Bottom-up synthesis of highly soluble carbon materials

Abstract

Oxygen-containing carbon materials such as graphene oxide have been studied intensively for a decade because of the high oxygen content, which is beneficial to disperse carbon materials in solutions and to support either metals or metal oxides on carbon materials. However, various oxygen-containing functional groups exist on carbon materials and controlling the structures is almost impossible. In this work, phloroglucinol (PG), which has a symmetrical structure with three hydroxyl groups relative to six aromatic carbon atoms, was found to be the best precursor among PG, cyanuric acid, trimesic acid, and melamine because of the high yield (63 wt%) at 573 K even in an open system which is essential for mass production. The materials synthesized from PG also showed the high dispersibility and/or solubility in solvents (N-methyl-2-pyrrolidone and N,N-dimethylformamide) and the low temperature to form carbon materials (573 K), which can be explained from (002) and (10) in X-ray diffraction pattern. X-ray photoelectron spectroscopy, Fourier transform infrared spectrometer, carbon-13 nuclear magnetic resonance with the aid of calculation of both spectra and carbonization mechanisms revealed that the high solubility of carbonized PG originates from the presence of ether and cyclic ether, which were formed from dehydration of hydroxy groups, and also some remained hydroxyl groups in carbonized PG. Oxygen-containing groups in carbonized PG were effective as an antioxidant. In addition, the coating of carbonized PG on silica nanoparticles imparted conductivity and lubricity to silica nanoparticles.