Visible-light-driven Ag/Bi3O4Cl nanocomposite photocatalyst with enhanced photocatalytic activity for degradation of tetracycline

In this study, a novel Ag/Bi3O4Cl photocatalyst has been synthesized by a facile photodeposition process. Its photocatalytic performance was evaluated from the degradation of tetracycline (TC) under visible light irradiation (λ > 420 nm). The 1.0 wt% Ag/Bi3O4Cl photocatalyst could significantly enhance the degradation of TC compared with pure Bi3O4Cl, with the degradation level reaching 94.2% in 120 minutes. The enhancement of photocatalytic activity could be attributed to the synergetic effect of the photogenerated electrons (e−) of Bi3O4Cl and the surface plasmon resonance (SPR) caused by Ag nanoparticles, which could improve the absorption capacity of visible light and facilitate the separation of photogenerated electron–hole pairs. In addition, electron spin resonance (ESR) analysis and trapping experiments demonstrated that the superoxide radicals (˙O2−), hydroxyl radicals (˙OH) and holes (h+) played crucial roles in the photocatalytic process of TC degradation. The present work provides a promising approach for the development of highly efficient photocatalysts to address current environmental pollution, energy issues and other related areas

Synthesis of mesoporous g-C3N4/S-PAN π-conjugation heterojunction via sulfur-induced cyclization reaction for enhanced photocatalytic H2 production

Simultaneously extended π-conjugated system and provide abundant pore structure of semiconductor photocatalysts for hydrogen (H2) production is highly desirable. Hence, a novel mesoporous sulfurized polyacrylonitrile modified g-C3N4 (g-C3N4/S-PAN) π-conjugation heterojunction is firstly fabricated by one-step strategy under the sulfur-induced cyclization reaction and pore-creating effect. Excitedly, the g-C3N4/S-PAN π-conjugation heterojunction extends the π-conjugated system in favor of speeding up the photogenerated electron transfer, which is due to strengthen the π-π interactions between the S-PAN and g-C3N4 and S-PAN is more apt to accept electrons. And the obtained g-C3N4/S-PAN π-conjugation heterojunction with mesoporous structure also provide abundant active sites for proton reduction. Accordingly, the g-C3N4/S-PAN-2 π-conjugation heterojunction shows the optimal photocatalytic H2 evolution (PHE) activity (736.24 μmol h−1g−1), which is approximately 2.15 times higher than pristine g-C3N4. In addition, the relationships of the optical and photoelectrochemical properties with photocatalytic activity are revealed in depth based on the first-principles calculations of band structure and density of states (DOS). This work provides a new one-step strategy to obtain g-C3N4-based π-conjugation heterojunction with the unique microstructure for improving PHE activity

Construction of Spinel/Perovskite Heterojunction for Boosting Photocatalytic Performance for Polyacrylamide

The use of photocatalytic technology to degrade polyacrylamide in crude oil extraction wastewater is a promising approach, but there have been few reports so far. In this study, ZnFe2O4/Ba0.7Sr0.3TiO3 heterogeneous composite materials of a spinel/perovskite type with different proportions were synthesized. The composite materials with 31% ZnFe2O4 content exhibited a maximum polyacrylamide degradation efficiency of 46.54%, which demonstrated the unique role of the spinel/perovskite heterogeneous structure. When Ag nanoparticles were grown in situ on the surface of ZnFe2O4/Ba0.7Sr0.3TiO3, the photocatalytic degradation efficiency reached 81.28%. The main reason was that the introduction of Ag nanoparticles not only increased the active sites and enhanced light absorption capacity but also accelerated the separation of photo-generated charges. This work provides new ideas for the construction of spinel/perovskite heterogeneous composite materials and has reference significance for the application of photocatalytic degradation in the treatment of wastewater-containing polymers

Precursor-reforming strategy induced g-C3N4 microtubes with spatial anisotropic charge separation established by conquering hydrogen bond for enhanced photocatalytic H2-production performance

Precursor-reforming strategy induced graphitic carbon nitride (g-C3N4) with different morphologies for enhanced photocatalytic hydrogen (H2) evolution activity is highly desirable. Herein, g-C3N4 microtubes (mg-C3N4) with adjustable closure degree of microtube orifice and spatial anisotropic charge separation are established by conquering hydrogen bond during thermally exfoliate precursor. Compared to the bulk g-C3N4 (bg-C3N4) and ultrathin g-C3N4 (ug-C3N4), the tubular structure endows mg-C3N4 with spatial anisotropic charge separation that accelerates transfer of charge carriers. As expected, the photocatalytic H2 evolution (PHE) activity of mg-C3N4 has been obviously enhanced. Particularly, the mg-C3N4-24 shows the best PHE activity (957.9 μmol h−1 g−1), which is over 18.72 and 3.77 times higher than the bg-C3N4 and ug-C3N4, respectively. In addition, selective photo-deposition experiment results reveal a charge carriers migration behavior that photoproduction electrons migrate to the outer shell and holes prefer to move onto the inner shell of mg-C3N4, thus achieving efficient spatial anisotropic charge separation. We firmly believe that the work presents significant advancement for the design of other materials by precursor-reforming strategy

