lower solid temperature.In 500-600 ?,one dimensional Ni3ZnC0.7/ZnO@C nanocomposites were prepared successfully.In electric catalytic performance testing,a one-dimensional Ni3ZnC0.7/Ni@C nanocomposites showed excellent performance,in which overpotential(i=10 mA/cm2,32 mV)and tafel slope(37 mV/dec)was lower than commercial Pt/C(35 mV,80 mV/dec),and had excellent stability(performance to keep more than 98%during 10 h test).At the same time,the photocatalytic performance of the material was investigated by using visible light as a probe,and the results showed that it had excellent photocatalytic activity.In conclusion,we have developed a high quality different system of one-dimensional nickel-based carbon nanocomposite material which have excellent catalytic properties.And the preparation method is simple?green?economy.Sugegest potential industrial application value in energy and environment. |
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