Heterojunctions Based on BiOBr Nanosheets Decorated on α-Bi2O3 for Photodegradation of Rhodamine B

作者：Cheng, Xia; Xiao, Xinyan^*; Wang, Fei; Lu, Ting; Zhang, Yu

来源：ACS Applied Nano Materials, 2024, 7(4): 4413-4422.

DOI：10.1021/acsanm.3c05957

• CAU-17-derived coral-like alpha-Bi2O3
• BiOBr nanosheets
• alpha-Bi2O3/BiOBr nanocomposites
• type II heterojunction
• photodegradation

Photocatalysis is extensively implemented in organic pollutant degradation, and the critical point is to develop outstanding and stable photocatalysts. Herein, the synthesis of coral reef-like alpha-Bi2O3/BiOBr heterostructure photocatalysts involves the in situ growth of BiOBr nanosheets onto alpha-Bi2O3, with the latter derived through calcination utilizing a bismuth-based metal-organic framework (CAU-17) as the precursor. Under simulated sunlight, the 20% alpha-Bi2O3/BiOBr heterojunction degraded nearly 97.7% of RhB in 60 min, while pure alpha-Bi2O3 and BiOBr nanosheets degraded only 7.8 and 65.3%, respectively. Furthermore, the 20% alpha-Bi2O3/BiOBr nanocomposite exhibited superior recycling stability, degrading 86.6% RhB after four cyclic experiments. This is attributed to the fact that the nanoscale alpha-Bi2O3 material obtained by calcination can retain the exoteric diffusion channels of CAU-17, making alpha-Bi2O3/BiOBr heterojunctions have an enormous specific surface area, providing more adsorption sites and promoting their photocatalytic capacity. Free radical capture tests and electron paramagnetic resonance measurements indicated that h(+) and O-center dot(2)- were the primary active substances during photodegradation. On the basis of that, a feasible photodegradation mechanism of type II alpha-Bi2O3/BiOBr heterojunctions was proposed. This study opens up the possibility of designing type II heterojunctions with MOFs as precursors for dye degradation.