Catalysis Science & Technology
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2020
·Vol. 10
·期 15
·5298-5305
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IF 5.721
Xuanxuan Yang,Yu Guo,Yongbing Lou,Jinxi Chen
Rational design of highly efficient photocatalysts based on molybdenum cocatalysts is prospective to achieve hydrogen evolution under visible light. Herein, Mn0.5Cd0.5S nanoparticles decorated with O-doped MoS2 nanosheets (denoted as O-MoS2/Mn0.5Cd0.5S) were successfully synthesized. The incorporation of O atoms, which could trigger defects and enlarge the interlayer distance of MoS2, was achieved by a simple hydrothermal method. The performances of O-MoS2/Mn0.5Cd0.5S composites for catalyzing hydrogen evolution are rapidly enhanced with increasing contents of O-MoS2. The resultant 12 wt% O-MoS2/Mn0.5Cd0.5S composite exhibits superior stability and a satisfactory hydrogen production rate up to 84.32 mmol g−1 h−1 and the apparent quantum efficiency at 420 nm is 46.92%, which is 3.18 times higher than that of Mn0.5Cd0.5S nanoparticles. To the best of our understanding, such an exceptional activity of 12 wt% O-MoS2/Mn0.5Cd0.5S prepared in this work for hydrogen evolution is one of the highest among all reported Mn–Cd–S-based catalysts. The markedly strengthened activity is attributed to the improved light absorption and effective separation of photoinduced carriers between O-MoS2 nanosheets and Mn0.5Cd0.5S nanoparticles. This work indicates that O-MoS2 is a potential cocatalyst for the rational construction of efficient photocatalysts.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
·
IF 5.162
Lei Wang,Yujie Li,Dong Xiang,Weimin Zhang,Xinpeng Bai
Lutein is a hydrophobic carotenoid with diverse bioactivities. For encapsulating the molecule in a novel method, we prepared two emulsions from xanthan and propylene glycol alginate at the ratios of 3:7 and 4:6. The instability index and particle size of the emulsions were determined using a stability analyzer and laser particle size analyzer. The influence of crystallization on the emulsions was observed under a polarizing microscope. The effects of centrifugal force and storage on the lutein emulsions were analyzed by measuring the changes in absorbance. The results showed that the emulsion fabricated by xanthan and propylene glycol alginate at the ratio of 4:6 was highly stable, and crystals were dispersed when xanthan and propylene glycol alginate existed. These results revealed that the hydrophobicity and absorption kinetics of emulsifiers would determine the stability of emulsion when the viscosity of emulsifiers reached a certain value, and the stability of emulsions would affect the stability of lutein in the emulsions.
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Nuclear Materials and Energy
·
2020
·
IF 2.213
Xinyi Yang,Liangliang Song,Bo Chang,Qi Yang,Xiaodong Mao,Qunying Huang
The low solubility of gadolinium (Gd) limits its application in iron-based neutron shielding alloys. In this study, a high content of Gd up to 7.87 wt.% was added into 316L stainless steel by mechanical alloying (MA) of Gd 2 O 3 with 316L powder. Neutronics calculation results showed that the shielding efficiency of 0.2 mm thick 7.87 wt.% Gd-316L alloy was equivalent to that of 33 mm thick 316L for thermal neutrons. Microstructure analysis indicated that Gd-Si-O particles with an average size of 12.5 nm were uniformly dispersed in the matrix. It revealed that Gd 2 O 3 dissolved into the 316L matrix during MA and re-precipitated at around 780 °C as Gd 2 SiO 5 by XRD and TG-DSC. This study provides a novel Gd-containing alloy designed to achieve integration of structural alloys with good neutron shielding function for future application.
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TALANTA
·
2020
·
IF 5.339
Xue Han,Zhen Meng,Lian Xia,Fengli Qu,Rong-Mei Kong
This study demonstrates a novel and convenient ratiometric fluorescent method for the detection of alkaline phosphatase (ALP) activity. Amino-functionalized mesoporous silica nanoparticle-gold nanoclusters (MSN-AuNCs) nanocomposites were integrated with o-phenylenediamine (OPD) to form a ratiometric fluorescence nanoplatform. The presence of ALP induced the generation of quinoxaline (QX) derivative which called 3-(dihydroxyethyl)furo[3,4-b]quinoxaline-1-one (DFQ) with strong fluorescence emission at 450 nm, while the orange-red fluorescence of MSN-AuNCs at 580 nm was slightly quenched. Meanwhile, an obvious fluorescence color change from orange-red to purple and finally to blue can be observed by naked eyes with the increasing of ALP concentration. Therefore, employing the fluorescence emission of DFQ at 450 nm as the reporter signal and the fluorescence emission of MSN-AuNCs at 580 nm as a reference signal, a sensitive ratiometric detection method for ALP was developed. Quantitative detection of ALP activity in the linear range from 0.2 to 80 U/L with a detection limit of 0.1 U/L can be realized in this way, which endows the assay with high sensitivity enough for practical detection of ALP in human serum samples.
