Zr-MOFs based BiOBr/UiO-66 nanoplates with enhanced photocatalytic activity for tetracycline degradation under visible light irradiation

Abstract

The concern about the removal of antibiotics and utilization of solar energy on environmental modification has motivated the development of photocatalysts. In this work, an organic–inorganic composite based on zirconium metal–organic frameworks and BiOBr/UiO-66 nanoplates was successfully synthesized by a facile in situ assembly. The BiOBr/UiO-66 nanocomposites presented distinctly enhanced photocatalytic degradation performance and mineralization ability toward the tetracycline (TC) under visible light irradiation. The maximum degradation activity was about 2.15 times higher than that of pristine BiOBr, and the 83.84% mineralization rate was obtained within 150 min, when the UiO-66 reached 8% in the mass ratio of raw materials, compared to theoretical BiOBr. According to the analysis of morphology characterization, phase structure, optical performance, and electrochemical measurements, the enhancement of the photo-generated electron–hole pair transfer and separation efficiency led to the improved photocatalytic performance of BiOBr/UiO-66. The reactive species were also tested through radical scavenging experiments, revealing that the main active radicals were superoxide radicals and holes during the degradation of TC. Additionally, a probable degradation route of TC has been proposed after high-performance liquid chromatography and LC/MS-MS analysis, and the photo-oxidative mechanism of TC degradation was further explored with the energy band structure measurement.

Synergistic Effects of Redox Couples and Oxygen Vacancies Improve the Tetracycline Degradation Property of La2NiMnO6

“…Because the E VB of the LNMO-based catalysts was lower than E­( • OH/H 2 O) = (2.72 eV), photogenerated h + could not oxidize H 2 O to form radicals • OH. However, the photogenerated h + on the VB could directly oxidize TC . As a consequence, the photo-excited h + also played a key role in degrading TC.…”

“…However, the photogenerated h + on the VB could directly oxidize TC. 61 As a consequence, the photo-excited h + also played a key role in degrading TC. Nevertheless,…”

“…• OH could be formed by further reducing • O 2 − according to eqs 14−16 31,61. Therefore, • OH played a weak role in degrading TC.…”

Photocatalytic Degradation of Some Typical Antibiotics: Recent Advances and Future Outlooks

“…MOFs were first discovered in the mid-1990′s by Omar Yaghi, and the invention of novel MOFs promised long-lived influence in the areas of chemistry, physics, biology, and the material sciences, particularly used extensively in photocatalysis due to their high surface area, adjustable porosity and pore volume [ 67 , 68 , 69 ]. Thus, MOFs promise to be highly-effective materials for the photocatalytic degradation of antibiotics in a solution [ 66 , 70 ]. Although various MOF-based materials have been utilized to remove antibiotics, the development of more efficient degradation agents remains a key problem facing more active MOF-based photocatalytic degradation materials with more active sites and large surface areas with group functionalization [ 66 , 67 ].…”

Visible-Light-Driven Zr-MOF/BiOBr Heterojunction for the Efficient Synchronous Removal of Hexavalent Chromium and Rhodamine B from Wastewater

“…In most of the previous studies, the Zr-MOF was mostly used as a kind of modifier in a small amount to improve the oxidative degradation performance of bismuth oxyhalide materials. 54 − 57 In our study, UiO-66-NH 2 was used as the host matrix and BiOBr was introduced to construct a heterojunction composite system. This not only retains the original excellent specific area property of the MOF but also enhances visible-light photocatalytic oxidation and reduction performance.…”