Search

Expanding the optical absorption range of photocatalysts is still a key endeavor in graphitic carbon nitride (g-C3N4) studies. Here, we report on a novel thiophene group extending the optical property, which is assigned to n-π* electronic transitions involving the two lone pairs on sulfur (TLPS). The as-prepared samples, denoted as CN-ThAx (where x indicates the amount of ThA added, mg), showed an additional absorption above 500 nm as compared to pristine g-C3N4. Further, the thiophene group enhanced charge carrier separation to suppress e−/h+ pair recombination. The experimental results suggest that the thiophene group can obstruct the polymerization of melem to generate a large plane, thus exposing the lone electron pairs on the sulfur. The photocatalytic activity was evaluated in the decomposition of bisphenol A and H2 evolution. Compared with g-C3N4, the optimized CN-ThA30 sample led to a 6.6- and 2-fold enhancement of the degradation and H2 generation rates, respectively. The CN-ThA30 sample allowed for synchronous H2 production and BPA decomposition.

Chemiresistive gas sensors with low power consumption, high sensitivity, and selectivity are of great significance for low-cost and efficient real-time gas detection. Herein, we present a highly se...

Evaluating the impact of increasing CO2 on rice quality is becoming a global concern. However, whether adjusting the source-sink ratio will affect the response of rice grain quality to elevated CO2 concentrations remains unknown. In 2016–2018, we conducted a free-air CO2 enrichment experiment using a popular japonica cultivar grown at ambient and elevated CO2 levels (eCO2, increased by 200 ppm), reducing the source-sink ratio via cutting leaves (LC) at the heading stage, to investigate the effects of eCO2 and LC and their interactions on rice processing, appearance, nutrition, and eating quality. Averaged across 3 years, eCO2 significantly decreased brown rice percentage (−0.5%), milled rice percentage (−2.1%), and head rice percentage (−4.2%) but increased chalky grain percentage (+ 22.3%) and chalkiness degree (+ 26.3%). Markedly, eCO2 increased peak viscosity (+ 2.9%) and minimum viscosity (+ 3.8%) but decreased setback (−96.1%) of powder rice and increased the appearance (+ 4.5%), stickiness (+ 3.5%) and balance degree (+ 4.8%) of cooked rice, while decreasing the hardness (−6.7%), resulting in better palatability (+ 4.0%). Further, eCO2 significantly decreased the concentrations of protein, Ca, S, and Cu by 5.3, 4.7, 2.2, and 9.6%, respectively, but increased K concentration by 3.9%. Responses of nutritional quality in different grain positions (brown and milled rice) to eCO2 showed the same trend. Compared with control treatment, LC significantly increased chalky grain percentage, chalkiness degree, protein concentration, mineral element levels (except for B and Mn), and phytic acid concentration. Our results indicate that eCO2 reduced rice processing suitability, appearance, and nutritional quality but improved the eating quality. Rice quality varied significantly among years; however, few CO2 by year, CO2 by LC, or CO2 by grain position interactions were detected, indicating that the effects of eCO2 on rice quality varied little with the growing seasons, the decrease in the source-sink ratios or the different grain positions.

Here, a simple one-step calcination method uses glycolic acid (GA) and urea to synthesize C-O band structure modified carbon nitride with broad spectral response, which is used to construct a peroxymonosulfate/visible light (PMS/vis) system. The solid-state

The Free Air CO

Broad spectrum light response and high photo-carrier separation efficiency are two key postulates for promising photocatalysts. In this perspective, polypyrrole (PPy) modified hexagonal SnS2 nanosheet composites were firstly designed via in-situ polymerization method and used for Cr(VI) reduction with broad spectrum light (UV–vis-NIR) driven. Results indicated that 15-PPy/SnS2 composite material not only has good photocatalytic performance in the visible region (λ > 420 nm), but also has a great improvement in the visible (λ > 550 nm) and near-infrared (λ > 760 nm). With the analysis of EIS, PL and transient photocurrent responses, PPy can observably accelerate the separation of electrons-holes pair in the photocatalytic reaction. Trapping experiments indicated that e− and O2− all played master roles in the photoreduction process. Based on the trapping experiments and the Mott-Schottky analysis, a possible mechanism is proposed. This work will provide a thinking to construct other SnS2-based photocatalysts for efficient Cr(VI) reduction with full spectrum light utilization.

A novel 3D PANI/MgIn2S4 nanoflower photocatalyst was synthesized for the wastewater treatment and energy conversion. In all composites, 1% 3D PANI/MgIn2S4 nanoflower composite exhibits the top-flight photocatalytic activity, which can be nearly 100% reduction of Cr (VI) after 30 min and nearly 97.0% of methyl orange (MO) is degraded in 50 min. At the same time, it was proved that the Cr (VI) was completely reduced by liquid ultraviolet and XPS. The as-prepared 3D PANI/MgIn2S4 nanoflower composites showed a significantly increased photocatalytic performance for hydrogen production under visible light irradiation. The photocatalytic mechanism illustrates that the introduction of polyaniline can prominently enhance the light absorption and promote effective separation of electron-hole pairs of the composites. PL spectrum and Transient photocurrent response show excellent photoinduced charge separation efficiency possess in 3D PANI/MgIn2S4 nanoflower. Electron spin response (ESR) technique and active species trapping experiments confirmed that e−, O2 and O2− played a very important role in the process of photoreduction of Cr (VI) and h+ and O2− were the principal active groups participated in photo-degradation of methyl orange (MO). In addition, the degradation process is accompanied by the generation of singlet oxygen (1O2) and hydrogen peroxide (H2O2), suggesting that these reactive oxygen species play a cardinal part in the photodegradation mechanism. The cycling and stable performance of 3D PANI/MgIn2S4 nanoflower also shows excellent photocatalytic effect. Such 3D PANI/MgIn2S4 nanoflower composite present a cracking strategy to enhance the photoactivity of the catalysts for wastewater treatment.

