Hexagonal boron nitride (h-BN) is a material with a structure analogous to graphite. It can be used in the form of nanoparticles, nanotubes, nanosheets (analogous to graphene), or 3D nanoporous materials, e.g., in sensors or as a catalyst. Hexagonal boron nitride can, for example, catalyze the oxidative dehydrogenation of propane to give propylene and ethylene. However, with existing h-BN catalysts, the olefin selectivity at high conversion rates is still too low for practical applications.

Pengcheng Dai, Xuebo Zhao, China University of Petroleum (East China), Qingdao, Yusuke Yamauchi, The University of Queensland, Brisbane, Australia, and Kyung Hee University, Yongin-si, Republic of Korea, and colleagues have prepared spherical structures consisting of boron nitride nanosheets, which can be used as catalysts for the selective oxidative dehydrogenation of propane. The team started from the metal–organic framework (MOF) ZIF-8, which consists of zinc and 2-methylimidazole, and used it as a template for their spherical structures. ZIF-8 nanoparticles were reacted with boric acid in a solvothermal process at 150 °C to give spheres made up of nanosheets of the new, boron-containing MOF Zn₂(BO₃)(C₄N₂H₅).

This new MOF was then converted to h-BN nanosheets by nitrogenization under an ammonia atmosphere at 1000 °C. The spherical structure composed of nanosheets was retained during this transformation. The resulting h-BN-nanosheet spheres can be used as a catalyst for the oxidative dehydrogenation of propane without any further activation. The system achieved an excellent olefin yield of 40.2 %, the highest value for any h-BN-based catalyst in this reaction.

• Spherical Superstructure of Boron Nitride Nanosheets Derived from Boron-Containing Metal–Organic Frameworks,
  Lei Cao, Pengcheng Dai, Jing Tang, Dong Li, Ruihua Chen, Dandan Liu, Xin Gu, Liangjun Li, Yoshio Bando, Yong Sik Ok, Xuebo Zhao, Yusuke Yamauchi,
  J. Am. Chem. Soc. 2020.
  https://doi.org/10.1021/jacs.0c01023