查看更多>>摘要：The low-cost and highly-efficient photocatalysts for solar-light induced water splitting had drawn great attention to develop the renewable hydrogen economy. To enhance the solar-light driven H-2 evolution of Mn0.5Cd0.5S, Mn0.5Cd0.5S was modified by S,N-codoped carbon (3-MCS/SN-C) via the in-situ sulfurization at high temperature. In contrast with Mn0.5Cd0.5S (11.13 mmol g(-1) h(-1)) and S-doped g-C3N4 (0.35 mmol g(-1) h(-1)), the optimal 3-MCS/SN-C with a mass ratio of Mn0.5Cd0.5S to S,N-codoped carbon of 1:3 exhibited the best H-2 evolution rate of 27.58 mmol g(-1) h(-1) and an apparent quantum yield of 27.43% at 400 nm. The photo-corrosion induced to the decreased H-2 evolution capacity of 3-MCS/SN-C from 131.13 to 126.52 mmol g(-1) after five cycles of 5 h. S,N-codoped carbon could efficiently capture vis-ible light and absorb the photons, leading to the efficient transformation and separation of photo-generated carriers at the junction interface between Mn0.5Cd0.5S and S,N-codoped carbon. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
Park, Ju HyangSung, Kyung EunKim, Ki HakKim, Jong Ryeol...
10页
查看更多>>摘要：This work reports the fabrication of AuNR@MSNs [i.e., gold nanorods (AuNRs) coated with mesoporous silica nanoshells (MSNs)] with independent sensitivities to pH and near-infrared (NIR) light for reversible on-off switching of drug release without premature drug leakage. The fabrication involves the incorporation of lauric acid (LA) as a thermosensitive gatekeeper, followed by the coating of tannic acid (TA) layers as a pH-sensitive gatekeeper. The protonation-deprotonation of the TA layers according to change in pH can result in their swelling-deswelling to induce pH-sensitive drug release, while the solid-liquid phase transition of LA by NIR light-induced heat generation in AuNRs enables the NIR light-controlled release of preloaded drug molecules. The interplay between these dual gatekeepers allows the release of pre-loaded drug from the AuNR@MSN-LA@TAs (i.e., AuNR@MSNs incorporating LA and TA) only at acidic conditions under NIR light irradiation, without premature drug leakage under inactive conditions (neutral pH or no NIR light). Moreover, the reversibility of the gatekeepers can make an on-off mannered drug release. Benefiting from the capability of the gatekeepers to induce pH-/temperature-sensitive release, along with the photothermal ability of AuNRs, the AuNR@MSN-LA@TAs can exhibit a satisfactory anticancer performance without undesired drug leakage. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：A new route for synthesizing polydiacetylene (PDA) is introduced. Plasma is generated in a liquid matrix through a pair of electrodes, producing the excited atomic or molecular species, radicals, and UV radiation. The products of solution plasma process (SPP) act as initiators to induce polymerization of diacetylene monomers. Our results demonstrate that irreversible thermochromic PDA and reversible thermochromic PDA/Zn2+/ZnO nanocomposite can be effectively synthesized. The addition of ethanol significantly increases the polymerization rate. These PDA materials can be fabricated into paper-based colorimetric sensors for detecting volatile organic solvents, acids, bases, and surfactants. This synthetic pathway could be applied for industrial-scale applications. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：In this work, synthesis of CuIn0.75Ga0.25S2 (CIGS) nanoparticles, the formation of stable dispersion, deposition of high-quality films and, fabrication of thin-film Perovskite solar cells are reported. The stability of nanoparticle ink is crucial in the formation of device-quality films. The chalcogenide-based materials are widely used in thin-film solar cells; in particular, Cu(In,Ga)S-2 are used as an absorber and hole transporting layer. In the present study, the nanoparticles of about 20 nm size and bandgap of 1.5 eV are synthesized using a heat-up method. A variety of solvents are used as dispersing media and the stability of the inks is evaluated by precise optical monitoring. We observe a clear dependence of ink stability to the polarity index of the solvent, where the best stability occurs at a polarity index of about 0.26-0.36, corresponding to a range of solvents including chloroform. The thin films that are spin-coated using CIGS chloroform ink show large cracks, presumably due to the high vapor pressure of chloroform and evaporation-induced stress in the film. We resolve this problem through low-temperature deposition, which resulted in highly uniform pin-hole and crack-free films. Finally, the optimum deposition condition is used to fabricate perovskite solar cells having about 16.5% efficiency with CIGS as a hole transport layer. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：In this study, tetraethyl orthosilicate (TEOS) was synthesized by the continuous reaction of metallurgical silicon (MSi) with ethanol. The results obtained herein suggest that among all the alkali metal base catalysts, diethylene glycol monoethyl ether sodium (DEGEE-Na) is the best catalyst; this is because it does not require any extra diethylene glycol monoethyl ether (DEGEE-H) as excess DEGEE-H results in its decomposition products. It is present in a solid phase at room temperature; however, it changes into a liquid phase under the reaction conditions. In contrast, DEGEE-Li was not suitable for this reaction, whereas DEGEE-K required extra DEGEE-H as a solvent because of the solidification of the reaction mixture in the reaction with MSi. When the continuous reaction was carried out by feeding ethanol into a mixture of MSi and DEGEE-Na salt catalyst (1:1 wt.% ratio) at 175 degrees C, TEOS was obtained with a yield of 70.6%. In addition to TEOS, small amounts of byproducts, such as (2-ethoxyethoxy)triethoxysilane and hexaethoxydisiloxane were obtained and unreacted ethanol was recovered and recycled. For the preparation of TEOS, activation of MSi is an important step in the reaction with ethanol. We believe that this continuous process for preparing TEOS is more economically competitive and eco-friendly method. (c) 2021 Published by Elsevier B.V. on behalf of The Korean Society of Industrial and Engineering Chemistry.
