The Experts below are selected from a list of 117 Experts worldwide ranked by ideXlab platform

Hui Wang - One of the best experts on this subject based on the ideXlab platform.

  • Preparation of pure nickel, cobalt, nickel–cobalt and nickel–copper Alloys by hydrothermal reduction
    Journal of Materials Chemistry, 1999
    Co-Authors: Yi Li, H W Liao, Lisheng Li, Hui Wang
    Abstract:

    Reduction of aqueous NiSO 4 , CoSO 4 and CuSO 4 with hydrazine has been investigated systematically to obtain ultrafine powders of pure nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys. The results show that the pH value and the temperature are the key factors to influence the reactions. When pH ≥ 10.0 and the temperature is higher than 85°C, pure nickel particles are obtained. Pure cobalt, and nickel–cobalt and nickel–copper alloy powders can be formed only when pH ≥ 13 and the temperature is above 120°C. The mechanism for the formation of powders of nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys is discussed. The XRD patterns reveal that the as-synthesized pure cobalt is the hexagonal phase (h.c.p.), the pure nickel is the cubic phase (f.c.c.) and the Co 1–x Ni x and Cu 1–x Ni x Alloys are the f.c.c. phase only when the ratio of Ni to Co is above 1∶1 and Ni∶Cu is below 1∶9, respectively.

  • preparation of pure nickel cobalt nickel cobalt and nickel copper Alloys by hydrothermal reduction
    Journal of Materials Chemistry, 1999
    Co-Authors: Yifan Li, Linpeng Li, H W Liao, Hui Wang
    Abstract:

    Reduction of aqueous NiSO 4 , CoSO 4 and CuSO 4 with hydrazine has been investigated systematically to obtain ultrafine powders of pure nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys. The results show that the pH value and the temperature are the key factors to influence the reactions. When pH ≥ 10.0 and the temperature is higher than 85°C, pure nickel particles are obtained. Pure cobalt, and nickel–cobalt and nickel–copper alloy powders can be formed only when pH ≥ 13 and the temperature is above 120°C. The mechanism for the formation of powders of nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys is discussed. The XRD patterns reveal that the as-synthesized pure cobalt is the hexagonal phase (h.c.p.), the pure nickel is the cubic phase (f.c.c.) and the Co 1–x Ni x and Cu 1–x Ni x Alloys are the f.c.c. phase only when the ratio of Ni to Co is above 1∶1 and Ni∶Cu is below 1∶9, respectively.

Yifan Li - One of the best experts on this subject based on the ideXlab platform.

  • preparation of pure nickel cobalt nickel cobalt and nickel copper Alloys by hydrothermal reduction
    Journal of Materials Chemistry, 1999
    Co-Authors: Yifan Li, Linpeng Li, H W Liao, Hui Wang
    Abstract:

    Reduction of aqueous NiSO 4 , CoSO 4 and CuSO 4 with hydrazine has been investigated systematically to obtain ultrafine powders of pure nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys. The results show that the pH value and the temperature are the key factors to influence the reactions. When pH ≥ 10.0 and the temperature is higher than 85°C, pure nickel particles are obtained. Pure cobalt, and nickel–cobalt and nickel–copper alloy powders can be formed only when pH ≥ 13 and the temperature is above 120°C. The mechanism for the formation of powders of nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys is discussed. The XRD patterns reveal that the as-synthesized pure cobalt is the hexagonal phase (h.c.p.), the pure nickel is the cubic phase (f.c.c.) and the Co 1–x Ni x and Cu 1–x Ni x Alloys are the f.c.c. phase only when the ratio of Ni to Co is above 1∶1 and Ni∶Cu is below 1∶9, respectively.

H W Liao - One of the best experts on this subject based on the ideXlab platform.

  • Preparation of pure nickel, cobalt, nickel–cobalt and nickel–copper Alloys by hydrothermal reduction
    Journal of Materials Chemistry, 1999
    Co-Authors: Yi Li, H W Liao, Lisheng Li, Hui Wang
    Abstract:

    Reduction of aqueous NiSO 4 , CoSO 4 and CuSO 4 with hydrazine has been investigated systematically to obtain ultrafine powders of pure nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys. The results show that the pH value and the temperature are the key factors to influence the reactions. When pH ≥ 10.0 and the temperature is higher than 85°C, pure nickel particles are obtained. Pure cobalt, and nickel–cobalt and nickel–copper alloy powders can be formed only when pH ≥ 13 and the temperature is above 120°C. The mechanism for the formation of powders of nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys is discussed. The XRD patterns reveal that the as-synthesized pure cobalt is the hexagonal phase (h.c.p.), the pure nickel is the cubic phase (f.c.c.) and the Co 1–x Ni x and Cu 1–x Ni x Alloys are the f.c.c. phase only when the ratio of Ni to Co is above 1∶1 and Ni∶Cu is below 1∶9, respectively.

