Molten salt synthesis of tetragonal carbon nitride hollow tubes and their application for removal of pollutants from wastewater

Carbon nitride has attracted extensive attention because of its promising properties and great application potential in photocatalysis, electrocatalysis, bioimaging and biomedicine. In this work, carbon nitride with a novel morphology, i.e., tetragonal carbon nitride hollow tube (TCNT), was in-situ synthesized by a molten salt method at 450 °C using melamine as the starting precursor. As-prepared TCNTs were 2–20 μm long and 50–2000 nm wide and possessed higher content of impurity nitrogen and larger specific surface area than conventional bulk g-C₃N₄ (B-CN). A possible salt-assisted self-assembly mechanism is believed to have dominated the formation of TCNTs. As-prepared TCNTs exhibited superior photocatalytic activities and adsorption performance for methylene blue and phenol degradation to B-CN, suggesting that they could be potentially used as a promising photocatalyst and adsorbent.