Facile synthesis of cadmium-doped graphite carbon nitride for photocatalytic degradation of tetracycline under visible light irradiation

In recent years, using semiconductor photocatalysts for antibiotic contaminant degradation under visible light has become a hot topic. Herein, a novel and ingenious cadmium-doped graphite phase carbon nitride (Cd-g-C3N4) photocatalyst was successfully constructed via the thermal polymerization method. Experimental and characterization results revealed that cadmium (Cd) was well doped at the g-C3N4 surface and exhibited high intercontact with g-C3N4. Additionally, the introduction of cadmium significantly improved the photocatalytic activity, and the optimum degradation efficiency of tetracycline (TC) reached 98.1%, which was exceeded 2.0 times that of g-C3N4 (43.9%). Meanwhile, the Cd-doped sample presented a higher efficiency of electrical conductivity, light absorption property, and photogenerated electron-hole pair migration compared with g-C3N4. Additionally, the quenching experiments and electron spin-resonance tests exhibited that holes (h(+)), hydroxyl radicals (center dot OH), superoxide radicals (center dot O-2(-)) were the main active species involved in TC degradation. The effects of various conditions on photocatalytic degradation, such as pH, initial TC concentrations, and catalyst dosage, were also researched. Finally, the degradation mechanism was elaborated in detail. This work gives a reasonable point to synthesizing high-efficiency and economic metal-doped photocatalysts.

Automated summary

In recent years, the use of semiconductor photocatalysts for the degradation of antibiotic contaminants under visible light has gained significant attention. This study successfully synthesized a novel cadmium-doped graphite phase carbon nitride photocatalyst and found that the introduction of cadmium significantly improved the photocatalytic activity. Additionally, the effects of various conditions on the photocatalytic degradation were investigated, and the degradation mechanism was elucidated in detail.