Synthesis and characterization of nanoparticles, nanotubes, nanopans, and graphene-like structures of boron nitride

By heating H<SUB>3</SUB>BO<SUB>3</SUB> with urea in 1:6 molar ratio, nanoparticles and nanotubes of BN are obtained. The urea-boric acid reaction can also be exploited to obtain graphene analogues of BN, with the number of layers depending on the relative proportions of the two reactants. Synthesis with a high proportion of urea yields a product containing graphene analogues of BN with an average of 2 layers. The surface area of BN increases with the decreasing number of layers, and the high-surface-area BN also exhibits high CO<SUB>2</SUB> adsorption. Few-layer BN can be solubilized by interaction with Lewis bases. Nanopans and nanosheets formed by graphene-like BN are generated by the vapor phase reaction of NH<SUB>3</SUB> and BBr<SUB>3</SUB> at 1223 K. Nanopans of BN, being reported for the first time, have a bottom comprising single-layer BN and a wall of 0.7 nm height. The average inner volume of the nanopan is around 400 nm<SUP>3