查看更多>>摘要：For accurate and reproducible MFC experiments, it is important to know when MFCs produce stable cell performance. Herein, four replicate single-chamber MFCs were tested for 17 weeks by using polarization and cyclic voltammetry (CV) tests. The strong MFCs (#2,4,3) showing continuous performance enhancement initially (3rd-9th week) produced good subsequent performance (9th-17th week). The weak MFC-1 experienced a performance drop initially and showed bad subsequent performance. All the MFC performance became stable after 9 weeks. The strong MFCs produced power 2.8-3.6 times higher and anode resistance 7.5-23.9 times lower than the weak. However, their cathode resistances were similar. CV results showed anodic current production increased continuously in all MFCs, indicating anode biofilms kept growing;, MFC performance did not increase accordingly. Anodic CVs had a typical S-shape curve, but those of MFC-1 showed straight lines from the 9th week. The weak MFC-1 showed smaller CV currents and thinner CV curves than those of the strong MFCs. In MFC-1, at the 17th week, the anode resistance reduced by 47%, anodic current and cell performance increased. Regression analysis showed anode resistance was a limiting factor of the weak MFC and cathode resistance was that of the strong MFCs. This result suggests one operating principle: improve anodes in weak MFCs and cathodes in strong MFCs to achieve better MFC performance. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：We demonstrated the sensing properties and adsorption mechanism of NO2 molecules of monolayer graphene and multilayer graphene encapsulated ZnO QDs for NO2 gas adsorption. The gas response value of ZnO-multilayer graphene (ZMLG) QDs was approximately 23 % and 7.2 and 25.5 times higher than that with ZnO-monolayer graphene (ZG) and ZnO QDs, respectively. The surface potential change of ZMLG QDs increased up to 14.25 times compared to ZnO QDs and 6.33 times increased compared to ZG QDs. We proposed an accurate adsorption mechanism for the improvement of the detection behavior that is occured by covering the graphene shells into ZnO QDs by the Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), and SKPM measurement. These results are expected to increase the accuracy of gas sensor characteristic analysis. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：This work focussed on the fabrication of synergetic spinel CoMn2O4 embedded reduced graphene oxide (CoMn2O4@RGO) nanocomposite over the surface of modified screen-printed carbon electrode (SPCE) for highly sensitive and enhanced electrochemical detection of metol (MTL) in 0.05 M phosphate buffer elec-trolyte. The CoMn2O4@RGO nanocomposite material was synthesized by sonochemical method and well-characterized using various spectral and analytical (XRD, TGA, Raman spectroscopic, FE-SEM, HR-TEM & EA) techniques. Cyclic and differential pulse voltammetry techniques were used for the detection of MTL at CoMn2O4@RGO modified SPCE. The present electrochemical sensor shows a dynamic linear response range from 0.01 to 137.65 mu M and the detection limit, quantification, sensitivity were estimated to be 0.050 mu M, 1.64 mu M, and 3.77 mu A mu M-1 cm(-2). Furthermore, the proposed MTL sensor was exhibited numer-ous advantages including very ease fabrication, high selectivity, stability, and reproducibility for the detection of MTL. Based on the obtained experimental data a plausible MTL redox mechanism was pro-posed. In addition, the present electrochemical sensor was applied in real sample analysis at the spiked samples (lake water samples + MTL) observed with good recovery results. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Polyaniline (PANI), poly(N-methylaniline) (PNMA) and poly(N-formylanilide) (PNFA) coatings were fabricated over mild steel via chronoamperometric strategy in oxalate electrolyte. Scanning electron microscope (SEM), attenuated total reflection infrared spectroscopy (ATR-IR) and X-ray photoelectron spectroscopy (XPS) evidenced the polymerization of monomers. Anticorrosive effects of PANI, PNMA and PNFA coatings for steel substrate were evaluated during long-term immersion in 3.5% NaCl solution by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and frequency modulation (EFM). Morphological variation for coated specimens before and after immersion in NaCl solution was also monitored by SEM and atomic force microscope (AFM). Differentiated protection capability were observed for three coatings following the sequence of PNFA > PNMA > PANI. Through electrochemical and interfacial analyses, electroactivity and physical barrier were ascertained as the critical factors, especially the former one, in the long-term protection capacity. Electroactivity was distinguished by the elevated apparent current density from non-destructive EFM measurements. Furthermore, electron-donation and -withdrawal effects of N-substituents played an essential role in coating electroactivity. In detail, N-substituents improved the anodic protection and physical barrier of PNMA and PNFA coatings. Particularly, formyl with electron-withdrawal effect reinforced the anodic protection and thus the superior the anticorrosion efficiency of PNFA for underlying steel. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：The polarized silver nanoparticles (AgNPs) were used as carriers in CO2 separation through facilitated transport. AgNPs were polarized and stabilized by adding p-benzoquinone (p-BQ). This polymeric composite membrane was used for CO2/N2 separation, and showed high-selective performance. Through CO2 and N2 gas permeation experiment, it was confirmed that these membranes showed ideal selectivity of 117 or more. These separation performances were significantly improved compared to pristine PVP and were due to the selective and reversible interaction between polar CO2 molecules and AgNPs polarized by p-BQ. Positive charged density on surface of particles was analyzed by XPS and it was found that it could accelerate the transport of CO2 molecules through dipole-dipole interaction. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
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