It is an urgent matter to eliminate antibiotics in waste water, due to the rapid emergence of antibiotic resistance. The search for low cost, high activity and stable novel photocatalysts has attracted great interest. Herein, we demonstrated the rational construction of CNT/LaVO4 nanostructures for efficient antibiotic photodegradation by a one-step hydrothermal method. The phase structures, chemical compositions, morphologies, and optical properties of the prepared samples were investigated via various characterization techniques. The optimized CNT/LaVO4 nanostructures exhibited efficient photodegradation activity with remarkable stability. The 0.1% CNT/LaVO4 showed the highest tetracycline degradation rate, which is 2 times that of pure LaVO4. Photoluminescence (PL), transient photocurrent response and electrochemical impedance spectroscopy (EIS) together verified that this design successfully expedites the separation and transfer of photogenerated charge carriers. Subsequently, by the electron spin resonance (ESR) spin-trap technique, free radical trapping experiments and mass spectrometry analysis (MS), the active species, intermediate product, photodegradation pathway and reaction mechanism during the photocatalytic process were identified. The antibacterial results showed that the degrading products have lower toxicity. The CNT/LaVO4 composite is a potential photocatalyst for improving the water quality.

Elevated atmospheric CO

Abundant active oxygen free radicals could efficiently remove refractory organic pollutants. In previous research, the original carbon nitride can form more hydrogen peroxide, however, owing to the limitation of its band structure, the original carbon nitride cannot decompose the hydrogen peroxide to generate more active oxygen free radicals. Herein, this work reports a simple bottom-up synthesis method, which synthesize a broad-spectrum-response carbon nitride (CN-CA) with oxygen-linked band and porous defect structure, while adjusting the band structure, and the introduction of the oxygen-linked band structure can also decompose the hydrogen peroxide produced by the original carbon nitride to form more active oxygen free radicals. Instrumental characterization and analysis of experimental results revealed the important role of oxygen-linked band and porous defects in adjusting the CN-CA energy band structure and improving its visible light absorption. The optimal CN-CA displays an outstanding photocatalytic degradation ability, that degradation rate of bisphenol A (BPA) reaches 99.8% within 150 min, the reaction rate constant of which is 6.77 times higher than that of pure g-C

Here, we successfully synthesized a brown carbon nitride (CY-C3N4) co-modified with oxygen bridge and porous defects via a universal acylation method. Excitingly, density functional theory (DFT) calculation shows that the introduction of oxygen bridges in the calcination polymerization process can adjust the electronic structure and energy band position of the new material. Further, the results of elemental analysis and X-ray photoemission spectroscopy test indicate that the oxygen bridge structure was successfully introduced into the skeleton of carbon nitride. The results show that 0.1CY-C3N4 can remove bisphenol A (BPA) and 2-mercaptobenzothiazole (MBT) with a removal rate of approximately 99% in 90 min and 20 min, respectively. Its degradation rate is 17.94 times and 3.85 times faster than that the original carbon nitride, respectively. Further, through HPLC-MS analysis, the intermediate products of the reaction process were analyzed in depth to propose a possible photocatalytic degradation route. Free radical capturing test and ESR spectroscopy indicate that the formative hydroxyl radical ( OH), superoxide radical ( O2–), singlet oxygen (1O2) and hole (h+) all play a key role in the photodegradation. This study provides a new way to synthesize brown carbon nitrides with oxygen bridges and porous defects for environmental applications.

In this study, a new type of carbon and oxygen co-doped g-C

Here, we successfully synthesized the oxygen-linked band and porous defect co-modified orange carbon nitride (AF-C3N4) using a simple method. Further, the band structure calculation of its simulated structure is performed by DFT, which shows that the introduction of oxygen-linked band can adjust its band structure. The photocatalytic degradation rates of 0.3AF-C3N4 for bisphenol A and 2-mercaptobenzothiazole were 8 times and 2.73 times that of the original g-C3N4, respectively. Moreover, 0.3AF-C3N4 also shows photocatalytic activity under different wavelength light (blue, green and red light), which indicates that the synthesized materials have a broad spectrum of photocatalytic activity. Further, we proposed a possible photocatalytic degradation pathway by HPLC-MS analysis. Free radical quenching test and ESR spectra show that the generated superoxide radicals (•O2−), hydroxyl radicals (•OH) and holes (h+) cause photodegradation, while enhancing singlet oxygen (1O2) and weaken the content of hydrogen peroxide has further proved that active oxygen groups play an important role in the photocatalytic degradation process. Additionally, the 0.3AF-C3N4 can also be a photoelectrochemical sensor to detect the concentration of bisphenol A (λ ≥ 550 nm). This study provides a new strategy for the synthesis of orange carbon nitride by oxygen-linked band and porous defect co-modification for photocatalytic applications.

