Nanoporous photocatalysts developed through heat-driven stacking of graphitic carbon nitride nanosheets

Abstract

Nanoporous graphitic carbon nitride was prepared through direct heat treatment of guanidinium cyanurate at 550–600 °C in an air atmosphere. The BET surface area of the resulting materials can reach 200 m² g⁻¹. High porosity was developed through a heat-driven stacking of g-C₃N₄ nanosheets. The mechanism was revealed in detail through TEM and N₂ adsorption measurements. Large-size g-C₃N₄ nanosheets are formed at 550 °C and stacked in a state similar to randomly creased paper slips. Further increase of treatment temperature to 600 °C results in curling and fragmentation of g-C₃N₄ nanosheets, which build up a highly porous matrix. Nanoporous graphitic carbon nitride with higher surface area exhibits better optical properties and has enhanced photocatalytic activity. The nanoporous g-C₃N₄ shows high photocatalytic activity for the decomposition of rhodamine (RhB) in an aqueous solution.