chapter  3
Boron (Carbon) Nitride Nanomaterials: Synthesis, Porosity, and Related Applications
Pages 32

Similarities between carbon and boron nitride (BN) are striking. Indeed, BN is isoelectronic to carbon. It exhibits dierent polymorphs, including a wurtzite structure (w-BN), a sphalerite (cubic) structure (c-BN), and a hexagonal structure (h-BN). e two latter forms are strongly related to the two common carbon allotropes diamond and graphite, respectively. h-BN is the

3.1 Introduction 59 3.2 Boron Nitride Nanomaterials 61

3.2.1 Nanostructures of Boron Nitride 61 Synthesis of BN Nanotubes and Nanoribbons 61 Synthesis of BN Nanosheets 62 Synthesis of Porous BN Nanosheets 62 Synthesis of BN Mesostructures 63

3.2.2 Related Applications 66 Luminescence in BN Materials 66 Water Cleaning in Porous BN Nanosheets 66

3.3 Boron Carbon Nitride Nanomaterials 72 3.3.1 Nanostructures of Boron Carbon Nitride: Syntheses and Features 72 BCN(O) Nanoparticles 72 BCN Nanotubes 73 BCN Nanosheets 73 Mesoporous BCN 75

3.3.2 Properties of BCN Nanostructures 77 Electrical Properties of BCN Nanostructures 78 Photoluminescence of BCN Nanoparticles 79 Lithium Storage in BCN Nanosheets 80 Hydrogen Storage in B(C)N Nanostructures 81

3.4 Conclusions 84 References 84

most stable phase at ambient conditions. Despite strong structural relationships between h-BN and graphite, they are not strictly speaking isomorphs because they slightly dier in the stacking between (001) layers-they exhibit strongly dierent properties. e reason of this discrepancy lies in the bonding scheme of BN: the strong polarity or partial ionicity of B-N bonds reduces the electron mean free path drastically, so that h-BN is a wide band gap semiconductor, exhibiting related UV luminescence. h-BN also possesses very good thermal conductivity, high mechanical strength, outstanding chemical inertness, thermal stability, and resistance to oxidation. Because of all these peculiar properties and its ease of fabrication, h-BN is by far the most studied polymorph of BN, and all the studied BN nanostructures are somewhat related to this structure. e development of BN nanomaterials has been strongly linked to the advent of carbon nanoscience. Indeed, BN nanotubes were discovered soon after carbon nanotubes (Chopra et  al. 1995); BN fullerenes were identied a bit more than 10 years after C60 (Golberg et al. 1998, Stephan et al. 1998), and BN nanosheets, containing one (so-called white graphene) or a few layers of h-BN, were obtained at the same time as graphene (Corso et al. 2004, Novoselov et al. 2005). Still now, the increasing research eort on BN nanostructures is most often strongly related to research on carbon nanostructures. is current way of thinking BN research has two consequences.