Clarifying the genetic basis of trace element accumulation is of great significance to breed new maize varieties with high quality. In this study, an integrated variant map with 1.25 million (M) SNPs and 489 inbred lines was used for a genome-wide association study on the accumulation of iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), cadmium (Cd) and Arsenic (As) in maize kernels. Seventeen SNPs linked with six genes were overlapped by different trace elements. After further analysis, 65 SNPs located in 28 genes with a p-value lower than 10−10 were associated with Cd content by genome-wide association studies (GWAS). There was a 3.1-fold difference in Cd content between different groups, which was divided by SNP haplotype in chr2.S_160782359, chr2.S_161045498 and chr2.S_161273716. The amino acid sequences of GRMZM2G150608 and GRMZM2G051367 only shared 68.85% and 88.16% similarity between B73 and Mo17, and the Cd content of Mo17 was 2.2-fold that of B73. In addition, 19 lines with higher contents of Fe, Zn, Cu, Mn and fewer contents of As and Cd were screened from GWAS associated populations. This study will lay a foundation for revealing the molecular mechanism of trace element accumulation in maize kernels and provide candidate genes for breeding new maize varieties with high nutritional quality.

The Free Air CO2 Enrichment (FACE) facility enables the study of plant responses to climate change under open field conditions. This meta-analysis was conducted to quantitatively assess the effects of elevated CO2 concentration ([CO2]) on 47 variables describing rice growth physiology and whether CO2 effects were influenced by cultivar, plant growth stage, nitrogen application rate or temperature. On average, elevated [CO2] increased root and shoot biomass by 28% and 19%, respectively. Among shoot organs, the [CO2]-induced increase in leaf biomass was only 9%, significantly smaller than a 24% increase in stems or a 25% increase in panicles. The higher biomass for FACE rice was consistent with the stimulation in plant height (4%), maximum tiller number (11%), leaf area index (9%) and light-saturated photosynthetic rate (Asat, 22%). When compared within rice groups, hybrid rice showed the greatest CO2 response in growth and leaf physiological variables. Elevated [CO2] increased plant biomass and Asat at each rice growth stage, but the increment tended to decline with the advancement of rice growth and development. The increase in aboveground biomass at elevated [CO2] was enhanced by a higher nitrogen supply but reduced with a temperature elevation of 1–2 °C. Rice growth benefited more from elevated [CO2] in Chinese FACE studies than in Japanese FACE studies, which may result from the different cultivars and nitrogen application rates used in the two countries. Combined with a previous meta-analysis of the rice yield response to FACE, the [CO2] level predicted in the middle of this century will improve rice productivity by stimulating leaf photosynthesis. However, the effects of CO2 on the photosynthetic rate and rice growth tend to shrink over the plant life cycle. Selecting heat-resistant, high-yield hybrid rice cultivars with large sink capacity, supplemented with appropriate nitrogen input, will maximize the CO2 fertilizer effect in the future.

A high-performance photocatalyst should be superior not only in light absorption and charge transfer but also surface catalytic reaction. Here we report a green and simple strategy for evenly decorating Ag3PO4 particles using magnetic NiFe2O4 nanoparticles (NPs). The NiFe2O4 NPs could act as a magnetic support material for recycling the photocatalysts, as well as in situ catalytically decompose the H2O2 produced on the surface of Ag3PO4 into O2 − and OH radicals via a photo-Fenton process. The catalytic decomposition of H2O2 could produce strong oxidative capacity O2 − and OH radicals for the organic pollutants degradation and reduce host semiconductor holes ( h + ( A g 3 P O 4 ) ) consumption by these produced H2O2. Thus, the photocatalytic activities of Ag3PO4@NiFe2O4 composites were greatly enhanced. Taking the photocatalytic degradation of Methyl orange (MO), hardly decomposed colorless phenol compounds bisphenol A (BPA) and killing Escherichia coli (E. coli) as mode photocatalytic reactions, this system exhibited superior photocatalytic performances than that of pristine Ag3PO4. Electron spin resonance (ESR) spectroscopy and sacrificial-reagent incorporated photocatalytic characterizations indicated that the in situ eliminating/active decomposition of H2O2 produced by Ag3PO4 was the main reason for the enhanced photocatalytic activities.

Highly efficient different morphologies of SnS2 (nanoparticles, nanosheets, and 3D flower-like)/g-C3N4 composites were, respectively, prepared via an elementary hydrothermal method that was integra...

Novel 3D flower-like Ag2S/SnS2 composites were fabricated by a hydrothermal and ion exchange method. Uniform Ag2S quantum dots were homogeneously interspersed on 3D flower-like SnS2. The samples were characterized through X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) analysis. As expected, the as-prepared Ag2S quantum dot modified 3D flower-like SnS2 composites exhibited enhanced photoelectrochemical (PEC) performance and photocatalytic activities. The photocurrent density of 3% 3D flower-like Ag2S/SnS2 at 2.0 V (vs. Ag/AgCl) (0.65 mA cm−2) was about 3.25 times higher than that (0.2 mA cm−2) of 3D flower-like SnS2. The photocatalytic activity of 3D flower-like Ag2S/SnS2 composites was assessed through the degradation of methyl orange and the photocatalytic H2 evolution performance under visible light irradiation. The coupling of SnS2 and Ag2S quantum dots could notably promote the photocatalytic activity. The experimental results indicated that 3% 3D flower-like Ag2S/SnS2 composites showed the best photocatalytic performance for the degradation of methyl orange. These composites also exhibited a high H2 evolution rate of 574.7 μmol h−1 g−1 under visible light irradiation, approximately 5.57 times higher than that of pure 3D flower-like SnS2. Based on the calculation, radical trapping tests and ESR, a plausible mechanism for increased photoactivity was proposed. This work provides experimental insight into the design of low-cost photocatalysts for highly efficient photodegradation and photocatalytic H2-production.

