Fabrication of Co3O4 and Au co-modified BiOBr flower-like microspheres with high photocatalytic efficiency for sulfadiazine degradation

• Published in: Separation and purification technology Vol. 234; p. 116100
• Main Authors: Guan, Zhipeng, Li, Qiaoying, Shen, Bin, Bao, Shenyuan, Zhang, Jinlong, Tian, Baozhu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2020
• Subjects: Antibiotic; BiOBr flower-like microspheres; Photocatalytic degradation; Selective deposition; Spacial charge carrier separation; Spacial charge carrier separation; Photocatalytic degradation; Antibiotic; BiOBr flower-like microspheres; Selective deposition
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2019.116100

Au-BiOBr-Co3O4 hierarchical flower-like microspheres were constructed for the first time by the hydrothermal and photo-deposition methods. The reaction rate constant of Au-BiOBr-Co3O4 for sulfadiazine degradation was increased 17 times compared with single BiOBr. [Display omitted] •Au-BiOBr-Co3O4 flower-like microsphere was synthesized by stepwise photo-deposition methods.•Au and Co3O4 can effectively enhance both the visible-light absorption and charge carrier separation.•The degradation effeciency of sulfadiazine was increased 17 times from BiOBr to Au-BiOBr-Co3O4.•The desulfonated and bromized products are the main intermediates during SD degradation. For the first time, we fabricated Au-BiOBr-Co3O4 hierarchical flower-like microspheres by hydrothermal and photo-deposition methods. Au and Co3O4 nanoparticles (NPs) were selectively deposited on the {0 0 1} and {1 1 0} facets of BiOBr nanopetals, respectively. The light absorption, photoluminescence (PL), and electrochemical analyses revealed that the selectively deposited Au and Co3O4 can effectively enhance both the visible-light absorption and charge carrier separation in space. The photocatalytic degradation of sulfadiazine (SD) indicated that the degradation of SD follows the pseudo-first-order reaction and the reaction rate constant was increased 17 times from BiOBr flower-like microspheres (0.00014 min−1) to Au and Co3O4 co-modified Au-BiOBr-Co3O4 flower-like microspheres (0.00254 min−1). From the high performance liquid chromatography-mass spectrometry (HPLC-MS) measurement, it was disclosed that the desulfonated and bromized products are the main intermediates during SD degradation over Au-BiOBr-Co3O4. Meanwhile, the reactive species trapping experiments confirmed that Au-BiOBr-Co3O4 can produce h+, O2−, and Br0 reactive species responsible for antibiotic degradation. On the basis of these experiment results and discussion, the degradation mechanism of SD over Au-BiOBr-Co3O4 was tentatively discussed. We think this work provides a reference to fabricate novel photocatalytic materials for the effective degradation of antibiotics.