Visible-light photocatalytic tetracycline degradation over nanodots-assembled N-ZrO2-x nanostructures: Performance, degradation pathways and mechanistic insight

Abstract Nanodots-assembled N-ZrO2-X nanostructures were designed and prepared by facile modified solvothermal method with g-C3N4 as the nitrogen source. The prepared sample showed accumulated porous structures with nanodots and part of the sample presented oriented assembling features among nanodots. Besides, the experimental results also indicated that the N-ZrO2-X nanocrystals showed much narrower bandgap energy and visible-light absorption to compare with that of commercial ZrO2, mainly attributed to N doping and formation of oxygen vacancy species. These above findings contributed to the easy excitation of N-ZrO2-X nanocrystals by visible-light irradiation, accelerating the charge separation, and providing abundant reactive sites for efficient visible-light photodegradation of tetracycline. The photocatalytic reaction rate constant of N-ZrO2-x nanocrystals was calculated to be approximately 0.01563 min-1, which is 5.52 times of pristine g-C3N4, and far better than that of commercial ZrO2. Finally, possible visible-light photodegradation pathways and photocatalytic mechanism were also proposed.