Effect of ammonium chloride on the morphology of hexagonal boron nitride prepared by magnesium thermal reduction

Hexagonal boron nitride (h-BN) crystals with cylindrical and nanoplate shape were prepared by the magnesium thermal reduction method. A simple and novel strategy successfully controlled the preferred growth direction of h-BN crystal by adding a small amount of ammonium chloride to the reaction system, realized the transformation of the h-BN crystal growth mode from cylindrical to nanoplate, and the thickness of h-BN crystal nanoplates rapidly decreased from 2 mu m to 40 nm. XRD results showed that the ammonium chloride content also significantly promoted the crystallinity of the synthesized h-BN nanoplates, and the G.I. index decreased from 2.4 to 1.9. Raman and TEM results showed that the crystallinity of synthesized h-BN was close to the properties of the single crystal.