Construction of SrTiO3/Bi2O3 heterojunction towards to improved separation efficiency of charge carriers and photocatalytic activity under visible light

In this paper, the novel SrTiO3/Bi2O3 heterostructures photocatalysts were fabricated by a facile microwave process, and the visible-light-driven photocatalytic activity has been investigated for tetracycline (TC) degradation. The as-synthesized of SrTiO3/Bi2O3 photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis diffuse reflection spectroscopy (DRS). The photocatalytic performance was evaluated by the degradation TC under visible light irradiation (λ > 420 nm). Compared to pristine SrTiO3 and Bi2O3, the as-prepared SrTiO3/Bi2O3 samples exhibited remarkably enhancing photocatalytic activity for degradation of TC. It was found that the 50% SrTiO3/Bi2O3 heterojunction showed the highest photocatalytic efficiency for TC degradation, and the degradation rate could reach 85% in 140 min. The enhanced photocatalytic activity was attributed to the formation of a heterojunction between SrTiO3 and Bi2O3, which could greatly improve the transfer and separation of charge carriers in the two-phase interface. Meanwhile trapping experiments indicated that the h+ and radical dotOH were the main active species

Facile Synthesis of a Polycatenane Compound Based on Ag-triazole Complexes and Phosphomolybdic Acid for the Catalytic Epoxidation of Olefins with Molecular Oxygen

A simple and efficient approach was developed for synthesizing a metal-organic polycatenated compound composed of Ag-triazole complexes and phosphomolybdic acid (PMA) clusters. The hybrid compound, namely {[Ag2(trz)2] [Ag24(trz)18]}[PMo12O40]2 (1) (trz = 1,2,4-triazole), showed high catalytic activity, selectivity and recyclability for the epoxidation of olefins with molecular oxygen as the oxidant and isobutyraldehyde as the co-reagent, and could even work well under ambient conditions. The special polycatenane framework, formed by interlocking [Ag24(trz)18]6+ nanocages, provides suitable space for filling the PMA clusters. The existence of multi-interactions, including π-π stacking, Ag-Ag interactions, and electrostatic interactions, should play a determinative role in fabricating the catalytically active and stable PMA-based polycatenane catalyst for aerobic epoxidation of olefins

Ni2P QDs decorated in the multi-shelled CaTiO3 cube for creating inter-shelled channel active sites to boost photocatalytic performance

Control and insight into the abundance of inter-shelled channel active sites and charge transport mechanism are the long-term challenges for enhancing photocatalytic activity. Herein, the Ni2P quantum dots (QDs) are decorated in the multi-shelled CaTiO3 cube for creating the abundance of inter-shelled channel active sites, which greatly improve the photocatalytic performances for generating H2 and degrading tetracycline (TC) relative to pure CaTiO3 and Ni2P. Moreover, the Z-scheme mechanism and the quantum effect of the Ni2P in multi-shelled CaTiO3 cube play a crucial role for enhancing photocatalytic performance. Furthermore, the photoelectric researches demonstrate that the Ni2P/CaTiO3 heterostructure possesses more abundant active sites, smaller interface transmission resistance and faster photo-generated charge transfer efficiency. This work provides a meaningful model to research other materials with creating the abundance of inter-shelled channel active sites for the photo-electrocatalytic field

Effects of oil quality and antioxidant supplementation on sow performance, milk composition and oxidative status in serum and placenta

Abstract Background The aim of this study was to determine the effects of oil quality and antioxidant (AOX) supplementation on sow performance, milk composition and oxidative status. Methods A total of 80 PIC (PIC breeding, 3 ~ 5 parities) sows with similar body condition were allocated to four groups (n = 20), receiving diets including fresh corn oil, oxidized corn oil, fresh corn oil plus AOX and oxidized corn oil plus AOX, respectively, from d 85 of gestation to d 21 of lactation. AOX was provided at 200 mg/kg diet and mixed with corn oil prior to dietary formulation. Results The results showed that sows fed oxidized corn oil had significantly lower feed intake (P < 0.05) during lactation period. Feeding oxidized corn oil markedly decreased (P < 0.05) the contents of protein and fat in colostrums and milk, but the addition of AOX in oxidized corn oil prevented the decrease on protein content of colostrums. Moreover, sows fed oxidized corn oil had significantly lower serum activities of total SOD and Mn-SOD across lactation (P < 0.05). In contrast, addition of AOX to oxidized corn oil tended to inhibit the production of MDA (P = 0.08) in sows across lactation relative to fresh oil. Intriguingly, the placental oxidative status was affected by oil quality and AOX supplementation, as indicated by the markedly increased placental gene expression of GPX and SOD (P < 0.05) in sows fed oxidized corn oil but normalized by supplementation of AOX. Conclusion In conclusion, feeding oxidized corn oil did not markedly affect reproductive performance in addition to decreasing feed intake during lactation. Milk composition and systemic oxidative status were deteriorated in sows fed oxidized corn oil and partially improved by AOX supplementation. Moreover, placental antioxidant system of sows may have an adaptive response to oxidative stress, but normalized by AOX