Hydrothermal synthesis of nano nickel phosphides and investigation of their thermal stability

Nanometer scale nickel phosphide particles (Ni2P and Ni12P5) were synthesized via a mild hydrothermal method with red phosphor and nickel chloride as raw materials. X-ray diffraction, energy dispersive spectrometry, transmission electron microscopy, scanning electron microscopy and differential thermal analysis-thermogravimetric analysis were employed to characterize the resulting products. The results showed that the as-prepared products were well crystallized and particle sizes ranged from 10 to 40 nm. Investigation of raw material ratios and initial pH of the reaction system showed increasing P/Ni ratio did benefit the formation of Ni2P but went against obtaining Ni12P5 and nano-particles were obtained only in an alkaline environment. Subsequent differential thermal analysis-thermogravimetric analysis indicated that Ni2P remained as the major phase till 500 degrees C in an air atmosphere.