Catalyst Proximity-Induced Functionalization of h‑BN with Quat Derivatives

• Published in: Nano letters Vol. 19; no. 9; pp. 5998 - 6004
• Main Authors: Hemmi, Adrian, Cun, Huanyao, Tocci, Gabriele, Epprecht, Adrian, Stel, Bart, Lingenfelder, Magalí, de Lima, Luis Henrique, Muntwiler, Matthias, Osterwalder, Jürg, Iannuzzi, Marcella, Greber, Thomas
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 11.09.2019
• Subjects: 2D materials transfer; electrochemical process; Hexagonal boron nitride; heterogeneous catalysis on metals; 2D materials functionalization; quaternary ammonium compounds
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.9b01792

Inert single-layer boron nitride (h-BN) grown on a catalytic metal may be functionalized with quaternary ammonium compounds (quats) that are widely used as nonreactive electrolytes. We observe that the quat treatment, which facilitates the electrochemical transfer of two-dimensional materials, involves a decomposition of quat ions and leads to covalently bound quat derivatives on top of the 2D layer. Applying tetraoctylammonium and h-BN on rhodium, the reaction product is top-alkylized h-BN as identified with high-resolution X-ray photoelectron spectroscopy. The alkyl chains are homogeneously distributed across the surface, and the properties thereof are well-tunable by the choice of different quats. The functionalization further weakens the 2D material–substrate interaction and promotes easy transfer. Therefore, the functionalization scheme that is presented enables the design of 2D materials with tailored properties and with the freedom to position and orient them as required. The mechanism of this functionalization route is investigated with density functional theory calculations, and we identify the proximity of the catalytic metal substrate to alter the chemical reactivity of otherwise inert h-BN layers.