Hollow Spherical G-C3n4 Rich in Cyano Groups for Efficient Adsorption and Photodegradation of Methylene Blu

Abstract

Graphitic carbon nitride (g-C3N4) hollow microspheres are prepared by thermal condensation of melamine using CaCO3 microspheres as template. CaCO3 template not only ensures the construction of the hollow structure of g-C3N4, but also promotes the formation of a large number of cyano groups. The hollow micro-spherical structure of the g-C3N4 significantly increases its specific surface area, while the abundant cyano groups promote its ability to separate and transfer charges, thereby achieving a dual effect of morphology control and surface functionalization through a single strategy. As a model substrate, methylene blue is used to evaluate the photocatalytic performance of the g-C3N4. It reveals that these g-C3N4 hollow microspheres have both high adsorption and high degradation capabilities for methylene blue. Even for a methylene blue solution with concentration as high as 160 mg/L, which is ~ 8 times of those used in most literature, the g-C3N4 exhibits a photodegradation efficiency of ~ 94.3% in 1 h. Compared with the traditional method for preparing g-C3N4 hollow microspheres using SiO2 microspheres as template, the method reported in this work is simpler and more environmentally friendly, which is expected to lay the foundation for the large-scale application of such materials in the future.

Keywords: C3N4, carbon nitride, Photocatalysis, hollow spheres, cyano, photodegradation