Herein, Cu was incorporated into ZnO lattice to reduce its band gap as well as to extend its visible radiation response. The obtained Cu-ZnO was continuously integrated with g-C3N4 to create ...Cu-ZnO/g-C3N4Z-direct scheme photocatalyst for advanced atrazine removal. Radical scavenging experiments have been also conducted to clearly figure out photocatalytic mechanism for degradation of atrazine by the synthesized photocatalyst. The synthesized Cu-ZnO only utilized the generated h+ for atrazine degradation (direct and indirect via formation hydroxyl radicals (•OH)) and the g-C3N4 only utilized the generated e− for atrazine degradation (indirect via reaction with O2 to form superoxide anion, which needed to continuously react with H2O to form •OH). Therefore, the photocatalytic atrazine degradation by synthesized Cu-ZnO material was greater than that by synthesized g-C3N4 material. Cu-ZnO/g-C3N4 utilized both generated e− and h+ for degradation of atrazine. Thus, the photocatalytic atrazine degradation by the synthesized Cu-ZnO/g-C3N4 was greater than those of single g-C3N4 or Cu-ZnO materials. Finally, the conducted recycling experiments indicated great stability of synthesized Cu-ZnO/g-C3N4 during long-term atrazine degradation process opening new era for application of the material in practical systems.
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•Cu doped into ZnO lattice to reduce its band gap and to extend its visible radiation response.•Cu-ZnO was successfully combined with g-C3N4 to establish Z direct scheme system.•Z-scheme prevented fast recombination of e− and h+ and maintained their re-dox potential.•The Cu-ZnO/g-C3N4 utilized both generated e− and h+ for degradation of atrazine.•The Cu-ZnO/g-C3N4 showed excellent activity and stability during long-term photocatalysis.
ZnO/graphene oxide (ZnO/GO) nanocomposites were synthesized by hydrothermal method using zinc acetate and graphite as precursors. Properties of synthesized materials were investigated by different ...physico-chemical techniques and their photocatalytic performance was evaluated with the aid of the photodegradation of methyl orange under UV irradiation. Impacts of reaction conditions such as pH of solutions, catalyst loading and initial concentration on photodegradation rate of synthesized photocatalysts were also investigated. TEM images showed that the average size of the synthesized ZnO was approximately 35 nm, being in good agreement with the obtained XRD results which revealed good dispersion of ZnO particles over the wrinkled GO layers. UV–Vis absorption spectra of these synthesized materials revealed that 5% ZnO/GO exhibited the highest visible light absorption. Photocatalytic experimental results showed that the highest photodegradation rates occurred in a neutral solution with an initial methyl orange (MO) concentration of 10 mg/L. After 2 h of reaction under UV irradiation, more than 95% of MO was degraded at optimal conditions. The photodegradation of MO followed the pseudo-first-order kinetics with apparent reaction rate constants in the range of 0.009–0.030 (min
−1
). ZnO/GO photocatalyst was relatively stable in neutral aqueous solutions during the photodegradation of MO, with a decrease of 6% in photocatalytic performance observed after four cycles compared with the first cycle.
We successfully used Cu to dope into the NiWO4 crystal to prevent the fast recombination or increase the lifetime of the photo-induced h+ and e− of the material. Then, the synthesized Cu-NiWO4 was ...successfully hybridized with g-C3N4 to form Cu-NiWO4/g-C3N4 direct Z system for novel photocatalytic decomposition of n-hexane under vis-light. In the formed Cu-NiWO4/g-C3N4 Z direct system, photo-induced e− in Cu-NiWO4 CB associated with photo-induced h+ in g-C3N4 VB maintaining e− in g-C3N4 CB and h+ in Cu-NiWO4 VB, thereby synthesized photocatalysts formed abundant available e− and h+ amounts even excited by vis-light and the formed e− and h+ pairs exhibit suitable redox potentials for reactions with O2 and H2O, respectively, to produce strong oxidative radicals for advanced photocatalytic degradation of n-hexane. The highest removal efficiency and degradation degree of n-hexane photocatalyzed by Cu-NiWO4/g-C3N4 were 96.8 and 96.3%, respectively. The synthesized Cu-NiWO4/g-C3N4 material also demonstrated strongly stability during long time n-hexane removal.
