Photocatalytic degradation of tetracycline by g-C3N4 homostructure modified by cyano group and nitrogen defect

The efficiency and cleanliness of photocatalytic technology make it a promising candidate for widespread use. In recent years, the escalation of environmental pollution has accentuated its severity. Consequently, the significance of photocatalytic degradation technology has grown considerably. Graphite carbon nitride (g-C3N4) has emerged as a promising material in the field of photocatalytic degradation. However, pristine g-C3N4 still has several drawbacks, such as a poor responsiveness to visible light and a quick recombination of photogenerated carriers. Herein, a g-C3N4 homostructure photocatalyst (g-C3N4–0.5/g-C3N4–2) is reported through alkali treatment and co-sintering for the purpose of tetracycline degradation under visible light. The g-C3N4–0.5/g-C3N4–2 composites demonstrates superior degradation capability, with a degradation rate 5.664 times higher than that of pristine g-C3N4, probably due to the formation of the homostructure, which not only preserves the cyano group and nitrogen defects of g-C3N4 but also increases the material's specific surface area. Moreover, the homostructure formation enhances visible light absorption and facilitates the efficient separation of electron-hole pairs, thereby promoting overall photocatalytic performance improvement.