The rational design of green and stable photocatalysts applied for highly efficient removal of antibiotics still remains a great challenge. In particular, the systematic analysis of the degradation pathway and toxicity of antibiotic degradation products is essential, but only few studies have been reported. Herein, novel GO/LaVO4 composite materials were fabricated via a facile one-step hydrothermal method, which presented enhanced photocatalytic degradation efficiency for tetracycline (TC) and naproxen (NPX) under visible light irradiation. It was found that 0.01% GO/LaVO4 presented the highest degradation rate with good stability, which is 3.46-times (for TC) and 2.29-times (for NPX) compared with that pure LaVO4. In particular, it is worth mentioning that the intermediates of TC produced during the photodegradation reaction and the corresponding possible degradation pathway were analyzed in depth by mass spectrometry (MS). More importantly, through the design of toxicology experiments, the toxicity of the TC solution was eliminated after the photocatalytic treatment. These results indicated that the modification of GO could efficiently improve the optical absorption property and accelerate the separation and migration of photogenerated charge carriers, thus enhancing the photocatalytic activity. This study offers a new perspective on the design of other LaVO4-based photocatalysts for efficient antibiotics’ removal.

In this work, a novel Ag 3 PO 4 @CoFe 2 O 4 composite photocatalyst was synthesized via a phosphate salts alkalinity adjustment strategy. Structure, morphology, and chemical component analysis indicated that the magnetic CoFe 2 O 4 nanoparticles (NPs) were evenly decorated on the surface of Ag 3 PO 4 particles, forming a sesame ball like structure. This unique structure ensures that the Ag 3 PO 4 @CoFe 2 O 4 composites could be totally separated by the magnet field. Photocatalytic water disinfection and organic pollutants degradation were employed to evaluate the photocatalytic performance of the as-prepared magnetic photocatalysts. The results showed that the optimum 3% Ag 3 PO 4 @CoFe 2 O 4 composite could completely inactivate 1*10 7 cfu/mL of Escherichia coli within 40 min, much faster than the pristine Ag 3 PO 4 . Meanwhile, the 3% Ag 3 PO 4 @CoFe 2 O 4 composite also showed a dramatic enhancement of photocatalytic activities for the organic pollutants degradation. The reactive oxygen species yield measurements, O 2 control photocurrents experiments, O 2 -TPD tests and photoluminescence spectra analysis indicate that the surface modification of CoFe 2 O 4 NPs could facilitate the O 2 adsorption and O O bond activation/cleavage/oxide removal and accelerate the two-electron oxygen reduction reaction for H 2 O 2 generation on the surface of Ag 3 PO 4 , and thus more ROSs were generated. In addition, due to the acceleration of electrons consumption, more holes will be left for the organic pollutants oxidation, and the photocatalytic activities as well as stability of Ag 3 PO 4 therefore have been greatly improved.

A novel visible-light driven ZnFe 2 O 4 /Ag/Ag 3 VO 4 photocatalyst was successfully fabricated through a two-step hydrothermal method. The structure, morphology and composition of the samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray photo-electron spectroscopy (XPS). The as-prepared ZnFe 2 O 4 /Ag/Ag 3 VO 4 composites possessed an excellent performance in the photocatalytic degradation of methyl orange and tetracycline under visible-light irradiation. The results of electrochemical impedance spectroscopy (EIS) indicated that the ZnFe 2 O 4 /Ag/Ag 3 VO 4 composite could facilitate the separation of photo-generated carriers, as well as accelerated charge transfer. The 5% ZnFe 2 O 4 /Ag/Ag 3 VO 4 composite exhibited the upmost photocatalytic activity, the degradation constant of 5% ZnFe 2 O 4 /Ag/Ag 3 VO 4 is as high as 1.49 times to that of Ag/Ag 3 VO 4 . Also, according to the trapping experiments, it’s found that the superoxide radicals ( O 2 − ) and hole (h + ) were the predominant reactive species in this system. The ZnFe 2 O 4 /Ag/Ag 3 VO 4 photocatalyst is promising for designing as an environmental purification material in treatment of antibiotic pollutant.

A novel visible-light-driven Ag2S/SnS2 composite photocatalyst was successfully fabricated via a simple in situ hydrothermal-ion-exchange method. The materials were systematically characterized by various techniques. XRD, XPS, and TEM analysis demonstrated the successful formation of Ag2S quantum dots on the surface of SnS2 nanoplates. The Ag2S/SnS2 composite materials exhibited increased photocatalytic activity compared to pure SnS2 for the removal of methyl orange (MO) and Cr(VI), and the 1% Ag2S/SnS2 composite material showed the best activity under visible light irradiation. Holes (h+) and superoxide radicals (˙O2−) were the major active species during the photocatalytic process. The in situ formation of Ag2S quantum dots provided an effective way to facilitate carrier transfer and separation, which is believed to be responsible for the enhanced photocatalytic performance.