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•Successfully doped Cu into NiWO4 lattice to enhance its photocatalytic activity.•Cu dopant prevented recombination of photo-excited e− and h+ of the NiWO4.•Cu-NiWO4 was successfully combined with g-C3N4 to establish Z direct scheme system.•Z-scheme prevented fast recombination of e− and h+ and remained their oxidative ability.•The Cu-NiWO4/g-C3N4 exhibited excellent photocatalytic degradation of gaseous n-hexane.
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•Successfully doped Cu into ZnO lattice to enhance its photocatalytic activity.•Cu dopant prevented recombination of photo-excited e− and h+ of the ZnO.•The Cu-ZnO exhibited excellent ...photocatalytic degradation of monocrotophos pesticide.•The optimal mole ratio of Cu/ZnO in the Cu-ZnO for degradation of monocrotophos was 3%.•The optimal pH for the photocatalytic degradation of monocrotophos was pH 7.
In the work, we successfully synthesized Cu doped ZnO materials for photocatalytic degradation of monocrotophos pesticide (MCP). The used Cu metal doped into the ZnO matrix created an intermediate band to excite electron from valence band (VB) to conduction band (CD) of the ZnO leading to increase in optical absorption, decrease in band gap as well as photocatalytic performance of the material. Hence, the synthesized photocatalyst showed intense activity for photocatalytic degradation of MCP into CO2, H2O and harmless inorganic ions even under visible radiation. We also investigated that the 3Cu-ZnO photocatalyst, which the weight ratio of Cu/ZnO was 3 wt%, showed the highest MCP degradation efficiency among these synthesized Cu-ZnO. The excess dopants tended to form CuO existing on ZnO surface. The formed CuO acted as a center for recombination of produced electrons and holes resulted in decrease in photocatalytic performance of the Cu-ZnO. Finally, we investigated that the optimal pH for the degradation of MCP by the synthesized Cu doped ZnO photocatalyst was pH 7.
In the study, we used two conducting polymers, polyaniline (PANI) and polypyrrole (PPy), to sensitize Ta3N5, thereby enhancing its photocatalytic activity, and then applied this novel photocatalyst ...to overall water splitting to produce hydrogen and oxygen even under visible light irradiation. The two polymers increased the charge transfer efficiency, prevented the recombination of the generated electrons and holes of the Ta3N5 photocatalyst, and thereby enhanced its electron-hole separation efficiency and improved its photocatalytic activity for efficient visible light water splitting. The two polymers completely covering the Ta3N5 particles facilitated charge transfer for quick migration of the generated electrons and holes to the polymer surface and thus prevented contact between the holes and nitride of Ta3N5. Therefore, these conducting polymers also protected the Ta3N5 particles from self-photocorrosion during long-term water splitting. Because of the existence of the protonated nitrogen (-N+) state in PPy, the electric conductivity of PPy was lower than that of PANI, which lowered the sensitizing ability of PPy compared to that of PANI. Thus, the water splitting efficiency of Ta3N5/PANI was higher than that of Ta3N5/PPy. The production rates of H2 and O2 generated from water splitting of Ta3N5/PANI were 60.5 and 30.2 (μmol. g−1cat. h−1), respectively.
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•Polymer sensitizers enhanced the separation of e−/h+ pairs and prolonged the Ta3N5 lifetime.•Polymer cover protected Ta3N5 from self-photocorrosion (oxidation of generated holes).•Ta3N5/polymers greatly exhibited overall photocatalytic water splitting.•Lower electric conductivity lowered the sensitizing ability of the polymer.•PANI was better than PPy for enhancing the photocatalytic activity of Ta3N5.
