Revealing an Unexpected Chemical Reactivity of Boron Nitride to H <sub>2</sub> O and Alkane Molecules
Jie Fan, Wen‐Cui Li, Yifan Zhang, Weixi Chen, Zhankai Liu, Jichun Jiang, Yuenan Zheng, Lei He, Lei Hua, Dongqi Wang, An‐Hui Lu
Abstract
Herein, substantial experimental evidence reveals the unexpected chemical reactivity of inert hexagonal boron nitride ( h -BN) to H 2 O, CH 4, and C 2 H 6 under mild conditions. H 2 O molecules dissociate at B–N edge sites and insert into the B–N bond even under ambient conditions. Detailed spectroscopic characterization shows this process protonates nitrogen sites and hydroxylates boron sites, forming N–H and B–OH groups. Ultimately, the NH 4 + and B(OH) 4 – ions are released into water as the final products of nitrogen protonation and boron hydroxylation. This reactivity is significantly enhanced at the oxygen-doped B–N edges. Theoretical simulations reveal that strong orbital interactions between the H (1s) orbitals of H 2 O and the B (2p)/N (2p) orbitals of the B–N edge produce significant chemical stress at the adsorption sites, promoting the dissociation and subsequent insertion of H 2 O into the B–N bonds. Furthermore, we show that CH 4 and C 2 H 6 can be oxidized to CO and trace CH 3 OH in water over boron nitride at mild temperatures without an additional oxidant. The 18 O isotope-tracing experiment confirms that the oxygen in the boron nitride matrix is responsible for the activation and oxidation of the C–H bond of CH 4 and C 2 H 6 . Simultaneously, the released NH 4 + and B(OH) 4 – ions provide a reaction microenvironment enabling the thermodynamically spontaneous hydration of formed CO to formate. These findings fundamentally challenge the long-standing paradigm of h -BN as a chemically inert material under mild conditions.