A facile method of activating graphitic carbon nitride for enhanced photocatalytic activity

Abstract

Activated graphitic carbon nitride (g-C₃N₄) with enhanced photocatalytic capability under visible light irradiation was fabricated by using a facile chemical activation treatment method. In the chemical activation, a mixed solution of hydrogen peroxide and ammonia was employed. The yield can reach as high as 90% after the activation process. The activation process did not change the crystal structure, functional group, morphology and specific surface area of pristine g-C₃N₄, but it introduced H and O elements into the CN framework of g-C₃N₄, resulting in a broader optical absorption range, higher light absorption capability and more efficient separation of photogenerated electrons and holes. The photoactivity was investigated by the degradation of rhodamine B (RhB) under visible light irradiation. As compared to the pristine g-C₃N₄, the activated g-C₃N₄ exhibited a distinct and efficient two-step degradation process. It was found that the RhB dye in the activated g-C₃N₄ was mainly oxidized by the photogenerated holes. It is believed that sufficient holes account for the two-step degradation process because they would significantly improve the efficiency of the N-de-ethylation reaction of RhB.