A simple way to prepare nickel selenide from NiSe2 to Ni1-xSe and their formation mechanism

Abstract NiSe 2 and Ni 1-x Se (x = 0–0.15) were successfully synthesized by a simple way, including composite-salt-mediated method (CSM), composite-salt-hydroxide-mediated method (CHSM) and solvothermal method, etc. It was found that the phase structure and morphology of the products were mainly influenced by the reaction mediate, reaction time, temperature, addition of H 2 O and so on. At 210 ℃, when the reaction time is prolonged, the products can transform from NiSe 2 micro-octahedrons to Ni 1-x Se microspheres, microellipsoids, or cracked micro-octahedrons in different mediate. The chemical reaction in different mediate is studied and accordingly, the mechanism of the formation of nickel selenides is discussed in detail.