Visible-light-driven magnetic CoFe2O4/Ag/Ag3VO4 photocatalysts with different weight ratios of CoFe2O4 were successfully synthesized by a hydrothermal method. The as-prepared samples have been characterized by X-ray diffraction (XRD), infrared (IR), scanning electron microscopy with an energy-dispersive X-ray spectroscope (SEM-EDS), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Ultraviolet–visible absorption spectroscopy (UV–vis) and vibrating sample magnetometer (VSM). The photocatalytic experiments indicate that the CoFe2O4/Ag/Ag3VO4 composites possess enhanced visible-light-driven photocatalytic activity towards the degradation of methyl orange (MO), tetracycline (TC) and killing Escherichia coli (E. coli). Electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) spectra analysis indicate that the introduction of CoFe2O4 could efficiently promote the separation efficiency of photogenerated charge carriers in Ag/Ag3VO4. It is obvious that the composites show better photocatalytic activity than the pure Ag/Ag3VO4 and CoFe2O4. In particular, the 5% CoFe2O4/Ag/Ag3VO4 sample shows the highest photocatalytic activity and the degradation constant of 5% CoFe2O4/Ag/Ag3VO4 is as high as 3.4 times to that of Ag/Ag3VO4. The trapping experiments show that O2− and h+ are the major reactive species for the CoFe2O4/Ag/Ag3VO4 photocatalytic system. In addition, the as-prepared CoFe2O4/Ag/Ag3VO4 composite can be quickly separated from the solution by an extra magnetic field after the photocatalytic reaction. The cyclic test and the XRD patterns before and after cyclic test show that the CoFe2O4/Ag/Ag3VO4 hybrid materials have the stable degradation ability and crystal structure during the photodegradation process. Furthermore, it shows highly efficient visible light photocatalytic antibacterial activity. In all, the CoFe2O4/Ag/Ag3VO4 photocatalyst, as the magnetic photocatalyst and antibacterial, is promising for the further practical application of photocatalysis in wastewater treatment.

For the first time, herein this work, we have developed an effective and adaptable method to introduce defects onto the polymeric carbon nitride by simply grinding urea with urea nitrate which resulting new carbon nitride composite (UNU-C3N4) and melamine with urea nitrate which resulting new carbon nitride composite (UNM-C3N4). The UNU-C3N4 reveals high performance towards photocatalytic hydrogen production and as well as photocatalytic removal of contaminants. The results confirm that the defects enhanced the specific surface area, and improved performance of adsorbed oxygen which beneficial to generate more active radicals and more conducive sties to improve d the overall photocatalytic performance. The high N, H, and O content-enhanced electron polarization effects, by introducing the additional N, H, and O atoms into the g-C3N4 matrix, which will increase the charge transfer rate and charge separation efficiency. At the same time, the results of ESR also expression that the new type of as-prepared carbon nitride samples exhibit abundant of hydrogen radical (H ) formation, which is also assist to improve the photocatalytic hydrogen production performance. As expected, the H2 evolution rate of UNU-C3N4(or UNM-C3N4) underneath simulated solar light irradiation is 9.93 times (13.76 times) than that of U-C3N4 (urea as raw material) (or M-C3N4 (melamine as raw material)). The high hydrogen evolution rates of UNU-C3N4 and UNM-C3N4 are 830.94 and 556.79 μmol g−1 h−1 under the visible-light irradiation, respectively. Meanwhile, the synthesized UNU-C3N4 and UNM-C3N4 material are demonstrated an efficient ability to degrade pollutants. In general, this work provides a viable way to introduce defects and hydrogen bands into the structure of carbon nitride.

Photoreduction of highly toxic Cr(VI) has been regarded as an efficient and green method to achieve water purification. In this process, better charge carrier separation is vital to achieving excellent performance. Besides, it is vital to systematically explore the influencing factors and reaction mechanism. Herein, a novel 3D PPy/Zn

Abundant active oxygen free radicals could efficiently remove refractory organic pollutants. In previous research, the original carbon nitride can form more hydrogen peroxide, however, owing to the limitation of its band structure, the original carbon nitride cannot decompose the hydrogen peroxide to generate more active oxygen free radicals. Herein, this work reports a simple bottom-up synthesis method, which synthesize a broad-spectrum-response carbon nitride (CN-CA) with oxygen-linked band and porous defect structure, while adjusting the band structure, and the introduction of the oxygen-linked band structure can also decompose the hydrogen peroxide produced by the original carbon nitride to form more active oxygen free radicals. Instrumental characterization and analysis of experimental results revealed the important role of oxygen-linked band and porous defects in adjusting the CN-CA energy band structure and improving its visible light absorption. The optimal CN-CA displays an outstanding photocatalytic degradation ability, that degradation rate of bisphenol A (BPA) reaches 99.8% within 150 min, the reaction rate constant of which is 6.77 times higher than that of pure g-C3N4, as also demonstrated with 2-mercaptophenthiazole (MBT) and ciprofloxacin (CIP). Meanwhile, the excellent degradation performance under blue LED (450–462 nm) and green LED (510–520 nm) exhibits the broad-spectrum characteristics of CN-CA. The degradation pathways of BPA and MBT were analyzed via HPLC-MS. Moreover, the primary active species were detected as O2−, OH and h+ based on the trapping experiments and ESR. This research provides a new strategy for g-C3N4 modified by porous defects and oxygen-linked band structure for environmental remediation.

