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

Abstract 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 μm 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.