Significant enhancement of surface area and structural distortion of carbon nitride by recrystallization method

Solar photo-catalysis is very essential for both harvesting high-density solar energy, and environmental sustainability. A high surface area carbon nitride (HSACN), a photo-catalyst is synthesized by simple re-crystallization and calcination methods. The decrease in the size of urea crystals is ascribed to the use of different solvents and direct calcination that resulted in the formation of carbon nitride. The re-crystallization suggests that the defect-rich carbon nitride created nitrogen vacancies, which accelerated the photocatalytic activity of dyes’ degradation. The synthesized materials were characterized by X-ray powder diffraction, Field emission scanning electron microscopy, and transmission electron microscopy for structural and morphology evaluation. The corresponding high surface area carbon nitride demonstrated higher photocatalytic-dye-degradation efficiency under UV light irradiation, and higher adsorption capacity compared to graphitic carbon nitride, which is obtained without re-crystallization protocol. An increase in the surface area of HSACN has been observed due to structural disturbance caused by the growth of tiny urea crystals in carbon nitride. The nitrogen vacancies incorporation improved the absorption of extended visible light. The enhancement in photocatalytic activities are corresponding to the improved charge carrier photoexcitation, separation, and generated abundant reaction sites.