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2020
·Vol. 24
·期 3
·633-640
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IF 2.646
Liu Bingqian,Shi Weiping,Yang Yani,Cai Jie
In this paper, a simple and feasible immunoassay protocol with signal amplification for sensitive determination of alpha fetoprotein (AFP, used as a model) by using new enzyme-induced Fenton reaction (EIFR) accompanying the oxidation of o-phenylenediamine (OPD) system. We discovered that glucose oxidase (GOx) has the ability to stimulate in situ Fenton reaction coupling the oxidation of OPD. GOx-catalyze of glucose results in the formation of hydrogen peroxide (H 2 O 2 ). It can catalytically oxidize Fe 2+ to Fe 3+ , meanwhile producing hydroxyl radicals (•OH). The latter effectively initiated the catalytic oxidation of o-phenylenediamine (OPD) to 2,2-aminoazobenzene (DAP), resulting in the production of an electrochemical signal. On the basis of EIFR-OPD system, a new immunoassay protocol with GOx/anti-pAb 2 -conjugated gold nanoparticle (Ab 2 -AuNP-GOx) detection antibody can be designed for the detection of target AFP on capture antibody–functionalized transparent 96-well polystyrene microplate, monitored by recording the current peak of the generated DAP. The electrochemical current shows to be positively correlated with the concentration of target AFP. Under optimal conditions, the proposed assay exhibited good electrochemical responses for detecting target AFP in the range of 1.0 pg mL − 1 to 100 ng mL −1 with a detection limit (LOD) of 0.5 pg mL −1 (0.5 ppt) estimated at the 3 S blank level. Additionally, the precision, reproducibility, specificity, and method accuracy were also investigated with acceptable results. Importantly, the EIFR-OPD system can be further extended for the determination of other protein or biomarkers by controlling the specific recognition system (antibody or aptamer).
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POLYMER
·
2021
·
IF 4.43
Xiaotao Wang,Yebin Yang,Chuang Liu,Huiling Guo,Zhuofan Chen,Junyong Xia,Yonggui Liao,Chak-Yin Tang,Wing-Cheung Law
A near infrared (NIR) and pH dual-responsive nanocomposite, composed of a lanthanide-doped upconversion nanoparticle (UCNP) core and a transformable poly- o -nitrobenzyl shell, was prepared by the distillation precipitation polymerization and template method. The poly- o -nitrobenzyl shell can undergo hydrophobic-hydrophilic transformation upon an irradiation of 980 nm, rendering the capability of NIR-activated drug release. The anticancer drug , doxorubicin (DOX), can be loaded into these nanocomposites with a loading efficiency of 7.23 wt%. Furthermore, pH responsiveness caused by the hydrogen bond and charge interactions between DOX and nanocapsules can trigger the release of drugs at low pH. Under visible light irradiation and neutral (pH 7.4) conditions, the cumulative release of DOX was only 8.35% after 300 min, while it reached 59.5% under the synergistic effect of NIR irradiation and acidic conditions. The Baker-Lonsdale model was used to describe the drug release kinetics of this system, and the diffusion coefficient (3 DC s / r 0 2 C 0 ) and R 2 under different conditions were determined to be 4.15 × 10 −6 and 0.98 (pH 7.4 and visible light), 2.64 × 10 −5 and 0.99 (NIR light), 3.26 × 10 −5 and 0.97 (pH 4.5 and visible light), 2.59 × 10 −4 and 0.99 (pH 4.5 and NIR light), respectively. This controlled release feature makes the nanocomposite a promising therapeutic agent for treating diseases.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Shuaiqi Zhao,Peng Wu,Jiajin Lin,Yifei Li,Anqi Li,Xiaojing Jin,Yu Chen,Bote Zhao,Yun Zhao,Guangxu Chen,Yongcai Qiu,Daiqi Ye,Shihe Yang
The development of low-temperature and water-resistant heterogeneous catalysts without noble metals is vital in the effective treatment of atmospheric pollutants in practical application. Herein, we report that Cu(I)-O-Co interfaces of ultrafine CuO x on Co 3 O 4 prepared by co-precipitation exhibit promising low-temperature activity and good water resistance. Experiment results together with density functional theory (DFT) calculations not only verify that Cu + species are stabilized over Cu(I)-O-Co interfaces because of the strong interaction between Cu 2 O 1 and Co 3 O 4 , but also demonstrate that the Cu(I)-O-Co interface facilitates oxygen species activation for promoting catalytic oxidation and reduces the accumulation of hydroxyl and bicarbonate species on the surface of CuO x /Co 3 O 4 . DFT calculations also reveal that the CO oxidation rate-limiting step via the dissociation pathway under dry conditions is the Co-OO-Cu species dissociation while the CO coupling with the adsorbed O 2 becomes the rate determining step for CO oxidation through the direct pathway over Cu(I)-O-Co interface under humid conditions. Further, the CuO x /Co 3 O 4 catalyst also exhibits superior and stable catalytic activity for toluene oxidation, comparable with partial supported noble metal catalysts (T 90 = 190 °C). The present work gives a useful strategy for the rational design of low-temperature and water-resistant non-precious-based catalysts to be applicable in CO and toluene removal in practical applications.