Herein, g-C3N4 and NiMoO4, which are moderate energy band gap semiconductors, have been effectively hybridized to create Z scheme heterojunction for successful visible-light photocatalytic converting ...CO2 into valuable products including CH4, CO, O2 and HCOOH. Ni(NO3)2·6H2O and (NH4)6Mo7O24·4H2O were used as precursors to synthesize NiMoO4 photocatalyst, which was continuously mixed with melamine before calcinating at 520 °C for 6 h to get NiMoO4/g-C3N4 Z scheme heterojunction. We explored that NiMoO4 intimately contacted with g-C3N4. These band positions of the NiMoO4 were also perfectly matched with those of the g-C3N4. Therefore, these photo-induced e− on conduction band of the NiMoO4 could easily travel to h+ on valence band of the g-C3N4 (recombination); thereby, minimize h+ and e− recombination in each material. Therefore, the NiMoO4/g-C3N4 direct Z-scheme heterojunctions could produce significant available h+ on the valence band of the NiMoO4 and e− on the conduction band of the g-C3N4. These e−/h+ have suitable redox potential to effectively convert CO2. Finally, the optimized g-C3N4 mole ratio for maximum enhancing photocatalytic efficiency of the NiMoO4/g-C3N4 heterojunction was 60%. When the g-C3N4 content increased to 70%, the excess g-C3N4 amount would entirely cover NiMoO4 surface leaded to form dense and closed shell. The formed closed shell decreased contact between NiMoO4 and CO2 as well as the interface charge transfer, which reduced the e− and h+ separation and transfer leading to decrease in photocatalytic conversion efficiency.
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•Successfully created NiMoO4/g-C3N4 Z scheme heterojunction for CO2 conversion.•Hybridization of NiMoO4 and g-C3N4 prevented recombination of e−/h+ in each material.•The created NiMoO4/g-C3N4 converted CO2 into HCOOH, CH4 and CO even under visible light.•The optimal molar ratio of g-C3N4/NiMoO4 for the best photocatalytic conversion was 60%.
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In this study, we firstly aimed to use Nb as dopant to dope into the TiO2 lattice in order to narrow band gap energy or enhance photocatalytic activity of the Nb-TiO2. Then, the ...prepared Nb-TiO2 was combined with g-C3N4 to establish Nb-TiO2/g-C3N4 direct Z-scheme system for superior reduction of CO2 into valuable fuels even under visible light. The obtained results indicated that the band gap energy of the Nb-TiO2 (2.91 eV) was lower than that of the TiO2 (3.2 eV). In the successfully established Nb-TiO2/g-C3N4 direct Z-scheme system, the photo-excited e− in the CB of the Nb-TiO2 combined with the photo-excited h+ in the VB of the g-C3N4 preserving the existence of e− in the CB of the g-C3N4 and h+ in the VB of Nb-TiO2, and thereby, the system produced numerous amount of available e−/h+ pairs for the reduction of CO2 into various valuable fuels. In addition, the produced e− of the Nb-TiO2/g-C3N4 existing in the CB of the g-C3N4, which the potential energy is approximately −1.2 V, would be strong enough for the reduction of CO2 to generate not only CH4 and CO but also HCOOH. Among established Nb-TiO2/g-C3N4 materials, the 50Nb-TiO2/50 g-C3N4 material was the best material for the CO2 reduction.
Exopolysaccharides (EPSs) are biological polymers secreted by microorganisms including Lactic acid bacteria (LAB) to cope with harsh environmental conditions. EPSs are one of the main components ...involved in the formation of extracellular biofilm matrix to protect microorganisms from adverse factors such as temperature, pH, antibiotics, host immune defenses, etc.. In this review, we discuss EPS biosynthesis; the role of EPSs in LAB stress tolerance; the impact of environmental stresses on EPS production and on the expression of genes involved in EPS synthesis. The evaluation results indicated that environmental stresses can alter EPS biosynthesis in LAB. For further studies, environmental stresses may be used to generate a new EPS type with high biological activity for industrial applications.
