Carbon nitrides have recently come into focus for photo- and thermal catalysis, both as support materials for metal nanoparticles as well as photocatalysts themselves. While many approaches for the synthesis of three-dimensional carbon nitride materials are available, only top-down approaches by exfoliation of powders lead to thin film flakes of this inherently two-dimensional material. Here, we describe an in situ on-surface synthesis of monolayer 2D carbon nitride films, as a first step towards precise combination with other 2D materials. Starting with a single monomer precursor, we show that 2,5,8-triazido-s-heptazine (TAH) can be evaporated intact, deposited on a single crystalline Au(111) or graphite support, and activated via azide decomposition and subsequent coupling to form a covalent polyheptazine network. We demonstrate that the activation can occur in three pathways, via electrons (X-ray illumination), photons (UV illumination) and thermally. Our work paves the way to coat materials with extended carbon nitride networks which are, as we show, stable under ambient conditions.
@article{arxiv.2305.01538,
title = {On-Surface Carbon Nitride Growth from Polymerization of 2,5,8-Triazido-s-heptazine},
author = {Matthias Krinninger and Nicolas Bock and Sebastian Kaiser and Johanna Plansky and Tobias Bruhm and Felix Haag and Francesco Allegretti and Ueli Heiz and Klaus Koehler and Barbara A. J. Lechner and Friedrich Esch},
journal= {arXiv preprint arXiv:2305.01538},
year = {2023}
}