Reversible Intercalation of Hexagonal Boron Nitride\nwith Brønsted Acids

Abstract

Hexagonal\nboron nitride (h-BN) is an insulating compound that is\nstructurally similar to graphite. Like graphene, single sheets of\nBN are atomically flat, and they are of current interest in few-layer\nhybrid devices, such as transistors and capacitors, that contain insulating\ncomponents. While graphite and other layered compounds can be intercalated\nby redox reactions and then converted chemically to suspensions of\nsingle sheets, insulating BN is not susceptible to oxidative intercalation\nexcept by extremely strong oxidizing agents. We report that stage-1\nintercalation compounds can be formed by simple thermal drying of\nh-BN in Brønsted acids H₂SO₄, H₃PO₄, and HClO₄. X-ray photoelectron and vibrational\nspectra, as well as electronic structure and molecular dynamics calculations,\ndemonstrate that noncovalent interactions of these oxyacids with the\nbasic N atoms of the sheets drive the intercalation process.