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Photocatalytic conversion of CO2 into methanol using graphitic carbon nitride under solar,UV laser and broadband radiations 下载免费PDF全文
Photocatalytic conversion of carbon dioxide into methanol using highly efficient g‐C3N4, in conjunction with three different radiations (solar radiation, broad‐band ultraviolet (UV)–visible lamp, and laser beam) is presented. The optical, structural, and morphological properties of the synthesized g‐C3N4 were studied using advanced analytical techniques like Fourier transform infrared spectroscopy, UV–visible spectrometer, X‐ray diffraction, high‐resolution transmission electron microscopy, high‐angle annular dark field, and X‐ray photoelectron spectroscopy. The relative merits of the three sources of radiation in the presence of g‐C3N4 were studied in terms of key figures of merit of the photocatalytic process, namely, methanol production yield and quantum yield. As expected, after 40 min of irradiation, 355‐nm laser (40 mJ/pulse, 10 Hz) with g‐C3N4 rendered the best methanol production yield (510 μmol g ? 1 h ? 1), followed by solar radiation (130 μmol g ? 1 h ? 1), and UV broadband lamp. This indicates that the photon flux and the spectral properties of incident light are the key factors for the enhancement of methanol production yield. Although the methanol production yield with 355‐nm laser radiation is quite impressive because of the inherent high photon flux and the monochromatic nature of laser, the methanol yield of 130 μmol g ? 1 h ? 1 with natural sunlight is quite an important result, as it can be used for the development of large‐scale solar fuel generation facilities by harnessing the naturally abundant solar radiation. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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Alessandro C. Martins Lais BukmanAlexandro M.M. Vargas Érica O. BarizãoJuliana C.G. Moraes Jesuí V. VisentainerVitor C. Almeida 《Food chemistry》2013
This study proposes a FRAP assay adapted to FIA system with a merging zones configuration. The FIA system conditions were optimised with the response surface methodology using the central composite rotatable design. The optimisation parameters studied were: the carrier flow rate, the lengths of the sample and reagent loops, and reactor length. The conditions selected in accordance with the results were: carrier flow rate of 1.00 ml/min, length of the loops 18.2 cm and length of the reaction coil 210.1 cm. The detection and quantification limits were, respectively, 28.6 and 86.8 μmol/l Fe2+, and the precision was 1.27%. The proposed method had an analytical frequency of 30 samples/h and about 95% less volume of FRAP reagent was consumed. The FRAP assay adapted to the FIA system under the optimised conditions was utilised to determine the antioxidant activity of tea samples. 相似文献
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Luciane Madureira Almeida Juliana Ferreira Floriano Thuanne Pires Ribeiro Lais Nogueira Magno Lígia Souza Lima Silveira da Mota Nei Peixoto Fátima Mrué Paulo Melo-Reis Ruy de Souza Lino Junior Carlos Frederico de Oliveira Graeff Pablo José Gonçalves 《Journal of materials science. Materials in medicine》2014,25(9):2153-2162
The latex obtained from Hancornia speciosa is used in folk medicine for treatment of several diseases, such as acne, warts, diabetes, gastritis and inflammation. In this work, we describe the biocompatibility assessment and angiogenic properties of H. speciosa latex and its potential application in medicine. The physical–chemical characterization was carried out following different methodologies (CHN elemental analyses; thermogravimetric analyses and Fourier transform infrared spectroscopy). The biocompatibility was evaluated through cytotoxicity and genotoxicity tests in fibroblast mouse cells and the angiogenic properties were evaluated using the chick chorioallantoic membrane (CAM) assay model. The physical–chemical results showed that the structure of Hancornia speciosa latex biomembrane is very similar to that of Hevea brasiliensis (commercially available product). Moreover, the cytotoxicity and genotoxicity assays showed that H. speciosa latex is biocompatible with life systems and can be a good biomaterial for medical applications. The CAM test showed the efficient