One-pot synthesis of flower-like Bi2WO6/BiOCOOH microspheres with enhanced visible light photocatalytic activity

Herein, flower-like Bi2WO6/BiOCOOH heterojunction photocatalysts were synthesized by one-pot method. Morphological characterizations had demonstrated that the Bi2WO6 nanoparticles were tightly anchored on the surface of BiOCOOH, which indicated that the successful synthesis of the Bi2WO6-BiOCOOH photocatalysts. Compared with pure BiOCOOH and Bi2WO6, the Bi2WO6/BiOCOOH photocatalysts had exhibited a red shift in absorption edge and enhanced visible light absorption. EIS, PL and photocurrent response results suggested that the form of the Bi2WO6-BiOCOOH heterojunction facilitated the separation of photogenerated electron and hole pairs. Furthermore, the photoactivity of Bi2WO6/BiOCOOH were evaluated by the photocatalytic degradation of tetracycline (TC) and ciprofloxacin (CIP) under the simulated sunlight irradiation. The results manifested that the W/Bi-2 photocatalyst exhibited the best photocatalytic activity, which TC was degraded by 88 % within 75 min and CIP was degraded by 90 % within 90 min. The improvement of photocatalytic activity was mainly attributed to the decrease in the composite rate of photo-induced electron-hole pairs. Radical trapping experiments and EPR results indicated that holes (h(+)) and superoxide radicals (center dot O-2(-)) were dominant during the degradation of TC. The possible photocatalytic mechanism was discussed based on the band structures of BiOCOOH and Bi2WO6.