Selective doping of nitrogen into carbon materials without catalysts

Selective doping of nitrogen into carbon materials in the absence of catalysts is a key for various applications of carbon materials. It is well known that most nitrogen-containing raw materials generate unnecessary functional groups during carbonization. Many researchers have noticed the significance of the selective nitrogen doping, whereas only a few works have reported the selective doping. In addition, those few works used catalysts to synthesize nitrogen-doped carbon materials, but the presence of catalysts limits the applications of nitrogen-doped carbon materials. This study found an unusual aromatic compound, imidazo[1,2-a]pyridine (IP), which maintained 88 % of the functional groups of as-received IP even after carbonization at 673 K in the absence of catalysts, and the functional groups were further maintained up to 773 K. The percentage of remaining functional groups was revealed using our state-of-the-art techniques of simulated X-ray photoelectron spectroscopy and Raman spectroscopy combined with transition state calculation using density functional theory. The low carbonization temperature as well as selective doping of nitrogen was achieved because of the low activation energy of dehydrogenation reaction among IP molecules compared to the high activation energy of radical formation for scission of C–N bonding.