Elevated atmospheric CO2 (EC) and temperature (ET) strongly affect agricultural production, but the mechanism through which EC and/or ET influence starch granules and their relationship to cooked rice taste remain largely unknown. Therefore, a field experiment using a popular japonica cultivar grown in a temperature/free-air CO2 enrichment environment was conducted to investigate the responses of volume and fine structure of starch granules and their formation physiology to EC (+200 ppm) and/or ET (+1 °C) in 2015–2016. EC markedly enhanced the activity of soluble-starch synthase and granule-bound starch synthase by 28.0% and 27.9% respectively, thereby increasing the long chains and the volume of starch granules. However, EC decreased the activity of starch-branch enzyme by 7.5% possibly via the pathway of ethylene signalling (EC prominently decreased the ethylene evolution rate of rice grains by 28.8%), resulting in a remarkable decrease in α-1′6 glucosidic bonds and significant increase in the iodine-binding capacity and double helix in starch molecules. These EC-induced changes in morphology and fine structure of starch granules synergistically altered the thermal properties of rice flour and eventually improved the cohesiveness and taste of cooked rice, as suggested by the significant relationships between them. ET partially offset the beneficial EC effects in most cases. However, few remarkable CO2 × temperature or CO2 × year effects were detected, indicating that the effects of EC on starch granules and rice taste less varied with meteorological conditions. These findings have important implications on rice palatability and for the development of adaptive strategies in the starch industry in future environment.

Designing a green and efficient catalyst to effectively degrade antibiotics is still one of the hot topics of research. Firstly, 1D nanorod Fe2O3/NaNbO3 composite was successfully prepared by the two steps strategy through hydrothermal combined calcination method. In addition, the photocatalytic activity of the samples was evaluated by the degradation of tetracycline (TC) under visible light irradiation. The test results show that the 5% Fe2O3/NaNbO3 nanorod material exhibits superior degradation rate of TC (89.4% removal efficiency in 90 min), and shows 5.62 times than that of NaNbO3 nanorods. Under UV–visible light irradiation, 5% Fe2O3/NaNbO3 nanorod composite with H2O2 solution can degrade 97.4% of TC in 60 min, which is 12.1 times greater to that of the pure NaNbO3 nanorods. The outstanding degradation performance may be attributed to the introduction of Fe2O3 nanoparticles, which can activate H2O2 more efficiently and produce more free radicals to degrade pollutants. At the same time, the 5% Fe2O3/NaNbO3 nanorod composite can also act as an activate persulfate (PS) and generate SO4 − to efficiently degrade TC. In addition, the catalyst also showed good performance in degrading TC in the presence of different anions and cations. Plant growth experiment (mung bean seeds) results showed that the degradation products have obvious lower toxicity. This study provides new domain about the designing of a photo-Fenton catalyst having dual ion synergy (Fe3+/Fe2+ and Nb5+/Nb4+) and full spectrum response.

The rapidly increasing atmospheric CO2 is accompanied by global warming. However, the effects of the elevated CO2 concentration (EC) and/or air temperature (ET) on starch morphology, structure and thermal properties which considerably contribute to the taste of cooked rice have not been reported to date. Therefore, a field experiment using a temperature/free-air CO2 enrichment facility was conducted with EC (+200 ppm) and/or ET (+1 °C) treatments from 2014 to 2016. The surface area of starch granules and proportion of large starch granules were significantly increased by EC and ET, but the most significant increases of 3.4% and 5.9%, respectively, were induced by the combined treatment. EC did not change the crystalline type but altered the order structure of starch molecules: EC averagely decreased the ratios of 1045/1022 and 1022/995 cm−1 by 2.6% and 3.3% respectively, however, significantly increased the crystallinity by 4%. For most cases, EC significantly increased the gelatinization temperature and pasting viscosity of starch, decreased setback, enthalpy and protein content and eventually improved rice taste. Results of correlation analysis suggested that EC affected the thermal properties of starch and the taste of cooked rice mainly by improving the size and molecule order structure of starch granules. Small and few significant ET and EC × ET effects were detected, indicating that the EC influence will be predominant in future climate. These findings will help in improving rice palatability and developing the starch industry.

Bi3.64Mo0.36O6.55/CuBi2O4 composite was firstly synthesized by decorating Bi3.64Mo0.36O6.55 nanoparticles on the CuBi2O4 nanorods. The photo-Fenton-like system of copper-based composite catalyst was fabricated for highly efficient degradation pollution. The composite can catalyze the decomposition of H2O2 and improve Cu+ generation efficiency. Bi3.64Mo0.36O6.55/CuBi2O4 catalyst showed an excellent degradation activity for tetracycline hydrochloride more than 3.5 times higher than pure CuBi2O4, and the photo-degradation rate closed to 82.7% degradation after 30 min. The trapping experiments and electron spin resonance demonstrated that OH, O2– and h+ played an important role in the Bi3.64Mo0.36O6.55/CuBi2O4 system. Moreover, the effects of pH value, H2O2, catalyst content and pollution concentration on the photo-degradation over this system were explored. Furthermore, the system still had high activity for photo-degradation of other organic pollutants such as rhodamine B, methyl orange and methylene blue. This study has supplied a neoteric method to construct copper-based heterogeneous photo-Fenton-like catalysts for effective photo-degrading pollutant.

In this study, a new type of carbon and oxygen co-doped g-C3N4 (PACN) was successfully synthesized by a one-step thermal polymerization method for the photodegradation of Bisphenol A (BPA) and selective oxidation of toluene to benzaldehyde. The degradation rate of BPA was 23.58 times higher than that of pristine g-C3N4 and the efficiency benzaldehyde formation rate without the need of any solvent increased to 5.43 times that of g-C3N4. At the same time, the band structure calculation of its simulated structure is performed by DFT, which shows that the introduction of oxygen linking band can adjust its band structure and obtain a smaller band gap. In addition, the PACN displays an enhanced photocatalytic degradation of BPA under the long wavelength (λ ≥ 550 nm) and NIR light irradiation (λ ≥ 760 nm), which indicates that the synthesized materials have a broad spectrum of photocatalytic activity. According to the results of secondary ion mass spectrometry (SIMS) and nuclear magnetic resonance spectroscopy (NMR), C atoms and O atoms were introduced into the original g-C3N4 skeleton. In addition, the intermediate products were detected by mass spectrometry (HPLC-MS), and the BPA degradation pathway was proposed. A feasible photocatalytic reaction mechanism was also proposed.

