Abstract: Pure spinel-type nickel cobaltate (NiCo₂O₄) was sucessfully prepared by hydrothermal synthesis method under milder reaction conditions with nickel acetate and cobalt acetate as raw materials.Product was characterized by XRD,SEM,TEM,and IR.Influencing factors,such as acid-base property,mineralizers,raw material mix ratio,time,and temperature,of the reaction system were invesitgated.When the concentration of mineralizer NH₃•H₂O was more than 4 mol/L or less than 1.5 mol/L,amount-of-substance ratio of cobalt acetate to nickel acetate was higher than 7∶3 or lower than 2∶1,hydrothermal synthesis temperature was below 220 ℃ and synthesis time was less than 72 h,no pure NiCo₂O₄ will be obtained.On the other hand,under the conditions that amount-of-substance ratio of Co to Ni was 7∶3,c(NH₃•H₂O)=2.5 mol/L,hydrothermal reacting at 220 ℃ for 72 h,pure NiCo₂O₄ nano6-particles could be obtained after using acetic acid to wash a small amount of nickel oxide impurity.

Key words: hydrothermal synthesis, nickel cobaltate, spinel