Fabrication of 0D/1D Bi2MoO6/Bi/TiO2 heterojunction with effective interfaces for boosted visible-light photocatalytic degradation of tetracycline

Construction of functionalized In-based metal organic framework/BiOCl1-xIx Z-scheme heterojunction for efficient photocatalytic degradation of tetracycline: Performance and mechanism

The environmental implications of antibiotics have drawn widespread attention. Numerous monomer-based bismuth oxide halide catalysts have been extensively studied to remove tetracycline (TC) from aquatic environments. Integrating bismuth oxide halide composites with In-based metal organic framework (NH2-MIL-68(In)) might potentially serve as a novel strategy. By meticulously adjusting Cl and I within the composite bismuth halide oxide (B-x), a suite of purpose built heterojunctions (NMB-x) were synthesized, which were engineered to facilitate the efficient photodegradation of TC in simulated and actual aquatic environments. The incorporation of Z-scheme heterojunctions yielded a significant enhancement in photocatalytic responsiveness and charge carrier separation. Notably, NMB-0.3 demonstrated remarkable TC removal efficiency of 88.52 ± 3.05%, which is 3.74 times of B-0.3 within 90 min. The apparent quantum yield was also increased from 8.97% (B-0.3) to 19.68% (NMB-0.3). The removal of TC from natural water bodies was also assessed. Moreover, the photocatalyst concentration, assessed using response surface method, was found to show influential factors on TC removal. In addition, density functional theory (DFT) simulations were employed to identify vulnerable sites within TC. Intermediates and pathways in the photodegradation of TC have also been inferred. Furthermore, a comprehensive environmental toxicity assessment of representative intermediates demonstrated that these intermediates exhibited significantly reduced environmental toxicity compared to TC. This study provides a new approach to the design strategy of efficient and environmentally friendly MOF-based photocatalysts.

Construction of Built-In Electric Field in TiO2@Ti2O3 Core-Shell Heterojunctions toward Optimized Photocatalytic Performance

A series of Ti₂O₃@TiO₂ core-shell heterojunction composite photocatalysts with different internal electric fields were synthesized using simple heat treatment methods. The synthesized Ti₂O₃@TiO₂ core-shell heterojunction composites were characterized by means of SEM, XRD, PL, UV-Vis, BET, SPV, TEM and other related analytical techniques. Tetracycline (TC) was used as the degradation target to evaluate the photocatalytic performance of the synthesized Ti₂O₃@TiO₂ core-shell heterojunction composites. The relevant test results show that the photocatalytic performance of the optimized materials has been significantly enhanced compared to Ti₂O₃, while the photocatalytic degradation rate has increased from 28% to 70.1%. After verification via several different testing and characterization techniques, the excellent catalytic performance is attributed to the efficient separation efficiency of the photogenerated charge carriers derived from the built-in electric field formed between Ti₂O₃ and TiO₂. When the recombination of electrons and holes is occupied, more charges are generated to reach the surface of the photocatalyst, thereby improving the photocatalytic degradation efficiency. Thus, this work provides a universal strategy to enhance the photocatalytic performance of Ti₂O₃ by coupling it with TiO₂ to build an internal electric field.

Self-Assembly of Bi2Sn2O7/β-Bi2O3 S-Scheme Heterostructures for Efficient Visible-Light-Driven Photocatalytic Degradation of Tetracycline

Fabrication of S-scheme heterojunctions with enhanced redox capability offers an effective approach to address environmental remediation. In this study, high-performance Bi₂Sn₂O₇/β-Bi₂O₃ S-scheme heterojunction photocatalysts were fabricated via the in situ growth of Bi₂Sn₂O₇ on β-Bi₂O₃ microspheres. The optimized Bi₂Sn₂O₇/β-Bi₂O₃ (BSO/BO-0.4) degradation efficiency for tetracycline hydrochloride was 95.5%, which was 2.68-fold higher than that of β-Bi₂O₃. This improvement originated from higher photoelectron-hole pair separation efficiency, more exposed active sites, excellent redox capacity, and efficient generation of ^·O₂ ^- and ^·OH. Additionally, Bi₂Sn₂O₇/β-Bi₂O₃ exhibited good stability against photocatalytic degradation, and the degradation efficiency remained >89.7% after five cycles. The photocatalytic mechanism of Bi₂Sn₂O₇/β-Bi₂O₃ S-scheme heterojunctions was elucidated. In this study, we design and fabricate high-performance heterojunction photocatalysts for environmental remediation using S-scheme photocatalysts.

Degradation of Tetracycline with Photocatalysis by CeO2-Loaded Soybean Powder Carbon

In the process of using photocatalysts to treat tetracycline (TC) wastewater, the degradation efficiency of soybean powder carbon material (SPC) can be improved by loading it with cerium oxide (CeO₂). In this study, firstly, SPC was modified by phytic acid. Then, the CeO₂ was deposited on modified SPC using the self-assembly method. Catalyzed cerium (III) nitrate hexahydrate (CeH₃NO₄) was treated with alkali and calcined at 600 °C under nitrogen. XRD, XPS, SEM, EDS, UV-VIS /DRS, FTIR, PL and N₂ adsorption-desorption methods were used to characterize the crystal structure, chemical composition, morphology, surface physical and chemical properties. The effects of catalyst dosage, monomer contrast, pH value and co-existing anions on TC oxidation degradation were investigated, and the reaction mechanism of a 600 Ce-SPC photocatalytic reaction system was discussed. The results show that the 600 Ce-SPC composite presents uneven gully morphology, which is similar to the natural "briquettes". The degradation efficiency of 600 Ce-SPC reached about 99% at 60 min under light irradiation when the optimal catalyst dosage and pH were 20 mg and 7. Meanwhile, the reusability of the 600 Ce-SPC samples showed good stability and catalytic activity after four cycles.