| In this project, we prepared several different morphologies by microwavehydrothermal process using Ni(NO3)2·6H2O, CO(NH2)2as raw materials anddeionized water, ethanol and tetrahydrofuran as solvent. The NiO with similarstructrue was obtained after thermal decomposition of the precursor. Theas-obtained products were well characterized by X-ray diffraction,thermogravimetry, scanning electronic microscopy, energy dispersivespectrometer, transmission electron microscopy, selected area electronic diagram,fourier transform infrared spectroscopy and ultraviolet-visible. Theelectrochemical character was carried out by cyclic voltammetry and ACimpedance.(1) α-Ni(OH)2percursor with microballoon sphere was synthesized usingPVP as surfactant, nickel nitrate and urea as raw materials through amicrowave-assisted hydrothermal method. The NiO with similar structrue wasobtained after thermal decomposition of the precursor at500°C.The as-obtainedproducts were well characterized by XRD, SEM, TEM, FTIR and theelectrochemical performance was initially researched. The experimental resultsshow that the NiO was cubic system and the morphology was microballoonsphere. The CVs shows that the electrode of NiO had obvious faraday quasicapacitance and stabilized electrochemical character.(2) A novel hierarchical precursor microsphere architectures weresuccessfully fabricated via microwave hydrothermal process in the presence ofan anion surfactant Poly(N-vinyl-2-pyrrolidone), nickel nitrate and urea as rawmaterials. These NiO microspheres with similar morphology were also obtainedby a simple thermal decomposition of the as-synthesized precursor at500°C for2h in air. The experimental results show that that the pure phase NiO has beenformed. These NiO microspheres are also composed of stacked nanoparticles.The specific capacitance of NiO is about208.4F/g and the good electrochemical performance of NiO could be due to the increased defects and interspace fromthe stacking vacancies of the NiO microsphere. Finally, a Simple formationmechanism is also discussed by a scheme.(3) Hexagonal precursor nanosheets were successfully synthesized via amicrowave-assisted hydrothermal process in the presence of an anion surfactantPoly(N-vinyl-2-pyrrolidone)(PVP, K30) using a two-phase system, nickel nitrateand urea as raw materials. NiO with a similar morphology was also obtained by asimple thermal decomposition of the as-synthesized precursor at400°C for2hin air. The experimental result indicates that pure phase oxidation nickel havebeen formed. NiO are also hexagonal nanosheets with an aspect ratio of about1.The TEM results reveal the internal structural information of the NiO suggestingthat NiO consisted of primary nanocrystals.(4) A novel precursor nanoflowers were successfully fabricated viamicrowave hydrothermal process in the presence of an anion surfactantPoly(N-vinyl-2-pyrrolidone), nickel nitrate and urea as raw materials. NiO withsimilar morphology was also obtained by a simple thermal decomposition of theas-synthesized precursor at400°C for2h in air. The experimental resultindicates pure phase NiO has been formed and these nanoflowers were made ofmany2D nanosheets, which are decussate. Diameter distributions of NiOdisplays the size of the particles were mainly distributed in the rang of500nm-1μm. Contrast experiments demonstrated that both the surfactant and the mixedsolvent play very critical roles in controlling the final morphology of ourproducts.(5) The precursor architectures similar with peony were successfullyfabricated via microwave hydrothermal process in the presence of an surfactantSodium carboxy methyl cellulose, nickel nitrate and urea as raw materials. NiOwith a similar morphology was also obtained by thermal decomposition of theprecursor at400°C for2h in air. The experimental results show that the peonyswere made of many2D sheets. Electrochemical performance test shows that theelectrode of NiO had obvious faraday quasi capacitance and stabilizedelectrochemical character. |
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