Rambutan (Nephelium lappaceum L.) peel (RBP) is discarded as the main by‐product during processing of the fruit. Increasing attention is now paid to the valorization of RBP for the recovery of ...valuable compounds. Geraniin, ellagic acid, quercetin, and rutin are the main phenolic compounds found in methanolic RBP extract. Extracted rambutan peel powder (ERPP) is used to evaluate the oxidative stability of soybean oil stored at 4 and 30 °C in the dark and light and deep fried with potatoes at 160 °C. Tert‐butylhydroquinone (100 µg g−1 oil, TBHQ) serves as positive control. Oil supplemented with ERPP of 1000 µg gallic acid equivalents (GAE) g−1 of oil shows positive effects on the retardation of the oxidation process during storage in comparison with oil without addition. During deep frying, either ERPP (1000 µg GAE g−1) or TBHQ retards the lipid oxidation of oil. Levels of thiobarbituric acid reactive substances of potatoes fried in oil fortified with the extract and TBHQ (0.4–0.59 µg g−1) are much lower than those without the extract (1.31 ± 0.10 µg g−1) (p < 0.05). Therefore, RBP extract exhibits favorable antioxidant effects and can be used for effectively inhibiting lipid oxidation in oil during storage and deep frying.
Practical Applications: An extract from rambutan fruit peel containing phenolic compounds, that is, geraniin, ellagic acid, rutin, and quercetin showed promising results to be used as potential antioxidants in soybean oil during deep frying. Both oxidation of the frying oil as well as the oxidation of the food product, that is, potatoes were inhibited. These results demonstrated that rambutan fruit peel extract can be used as a natural antioxidant in frying oil to replace synthetic antioxidants, that is, TBHQ.
Flowchart of antioxidant activity of phenolic compounds from rambutan peel extract during oil storage and deep frying.
The paraflocculus and the neighboring smaller flocculus form a remarkable protrusion in the ventrolateral aspect of the mouse cerebellum, in which the longitudinal compartments are conspicuously ...oriented perpendicularly to the sagittal plane. The developmental process of such anatomical arrangements in these lobules has not been fully clarified. Here, we used the genetic tractability of pcdh10‐lacZ knock‐in (OL‐KO), IP
3R1‐nls‐lacZ transgenic (1NM13) and Gpr26cre‐Ai9‐AldocV mice to track the development of compartments and examined local longitudinal orientation of Purkinje cells within the paraflocculus and flocculus. We observed a distinct pcdh10‐positive (pcdh10+) compartment in the flocculus, whereas the paraflocculus and other lobules had a continuous paravermal pcdh10+ compartment, in the embryonic OL‐KO cerebellum. During the first postnatal week, the parafloccular pcdh10+ compartment shifted laterally to the most lateral edge in the caudal part of the protruding paraflocculus. Although the most medial edge of the parafloccular pcdh10+ compartment remained in the nonprotruding part of the paraflocculus, it was disrupted from the originally continuous pcdh10+ compartment in the copula pyramidis. The local longitudinal orientation changed gradually along with the mediolateral extent of the copula pyramidis, almost becoming perpendicular to the sagittal plane in the laterally connected paraflocculus in the adult cerebellum. This rotational change in orientation was derived from the short U‐shaped embryonic cerebellum, in which the surfaces of the flocculus and paraflocculus were oriented laterally. These results indicated that the peculiar compartmental organization of the paraflocculus originates from the embryonic common hemispheric compartmental organization and shaped by the significant reorganization process in the first postnatal week.
The paraflocculus (PFl), neighbored by the flocculus (Fl) and copula pyramidis (Cop), forms remarkable protrusion between postnatal Days 1 and 7 (P1, P7) in the mouse cerebellum. The paravermal compartment of pcdh10+ Purkinje cells (arrowheads) migrate laterally to become accommodated within the laterally oriented striped compartmentalization in the bulb‐shaped paraflocculus.
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