On the morphology evolution of the h-BN prepared via a combustion synthesis route with addition of Ni(NO3)2·6H2O

The present study successfully synthesized hexagonal boron nitride (h-BN) with different morphologies, including flake, dendritic, and spherical shapes, using a one-step combustion synthesis method in a short period of time. A simple and innovative strategy was employed to control the preferred growth direction of h-BN crystals by adding a small amount of Ni(NO₃)₂·6H₂O. By adjusting the addition of Ni(NO₃)₂·6H₂O, morphology of h-BN was manipulated from flake to spherical, and the formation mechanism was investigated. Two mechanisms were proposed to explain the different morphologies of as-grown h-BN in vapor-solid (VS) and vapor-liquid-solid (VLS) processes. This study provides valuable insights into the preparation of h-BN with diverse morphologies through combustion synthesis methods, which would guide future research in this field.