"Caffeine Doping" of Carbon/Nitrogen-Based Organic Catalysts: Caffeine as a Supramolecular Edge Modifier for the Synthesis of Photoactive Carbon Nitride Tubes

An alternative method for the structure tuning of carbon nitride materials by using a supramolecular approach in combination with caffeine as lining‐agent is described. The self‐assembly of the precursor complex consisting of melamine and cyanuric acid can be controlled by this doping molecule in terms of morphology, electronic, and photophysical properties. Caffeine is proposed to insert as an edge‐molecule eventually leading to hollow tube‐like carbon nitride structures with improved efficiency of charge formation. Compared to the bulk carbon nitride, the caffeine‐doped analogue possesses a higher photocatalytic activity for the degradation of rhodamine B dye. Furthermore, this approach is also shown to be suitable for the modification of carbon nitride electrodes. On the edge: A new strategy to tune the morphology, electronic structure, and photophysical properties of carbon nitride based materials by using caffeine as a “lining agent” for the supramolecular precursor complex is investigated. The resulting caffeine‐doped C3N4 structures form hollow tubes and show different electronic properties. The insertion of caffeine on the edge of the molecule creates new surface states with enhanced absorption.