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LIFE SCIENCES
·
2019
·
IF 3.448
Enxia Zhang,Jiasi Liu,Lei Shi,Xin Guo,Ze Liang,Jiaxin Zuo,Hong Xu,Huaxin Wang,Xiaohong Shu,Shanshan Huang,Shubiao Zhang,Xiaohui Kang,Yuhong Zhen
Aims To investigate the effect of 7- O -geranylquercetin (GQ), a derivative of quercetin (Q), on reversing drug resistance in breast cancer MCF-7/ADR cells and reveal the mechanisms related to P-glycoprotein (P-gp). Main methods Cell viability was determined by MTT assay. Accumulation of adriamycin (ADR) in cells was determined by confocal fluorescence microscope and microplate reader while that of rhodamine (Rh) was measured by flow cytometry. Expression levels of P-gp and MDR1 gene in cells were detected by western blot and Real-Time PCR, respectively. Molecular docking of GQ and Q with P-gp was conducted using AutoDock program. Xenograft model was established by inoculating MCF-7/ADR cells in BALB/c-nude mice. Tumor bearing mice were administered with ADR via tail vein injection and/or GQ (Q) by gavage. Expression levels of P-gp in tissues were detected by western blot and immunohistochemistry. Key findings GQ could reverse drug resistance of MCF-7/ADR cells to ADR. GQ inhibited the efflux of ADR by down-regulating the expression of P-gp protein and its encoding gene MDR1 in MCF-7/ADR cells. Molecular modeling showed that GQ matched with P-gp better than Q. GQ enhanced the antitumor effects of ADR and decreased the expression of P-gp in mice and its activities were higher than that of Q. GQ could reverse drug resistance of MCF-7/ADR cells by down-regulating the expression of P-gp in vitro and in vivo. Significances The reversal effect of GQ on P-gp-mediated drug resistance indicates its potential as a reversal agent for drug resistance in cancer chemotherapy.
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Results in Physics
·
2019
·
IF 3.042
Yang Zhou,Xiaoyuan Liu,Ke Wang,Jing Li,Xinglai Zhang,Xin Jin,Xinyue Tang,Xiuhui Zhu,Ruishi Zhang,Xin Jiang,Baodan Liu
Series of “Hopcalite” catalysts for low-temperature CO oxidation are prepared through a facile ultra-sonic spray pyrolysis approach. It has been found that the spray pyrolysis temperature and Cu/Mn atomic ratio in initial precursors show significant impacts on the catalytic activity of Cu-Mn-O catalysts. The catalyst synthesized at 550 °C with Cu/Mn = 1/2 in precursor (Cu1Mn2-550) shows the highest catalytic activity towards CO oxidation (T 100 = 63 °C; E a = 17.04 KJ mol −1 ), owing to the formation of CuMn 2 O 4 phase with poor crystallinity. The synergistic effect of Cu and Mn species in spinel Cu-Mn-O phases attributes to the evaluated catalytic activity compared with those of pure oxides of copper or manganese towards CO oxidation. The results reveal that Cu1Mn2-550 not only provides more defects and vacancies to create more active sites, but also generates more highly active Cu (II) to promote CO oxidation. On the contrary, the decreasing amount of Cu (II) and the higher degree of crystallinity resulting from higher synthesis temperature lead to the deterioration of catalytic activity. Moreover, the phase transformation among the Cu x Mn 3-x O 4 spinels also shows significant effect on CO conversion rate. Finally, the formation mechanism of Cu-Mn-O catalysts and related CO oxidation process are discussed based on series of characterizations.
