Monodisperse micro-nano nickel powders have been prepared by chemical reduction of aqueous solution NiSO_(4),NaOH and NaH_(2)PO_(2),and the influence of pH value and initial concentration of NiSO_(4) on the size,struc...Monodisperse micro-nano nickel powders have been prepared by chemical reduction of aqueous solution NiSO_(4),NaOH and NaH_(2)PO_(2),and the influence of pH value and initial concentration of NiSO_(4) on the size,structure,morphology and microwave absorption properties of nickel powders were investigated.The crystal structure of nickel powders was characterized by X-ray diffraction(XRD).And the morphology of the as-synthesized products was characterized by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The microwave absorption properties of the composite materials were characterized by network analyzer.The result indicates that the growth of nickel powders produced by NiSO_(4) and NaH_(2)PO_(2) at alkaline condition deeply relies on pH value and initial concentration of NiSO_(4) in reaction system.Different sizes of nickel powders with the diameter of 1.5μm and 180 nm were produced at the pH value of 10 and initial concentration of NiSO_(4) at 0.5 mol/L.The network analyzer showed definite microwave absorption properties of nickel powders with different sizes in the range of 0.5-18.0 GHz.展开更多
A novel coprecipitation-reduction process has been proposed for preparing highly selective Cu/ZnO/Al 2O 3 catalysts for methanol synthesis from CO 2 hydrogenation. Compared to the catalysts prepared by the conventiona...A novel coprecipitation-reduction process has been proposed for preparing highly selective Cu/ZnO/Al 2O 3 catalysts for methanol synthesis from CO 2 hydrogenation. Compared to the catalysts prepared by the conventional method, the new catalysts prepared via the new method exhibit much higher BET surface area and pore size, much smaller crystallite size and higher catalytic activity and selectivity in CO 2 hydrogenation to methanol. It is also found that the molar ratio of Cu + to Cu 0 on the surface of the catalyst obtained by coprecipitation-reduction is much higher than that on the reduced catalyst obtained by the conventional method, which could be crucial for its high activity and selectivity for catalytic hydrogenation of CO 2 to methanol.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.61331005the National Natural Science Foundation of China under Grant No.11274389+4 种基金the National Natural Science Foundation of China under Grant No.21471159the Special Funds for Author of Annual Excellent Doctoral Degree Dissertation of China under Grant No.201242the fund of the State Key Laboratory of Inorganic Synthesis and Preparative Chemistry under Grant No.2015-09the Shaanxi Provincial Natural Science Foundation of China under Grant No.2015JM2042the Shaanxi Province Scientific and Technology Innovation Team Foundation of China under Grant No.2014KCT-05.
文摘Monodisperse micro-nano nickel powders have been prepared by chemical reduction of aqueous solution NiSO_(4),NaOH and NaH_(2)PO_(2),and the influence of pH value and initial concentration of NiSO_(4) on the size,structure,morphology and microwave absorption properties of nickel powders were investigated.The crystal structure of nickel powders was characterized by X-ray diffraction(XRD).And the morphology of the as-synthesized products was characterized by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The microwave absorption properties of the composite materials were characterized by network analyzer.The result indicates that the growth of nickel powders produced by NiSO_(4) and NaH_(2)PO_(2) at alkaline condition deeply relies on pH value and initial concentration of NiSO_(4) in reaction system.Different sizes of nickel powders with the diameter of 1.5μm and 180 nm were produced at the pH value of 10 and initial concentration of NiSO_(4) at 0.5 mol/L.The network analyzer showed definite microwave absorption properties of nickel powders with different sizes in the range of 0.5-18.0 GHz.
文摘A novel coprecipitation-reduction process has been proposed for preparing highly selective Cu/ZnO/Al 2O 3 catalysts for methanol synthesis from CO 2 hydrogenation. Compared to the catalysts prepared by the conventional method, the new catalysts prepared via the new method exhibit much higher BET surface area and pore size, much smaller crystallite size and higher catalytic activity and selectivity in CO 2 hydrogenation to methanol. It is also found that the molar ratio of Cu + to Cu 0 on the surface of the catalyst obtained by coprecipitation-reduction is much higher than that on the reduced catalyst obtained by the conventional method, which could be crucial for its high activity and selectivity for catalytic hydrogenation of CO 2 to methanol.