The increase of atmospheric carbon dioxide (CO2) concentration adversely affect several quality traits of rice grains, but the biochemical mechanism remains unclear. The objectives of this study were to determine how changes in the source-sink relationship affected rice quality. Source-sink manipulation was achieved by free-air CO2 enrichment from tillering to maturity and partial removal of spikelet at anthesis using a japonica rice cultivar Wuyunjing 23. Enrichment with CO2 decreased the head rice percentage and protein concentration of milled rice, but increased the grain chalkiness. In contrast, spikelet removal resulted in a dramatic increase in the head rice percentage and protein concentration, and much less grain chalkiness. Neither CO2 enrichment nor spikelet removal affected the starch content, but the distribution of starch granule size showed distinct treatment effects. On average, spikelet removal decreased the percentage of starch granules of diameter >10 and 5–10 µm by 23.6 and 5.6%, respectively, and increased those with a diameter of 2–5 and 5 µm) and decreasing that of

Rising tropospheric ozone concentrations in Asia affect the yield and quality of rice. This study investigated ozone-induced changes in rice grain quality in contrasting rice genotypes, and explored the associated physiological processes during the reproductive growth phase. The ozone sensitive variety Nipponbare and a breeding line (L81) containing two tolerance QTLs in Nipponbare background were exposed to 100 ppb ozone (8 h per day) or control conditions throughout their growth. Ozone affected grain chalkiness and protein concentration and composition. The percentage of chalky grains was significantly increased in Nipponbare but not in L81. Physiological measurements suggested that grain chalkiness was associated with a drop in foliar carbohydrate and nitrogen levels during grain filling, which was less pronounced in the tolerant L81. Grain total protein concentration was significantly increased in the ozone treatment, although the albumin fraction (water soluble protein) decreased. The increase in protein was more pronounced in L81, due to increases in the glutelin fraction in this genotype. Amino acids responded differently to the ozone treatment. Three essential amino acids (leucine, methionine and threonine) showed significant increases, while seven showed significant treatment by genotype interactions, mostly due to more positive responses in L81. The trend of increased grain protein was in contrast to foliar nitrogen levels, which were negatively affected by ozone. A negative correlation between grain protein and foliar nitrogen in ozone stress indicated that higher grain protein cannot be explained by a concentration effect in all tissues due to lower biomass production. Rather, ozone exposure affected the nitrogen distribution, as indicated by altered foliar activity of the enzymes involved in nitrogen metabolism, such as glutamine synthetase and glutamine-2-oxoglutarate aminotransferase. Our results demonstrate differential responses of grain quality to ozone due to the presence of tolerance QTL, and partly explain the underlying physiological processes.

Background Rising atmospheric CO2 is accompanied by global warming. However, interactive effects of elevated CO2 and temperature have not been well studied on grain quality of rice. A japonica cultivar was grown in the field using a free-air CO2 enrichment facility in combination with a canopy air temperature increase system in 2014. The gas fumigation (200 µmol mol(-1) above ambient CO2 ) and temperature increase (1 °C above ambient air temperature) were performed from tillering until maturity. Results Compared with the control (ambient CO2 and air temperature), elevated CO2 increased grain length and width as well as grain chalkiness but decreased protein concentrations. In contrast, the increase in canopy air temperature had less effect on these parameters except for grain chalkiness. The starch pasting properties of rice flour and taste analysis of cooked rice indicated that the palatability of rice was improved by CO2 and/or temperature elevation, with the combination of the two treatments showing the most significant changes compared with ambient rice. Conclusion It is concluded that projected CO2 in 2050 may have larger effects on rice grain quality than the projected temperature increase. Although deterioration in milling suitability, grain appearance and nutritional quality can be expected, the taste of cooked rice might be better in the future environment. © 2015 Society of Chemical Industry.

Core–shell magnetic Ag/AgCl@Fe2O3 photocatalysts were synthesized using a two-step method. The introduced Fe2O3 can be effectively dispersed on the surface of the Ag/AgCl. The Fe2O3 on the surface can act as a shell to prevent the inactivation of the inner Ag/AgCl by bisphenol A (BPA). The composites were investigated by XRD, SEM-EDS, XPS, UV-vis, VSM, and so on, which confirmed that the core–shell magnetic Ag/AgCl@Fe2O3 was successfully obtained. The EIS and PL results suggest that the composite has better electron–hole separation ability, which is beneficial for enhancing the photoactivity. The degradation of the BPA solution results show that the 5% Ag/AgCl@Fe2O3 has the highest photoactivity, the degradation rate of which is as high as about 13 times that of pure Ag/AgCl. Besides, the composites still have much better degradation ability than the pure Ag/AgCl in each cycle experiment. The photocatalytic antibacterial experiment showed that the composite could completely kill the pathogenic microorganism E. coli under visible light irradiation at 30 min. The results suggest that the core–shell magnetic Ag/AgCl@Fe2O3 can be used as an effective magnetic recyclable photocatalyst in eliminating the colorless pollutant bisphenol A and microbial contamination. Furthermore, a possible reaction mechanism was proposed based on the trapping experiments and the ESR results.