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Materials Research Express
·
2019
·Vol. 6
·期 9
·095601
·
IF 1.449
Hao Xu,Xiang-Hui Yan,Ziwei Meng,Tong Xue,Dong Li,Guoli Fang,Hongfang Shen
Nitrogen-doped mesoporous carbon/poly-o-phenylenediamine composites (denoted as N-MC/PoPD) were successfully synthesized by sacrificial hard template method followed by in situ oxidation polymerization initiated by FeCl3. It is revealed that the resultant N-MC/PoPD composites still remained original graphitization structure and narrow pore size distributions (centered at ∼3.8 nm) but suffered visibly monotonical decrease in specific surface area after oPD was increasingly polymerized onto N-MC with an increase of the mass ratio of PoPD to N-MC from 1:1 to 5:1. As supercapacitor electrode measured by galvanostatic charge-discharge in 6 mol L−1 KOH, a volcano curve was found when plotting specific capacitance of the N-MC/PoPD versus the mass ratio of N-MC to oPD; the N-MC/PoPD(2:1) with moderate surface area and the highest electrochemical conductivity delivered the highest specific capacitance of 229 F g−1 at a current density of 1 A g−1, which is twice of that obtained on the single N-MC with the maximum surface area. The remarkable enhancement in specific capacitance could be ascribed to the synergistic effect between two components of N-MC and PoPD.
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ACS Nano
·
2019
·
IF 13.903
Hao Ren,Xiaoli Sun,Chengfeng Du,Jin Zhao,Daobin Liu,Wei Fang,Sonal Kumar,Rodney Chua,Shize Meng,Pinit Kidkhunthod,Li Song,Shuiqing Li,Srinivasan Madhavi,Qingyu Yan
Electrocatalysts are one of the most important parts for oxygen evolution reaction (OER) to overcome the sluggish kinetics. Herein, amorphous Fe–Ni–P–B–O (FNPBO) nanocages as efficient OER catalysts are synthesized by a simple low-cost and scalable method at room temperature. The samples are chemically stable, in clear contrast to reported unstable or even pyrophoric boride samples. The Fe/Ni ratio of the FNPBO nanocages can be continuously adjusted to optimize the OER catalytic performance. The FNPBO nanocages composed of multicomponent elements can weaken the metal–metal bonds, thus rearranging the electron density around the catalytic metal atom centers and reducing the energy barrier for intermediate formation. Hence the optimized FNPBO (Fe6.4Ni16.1P12.9B4.3O60.2) catalyst shows superior intrinsic electrocatalytic activity for OER. The low overpotential to afford the current density of 10 mA cm–2 (236 mV), the small Tafel slope (39 mV dec–1), and the high specific current density (26.44 mA cm–2) at a given overpotential of 300 mV make a sharp contrast to state-of-the-art RuO2 (327 mV, 136 mV dec–1, and 0.028 mA cm–2, respectively).
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Ji Ying Long,Zhi Shuo Yan,Yun Gong,Jian Hua Lin
Based on a meta-organic framework (MOF) formulated as [Co 4 (phen) 4 Cl 8 ] (phen = 1, 10-phenanthroline) as precursor, Cl/O doped C/CoO material (C/CoO-200) was synthesized by a one-step calcining method at a low temperature of 200 °C. In C/CoO-200, CoO nanoparticles with an average size of 25 nm were linked by carbon matrix into particles with the diameter of 200 nm ∼ 1 μm. The sample possessed a very low atomic percentage of CoO (CoO: 1.9%; C: 86.8%) due to the large amount of carbon from the organic ligand, phen in the precursor. However, it still exhibited a large specific capacitance of 1052 F g −1 at 0.5 A g −1 in 2 M KOH electrolyte with a 79.6% capacitance retention at 10 A g −1 . After successive etched in acid, Cl/O doped carbon nanoparticles were obtained. C-300 was composed by individual nanoparticles with size of 100–500 nm, it showed a specific capacitance of 207 and 164 F g −1 in 2 M KOH at a current density of 0.5 and 1 A g −1 , respectively, which was comparable to the commercial activated carbon (AC) (199 and 179 F g −1 for AC at 0.5 and 1 A g −1 , respectively). An asymmetric supercapacitor based on the positive electrode of C/CoO-200 and the negative electrode of C-300 exhibited a stable performance with a 61% retention of specific capacitance after 10,000 charging-discharging cycles at 1.5 A g −1 .
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