  • preparation of pure nickel cobalt nickel cobalt and nickel copper Alloys by hydrothermal reduction
    Journal of Materials Chemistry, 1999
    Co-Authors: Yifan Li, Linpeng Li, H W Liao, Hui Wang
    Abstract:

    Reduction of aqueous NiSO 4 , CoSO 4 and CuSO 4 with hydrazine has been investigated systematically to obtain ultrafine powders of pure nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys. The results show that the pH value and the temperature are the key factors to influence the reactions. When pH ≥ 10.0 and the temperature is higher than 85°C, pure nickel particles are obtained. Pure cobalt, and nickel–cobalt and nickel–copper alloy powders can be formed only when pH ≥ 13 and the temperature is above 120°C. The mechanism for the formation of powders of nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys is discussed. The XRD patterns reveal that the as-synthesized pure cobalt is the hexagonal phase (h.c.p.), the pure nickel is the cubic phase (f.c.c.) and the Co 1–x Ni x and Cu 1–x Ni x Alloys are the f.c.c. phase only when the ratio of Ni to Co is above 1∶1 and Ni∶Cu is below 1∶9, respectively.

Linpeng Li - One of the best experts on this subject based on the ideXlab platform.

  • preparation of pure nickel cobalt nickel cobalt and nickel copper Alloys by hydrothermal reduction
    Journal of Materials Chemistry, 1999
    Co-Authors: Yifan Li, Linpeng Li, H W Liao, Hui Wang
    Abstract:

    Reduction of aqueous NiSO 4 , CoSO 4 and CuSO 4 with hydrazine has been investigated systematically to obtain ultrafine powders of pure nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys. The results show that the pH value and the temperature are the key factors to influence the reactions. When pH ≥ 10.0 and the temperature is higher than 85°C, pure nickel particles are obtained. Pure cobalt, and nickel–cobalt and nickel–copper alloy powders can be formed only when pH ≥ 13 and the temperature is above 120°C. The mechanism for the formation of powders of nickel and cobalt, and of nickel–cobalt and nickel–copper Alloys is discussed. The XRD patterns reveal that the as-synthesized pure cobalt is the hexagonal phase (h.c.p.), the pure nickel is the cubic phase (f.c.c.) and the Co 1–x Ni x and Cu 1–x Ni x Alloys are the f.c.c. phase only when the ratio of Ni to Co is above 1∶1 and Ni∶Cu is below 1∶9, respectively.

E. Ndzebet - One of the best experts on this subject based on the ideXlab platform.

  • Hydrogen evolution reaction (h.e.r.) in an acidic or basic medium on nickel electrodeposited with PW_12O _40 ^3- and Cu^2+
    Journal of Applied Electrochemistry, 1993
    Co-Authors: O. Savadogo, E. Ndzebet
    Abstract:

    The hydrogen evolution reaction (h.e.r.) on electrodeposited nickel from a chemical bath containing Cu^2-, with and without PW_12O _40 ^3- , was investigated. Hydrogen cathodes based on Nickel-Copper Alloys and PW_12O _40 ^su3- reduced species are better electrocatalysts in 1 M H_2SO_4 or 3 m KOH at 298 K than Nickel-Copper Alloys deposited without PW_12O _40 ^3- . The electrocatalytic performance of the former cathodes was attributed to their chemical composition. This electrocatalytic activity for the h.e.r. was examined as a function of the [Cu^2+] or [PW_12O _40 ^3- ] in the electrodeposition bath. The influence of nickel salt anions on the h.e.r. electrocatalytic activity of the electrodes was also investigated. The chemical surface composition of the electrodes was analysed by X-ray photoelectron spectroscopy (XPS). It was shown that the electrocatalytic parameters were correlated to the quantity of tungsten in the electrode surface. The various factors causing the improvement in the electrocatalytic activity are discussed.

  • Hydrogen evolution reaction (h.e.r.) in an acidic or basic medium on nickel electrodeposited with PW12O 40 3- and Cu2+
    Journal of Applied Electrochemistry, 1993
    Co-Authors: O. Savadogo, E. Ndzebet
    Abstract:

    The hydrogen evolution reaction (h.e.r.) on electrodeposited nickel from a chemical bath containing Cu2-, with and without PW12O 40 3- , was investigated. Hydrogen cathodes based on Nickel-Copper Alloys and PW12O 40 su3- reduced species are better electrocatalysts in 1 M H2SO4 or 3m KOH at 298 K than Nickel-Copper Alloys deposited without PW12O 40 3- . The electrocatalytic performance of the former cathodes was attributed to their chemical composition. This electrocatalytic activity for the h.e.r. was examined as a function of the [Cu2+] or [PW12O 40 3- ] in the electrodeposition bath. The influence of nickel salt anions on the h.e.r. electrocatalytic activity of the electrodes was also investigated. The chemical surface composition of the electrodes was analysed by X-ray photoelectron spectroscopy (XPS). It was shown that the electrocatalytic parameters were correlated to the quantity of tungsten in the electrode surface. The various factors causing the improvement in the electrocatalytic activity are discussed.