ability of H. speciosa latex in neovascularization of tissues. The histological analysis was in accordance with the results obtained in the CAM assay. Our data indicate that the latex obtained from H. speciosa and eluted in water showed significant angiogenic activity without any cytotoxic or genotoxic effects on life systems. The same did not occur with H. speciosa latex stabilized with ammonia. Addition of ammonia does not have significant effects on the structure of biomembranes, but showed a smaller cell survival and a significant genotoxicity effect. This study contributes to the understanding of the potentialities of H. speciosa latex as a source of new phytomedicines. 相似文献
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This work focuses on the technical and technological aspects of fusion welding of high-manganese steels exhibiting twinning-induced plasticity (TWIP) for both similar and dissimilar joints. Changes in the alloy chemistry resulting from evaporation and dilution are discussed with respect to stacking fault energy and austenite stability. The influence of fusion welding on grain size and strength is also discussed. Conclusions are drawn with respect to optimization processes for fusion welding of TWIP steel. 相似文献
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非对称数字用户线路(ADSL)系统是目前部署的消费类DSL系统中最受欢迎的形式。它可在较短的环路中支持最大达12Mbps水平的数据速率。在环路延长至5.5Km或更长的情况下,通过调节其速率与频谱,仍可实现有意义的数据速率。但是,许多干扰降低了ADSL的覆盖范围,这就在网络中形成漏洞,无法实现可接受的服务速率。 相似文献
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Using a second generation enzyme immunoassay (ELISA) for the detection of antibodies against Hepatitis C virus (HCV), we investigated the frequency of antibodies anti-HCV and the Alanine Aminotransferase (ALT) plasma levels of 200 patients without history of viral hepatitis, liver diseases, blood transfusions, intravenous drugs abuse, homosexuality, hemodialysis, infection by Human Immunodeficiency Virus (HIV), Hepatitis B virus (HBV), nor workers of health services. There plasma samples (1.5%), were positives for antibodies anti-HCV, all of these samples were confirmed by RIBA (Recombinant Immunoblot Assay). In these three patients, the ALT plasma level were more than two folds the normal upper limit, another six patients had high ALT levels but less than one fold the normal upper limit. None of the infected patients had any clues that suggested the possible way of infection in the clinic history. We concluded that the incidence of Hepatitis C in the studied patients is 1.5% and that the ALT levels could be used to identify Hepatitis C infection. 相似文献
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Manuel F.R.P. Alves Lais G. Abreu Gesinete G.P. Klippel Claudinei Santos Kurt Strecker 《Ceramics International》2021,47(1):301-309
In this work, the properties of yttria-stabilized zirconia-based ceramics, Y-TZP containing Fe2O3 as coloring agent were evaluated. Nanoparticled powder of 3Y-TZP (ZrO2 - 3 mol.% Y2O3) doped with different amounts of Fe2O3 (0.002–0.136 wt%) were compacted into monolithical or multilayered samples and sintered at 1475 °C - 2 h. The samples were characterized by X-ray diffraction analysis (XRD), relative density, scanning electron microscope (SEM). Hardness and fracture toughness in the color interface were investigated using the Vickers indentation method and the biaxial flexural strength was determined by the piston on 3 balls method (P–3B). Furthermore, optical parameters were measured using spectrophotometry in regard to sample thickness and Fe2O3 content. The results indicated a good adhesion between layers, proven by indentation cracks randomly growing between different regions, because the powders used produced very similar morphological characteristics. The different amounts of Fe2O3 studied in this work did not interfere in densification, phase composition, or microstructure of the sintered ceramics. The fracture toughness and flexural strength did not significantly change due to the addition of Fe2O3, presenting values close to 7 MPa m1/2 and 1120–1150 MPa, respectively, in all studied compositions. On the other hand, increasing Fe2O3 contents lead to an increase in the hardness of the material (1280–1330 H V), and higher contrast ratios (CR) with a consequent loss of translucency. Color variation (ΔE) depended also on the thickness of the material. 相似文献