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Bi2O2CO3 (BOC) was successfully loaded on a highly conductive Ti3C2 surface by the hydrothermal method, forming a unique BOC/Ti3C2 heterostructure. The use of advanced characterization methods reveals the composition, morphology and photoelectric properties of the material. The results show that the interface formed by close contact between BOC and Ti3C2 provides an effective channel for charge transfer between the two. Importantly, the photocatalytic degradation efficiency of BOC/Ti3C2 for tetracycline (TC) is ~80%, which is significantly higher than the degradation efficiency of pure BOC and pure Ti3C2 for TC. In addition, BOC/Ti3C2 still has high catalytic activity in the degradation of complex mixed antibiotics. This is because BOC and Ti3C2 have large specific surface areas, high light absorption capacity and efficient carrier separation after recombination. At the same time, the detected superoxide radicals (O2-) and holes (h+) are the main active substances. The degradation pathway and catalytic mechanism of the photocatalytic degradation of TC by BOC/Ti3C2 are further explained. This research designed and developed a BOC/Ti3C2 composite material for the photocatalytic degradation of tetracycline and mixed antibiotic wastewater, providing experimental methods and ideas for actual wastewater treatment.

Solar energy can be used as "green" energy by photocatalysis for the nitrogen fixation under the atmospheric conditions compared with the traditional energy-intensive industrial production of ammonia. However, the complex kinetics and high reaction barriers greatly hinder the development of the photocatalytic N2 reduction reaction. Herein, a BiOBr/MXene-Ti3C2 composite catalyst is prepared by the simple electrostatic adsorption and self-assembly method. The as-prepared 10 wt % BiOBr/Ti3C2 exhibits the best performance for N2 fixation to NH3 by photocatalysis. The evolution rate of NH3 is up to 234.6 μmol·g-1·h-1, which is approximately 48.8 times and 52.4 times higher than those of pure BiOBr and Ti3C2, respectively. It is found that the designed double vacancies of oxygen and titanium for BiOBr/Ti3C2 composites, with the availability of localized electrons, have the ability to adsorb and activate N2, which can be efficiently reduced to NH3 by the interfacial electrons transferred from the excited BiOBr/Ti3C2 composite. In addition, the results of in situ Fourier transform infrared show the generation of NxHy species by the continuous protonation processes. Moreover, titanium vacancy (VTi) induces a strong absorption energy for nitrogen atoms on the surface of BiOBr/Ti3C2 according to the density functional theory calculations. In particular, the P-electron feedback caused by VTi could effectively promote the weakening of the N≡N triple bond and elongate the N2 bond length by ∼31.6%. This work might provide new insights into the synergistic effect of double defects and inspiration for the rational design of catalysts by defect engineering in the field of catalytic synthesis of ammonia.

Solar energy can be used as "green" energy by photocatalysis for the nitrogen fixation under the atmospheric conditions compared with the traditional energy-intensive industrial production of ammonia. However, the complex kinetics and high reaction barriers greatly hinder the development of the photocatalytic N

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Eucommia ulmoides flavones (EUF) have been demonstrated to alleviate oxidative stress and intestinal damage in piglets, but their effect target is still poorly understood. NF-E2-related factor 2 (Nrf2) pathway plays a very important role in the defense mechanism. This study was designed to investigate the regulation of EUF on the Nrf2 pathway and inhibition of Nrf2 on oxidative stress in the intestine of piglets. An in vivo study was conducted in weaned piglets treated with basal diet, basal diet+diquat, and 100 mg/kg EUF diet+diquat for 14 d to determine Nrf2 and Keap1 protein expressions, as well as downstream antioxidant gene mRNA expression. An in vitro study was performed in a porcine jejunal epithelial cell line to investigate the effect of inhibiting Nrf2 on cell growth and intracellular oxidative stress parameters. The results showed that the supplementation of EUF decreased the oxidized glutathione (GSSG) concentration and the ratio of GSSG to glutathione (GSH) but increased the protein expressions of nuclear Nrf2 and Kelch-like ECH-associated protein 1 (Keap1) as well as mRNA expression of heme oxygenase 1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO-1), and glutamate cysteine ligase catalytic subunit (GCLC) in the small intestinal mucosa of diquat-challenged piglets. When Nrf2 was inhibited by using ML385, cell viability, cellular antioxidant activities, expressions of nuclear Nrf2 and Keap1 protein, and downstream antioxidant enzyme (HO-1, NQO-1, and GCLC) mRNA were decreased in paraquat-treated enterocytes. These results showed that the Nrf2 signaling pathway played an important role in EUF-regulating oxidative stress in the intestine of piglets.

In this paper, a two-step method was used to successfully construct a CaFe2O4/ZnCo2O4 composite photocatalyst. XRD, TEM, XPS, PL, EIS, etc., were used to characterize the morphological structure, element state, photoelectric response and other characteristics of the material. Tetracycline (TC) was used as the target pollutant to evaluate the photocatalytic performance of the composite photocatalyst. The results showed that in the best reaction system (ZC-30), the TC degradation rate reached 88% within 100 min of light exposure, while that in the CaFe2O4 system was only 17%. The TC degradation rate with ZC-30 is 11.26 times and 2.21 times higher than that with CaFe2O4 and ZnCo2O4, respectively. The main reason is that the close contact between CaFe2O4 and ZnCo2O4 can effectively separate and transfer the light-induced carriers, which improves the photocatalytic activity of the catalyst. The SEM and XRD results and the cycling experiments results confirmed that the synthesized photocatalyst showed good stability after 3 cycles. CaFe2O4/ZnCo2O4 can be used for oxytetracycline and chlortetracycline degradation with a good degradation rate. Moreover, the composite photocatalyst was systematically studied in the TC degradation system to analyze the possible TC degradation pathway, the effective active substances and a reasonable catalytic mechanism.

The overuse of sulfonamides, causing serious pollution of water bodies, has drawn great attention from society. To address these problems, a novel CuFe2O4/MXene (CFO/Ti3C2) heterojunction photocatalyst was used to photodegrade the antibiotic sulfamethazine (SMZ, a typical pollutant) under visible light, and the synergy and coupling function of the two components in the heterojunction system were analyzed. With the aid of time-resolved photoluminescence (TRPL) and transient surface photovoltage (TPV) spectra, the carrier lifetimes and kinetic behaviors were studied, revealing that the lifetime of photoinduced carriers was prolonged by loading Ti3C2, inhibiting the reorganization of photogenerated electron holes. More importantly, the organic intermediates and mineralization degree were identified by high-performance liquid chromatography (HPLC)-mass spectrometry (MS) and total organic carbon (TOC) techniques. The results show that the breaking of SN bonds, the oxidation of aniline and deamination were dominated by the attack of •OH. This work shows a new model for the degradation mechanism of SMZ over CFO/MXene heterostructures.