Synthesis of Oxygen-Deficient Bi2WO6 Photocatalysts and Their Efficient Degradation of Tetracycline

The oxygen-deficient Bi2WO6 was synthesized by a solvothermal method using ethylene glycol and ethanol as solvents. The physical and chemical properties of the as-synthesized Bi2WO6 were characterized using SEM, FT-IR, XPS and ESR. Also, its degradation performance on tetracycline and the photocatalytic mechanism were investigated. The results showed that the oxygen-deficient Bi2WO6 has regular microsphere images with narrower and more uniform pore size distribution than Bi2WO6. Moreover, under the condition of visible light irradiation for 180 min, its performance on the degradation rate of tetracycline could attain 79.68%, which is 18 percentage points higher compared to that of Bi2WO6. Furthermore, after four cycles usage, the degradation rate of tetracycline could still reach 68.64%. A mechanism for the superior performance of the as-synthesized, oxygen-deficient Bi2WO6 photocatalyst over Bi2WO6 is attributed to the oxygen vacancies which enhanced the absorption and utilization of visible light, reduced the band gap and valence band width of the catalyst, lowered the electrochemical impedance of the catalyst, as well as improved the separation and transfer efficiency of photogenerated carriers.