In this study, a new type of high-performance visible light photocatalyst Fe2O3/Ag3VO4 was prepared by a two-step method. Fe2O3 was prepared by a solvothermal method first and then the Fe2O3/Ag3VO4 photocatalyst was synthesized with different mass ratios by a simple chemical precipitation method. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectrometry (EDS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-vis absorption spectroscopy (in DRS mode), and electrochemical impedance spectroscopy (EIS) were applied to characterize the as-prepared samples. The results showed that the as-prepared photocatalyst was uniform in the shape of particles. Photocatalytic properties of the as-prepared samples were evaluated by degrading RhB under visible light. The results showed that 1% Fe2O3/Ag3VO4 composite presented the highest photocatalytic activity. After 60 min, 96.1% of RhB was degraded by 1% Fe2O3/Ag3VO4 composite. Finally, trapping experiments confirmed that the hole (h+) and superoxide free radical (˙O2−) were the main active species in degrading RhB.

CNT/AgI composite with the diameter smaller than 1 µm was synthesized through a solvothermal method. The CNT/AgI hybrids were characterized by XRD, SEM, XPS, UV-Vis, photocurrent and so on. The results showed that the introduced CNT can greatly reduce the particle size of AgI without using surfactant. Besides, the introduced CNT transferred the electrons efficiently and enhanced the photoactivity of the CNT/AgI hybrids in degrading RhB dye. 0.3% CNT/AgI showed the highest photocatalytic activity, which was as high as about 2 times that of pure Ag/AgI. Trapping experiments and the electron spin resonance (ESR) results suggested the reactive species in the degradation process were h+, ˙OH and ˙O2−. Furthermore, the CNT/AgI still showed high photoactivity after 4 cycle experiments. Photocatalytic antibacterial experiments showed that the 0.3% CNT/AgI had better antibacterial ability than pure Ag/AgI. The results showed that the CNT/AgI can be used as a dual functional material in water treatment of removing the organic pollutant and killing the bacterium at the same time.

Consistent design and cost-effective multifunctional electrocatalyst that comprises of highly abundant earth elements are greatly need for sustainable energy conversion applications. The present study reports a facile single-step strategy for in-situ growth of NiFeCo nanoparticles doped-ultrathin carbon nanosheets (NFC@CNSs) with hierarchical like structure by pyrolysis method. NFC@CNSs catalyst at optimum condition exhibits an outstanding activity with a low overpotential 124 and 256 mV to achieve a current density of 10 mA cm-2 with a small tafel slope 119.22 and 67.83 mV dec-1 for hydrogen and oxygen evolution reactions, respectively, in 1.0 M KOH. Furthermore, NFC@CNSs exhibits the large electrochemical active surface area of 21.30 mF cm-2, highly specific SBET surface area 145.39 m² g-1, low charge transfer resistance 46.87 ohms which forms the superior catalytic performance. The two-electrode system constructed as anode and cathode in an alkaline electrolyzer can achieve a current density of 10 mA cm-2 by a fairly low applied cell-voltage of 1.566 V under the real water splitting condition. The result revealed that, the strong coupling between NiFeCo alloy nanoparticles and carbon nanosheets might have been responsible for formulating such a remarkable electrochemical performances, electronic structure, and robust stability toward overall water splitting. Additionally, ultrathin porous carbon nanosheets structure does not only provides substantial active sites, but also facilitates the charge transfer process during diffusion and saturation of electrolytes which ultimately boost-up catalytic performances. This work provides a facile single-pot approach to construct metal-doped nanostructured materials with earth-abundant elements for sustainable industrial applications.

Herein, a novel direct Z-scheme mechanism of red carbon nitride/rod-like LaVO4 (RCNL) photocatalyst was prepared by a simple hydrothermal method. Under visible light irradiation, the photocatalytic degradation experiments on tetracycline (TC) and naproxen (NPX) showed that 5% RCNL material presented the best photocatalytic performance, which was 3 times (TC) and 2.69 times (NPX) higher than pure LaVO4, respectively. The degradation process of tetracycline and naproxen was further analyzed by mass spectrometry, and their possible degradation routes were proposed. The antibacterial results (against Escherichia coli) showed that the degrading products have lower toxicity. The analysis of band structure, electron spin resonance technique and free radical trapping experiments showed that the h+ at valence band of RCN and e- at the conduction band of LaVO4 participated in the final photocatalytic redox process to achieve high redox ability for the rapid degradation of pollutants.

Here, a series of BaFe12O19/AgBr magnetic recyclable composites were designed for the removal of 2‑Mercaptobenzothiazole (MBT) and Methyl orange (MO) under visible light. The vibrating sample magnetometer test demonstrated that composites exhibit superior magnetic recyclability. Among all composites, 10% BaFe12O19/AgBr exhibited the highest reaction rate (0.1005 min−1) of MBT degradation, which was about 3.32 and 71.79 times higher than that of pure AgBr (0.0302 min−1) and BaFe12O19 (0.0014 min−1), respectively. Besides, the composites also exhibited obviously improved photocatalytic MO degradation properties. The excellent photocatalytic activity could be ascribed to the efficient separation of photo-induced charge carriers, which was certificated by cyclic voltammogram (CV), transient photocurrent tests, electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) spectra. Capture experiments proved that O2−, h+ and OH are the main active species in the process of MBT degradation, which matches well with the results of electron spin resonance (ESR) measurements. Moreover, the test of Mott-Schottky plots verified the flat band potentials of catalysts. At last, a possible Z-scheme reaction mechanism for the photocatalytic system was proposed. This work will provide theoretical guidance for the construction of magnetically recyclable Z-type photocatalysts.