Journal of Physical Chemistry C
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2021
·
IF 4.126
Pengfei Yao,Jing Cao,Xue Gong,Ce Han,Mingbo Ruan,Ping Song,Weilin Xu
The development of catalysts free of platinum-group metals with a high performance for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells is a grand challenge. Herein, we report zeolitic imidazolate framework-8-based Co, N, and S tridoped carbon frameworks (Co–N–S CFs) with high ORR catalytic activity and remarkable durability in an alkaline medium. Results indicate that the high ORR performance of the Co–N–S CFs could be attributed to the unique 3D structure of carbon frames, the synergistic effect among Co, N, and S, and its high electron conductivity. It is also found that the N and S doped heteroatoms can anchor Co atoms by forming CoNx and CoSx active sites for a highly efficient ORR. The results obtained here can help in the design and understanding of the cost-effective highly active Pt-free electrocatalysts.
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高影响因子
MOLECULES
·
2021
·Vol. 26
·期 11
·3108
·
IF 4.412
Mengya Jiao,Qun Dong,Yiting Zhang,Min Lin,Wan Zhou,Tao Liu,Baohong Yuan,Hui Yin
Maca (Lepidium meyenii) has emerged as a popular functional plant food because of its medicinal properties and nutritional value. Macamides, as the exclusively active ingredients found in maca, are a unique series of non-polar, long-chain fatty acidN-benzylamides with multiple bioactivities such as antifatigue characteristics and improving reproductive health. In this study, a new kind of macamide,N-benzyl eicosapentaenamide (NB-EPA), was identified from maca. We further explore its potential neuroprotective role in hypoxic–ischemic brain injury. Our findings indicated that treatment with biosynthesized NB-EPA significantly alleviates the size of cerebral infarction and improves neurobehavioral disorders after hypoxic–ischemic brain damage in neonatal mice. NB-EPA inhibited the apoptosis of neuronal cells after ischemic challenge. NB-EPA improved neuronal cell survival and proliferation through the activation of phosphorylated AKT signaling. Of note, the protective property of NB-EPA against ischemic neuronal damage was dependent on suppression of the p53–PUMA pathway. Taken together, these findings suggest that NB-EPA may represent a new neuroprotectant for newborns with hypoxic–ischemic encephalopathy.Keywords:maca;N-benzyl eicosapentaenamide;neonatal hypoxic–ischemic encephalopathy;neuroprotection;PUMA
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高影响因子
ACS Catalysis
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2021
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IF 13.084
Yiyang Lin,Kang Liu,Kejun Chen,Yan Xu,Hongmei Li,Junhua Hu,Ying-Rui Lu,Ting-Shan Chan,Xiaoqing Qiu,Junwei Fu,Min Liu
Atomically dispersed FeN4 catalysts have been considered as potential materials to replace Pt-based catalysts for the oxygen reduction reaction (ORR), but they often suffer from sluggish O2 activation kinetics due to the symmetrical charge distribution. Herein, we introduce external N, including pyrrolic-N (PN) and graphitic-N (GN), as an electron acceptor near FeN4 to regulate its charge distribution and improve its ORR activity. Theoretical calculations reveal that introduction of PN evokes much enhanced electron redistribution and local electrical field on the Fe site compared with those observed with GN introduction and the pristine one. Synchrotron X-ray absorption spectroscopy and X-ray photoelectron spectroscopy validate the positive charge accumulation of Fe in the FeN4 site induced by introducing PN. Thus, the obtained FeN4-PN exhibits a great performance for ORR in 0.1 M KOH with a remarkable half-wave potential of 0.91 V versus reversible hydrogen electrode, as well as a Tafel slope of 58 mV decade–1. This work provides a guide to improve the catalytic performances of single-atom catalysts by introducing charge-redistribution sites.
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ACS Applied Nano Materials
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2021
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IF 5.097
Jun Zhao,Hanhan Wang,Hongqi Geng,Qi Yang,Yuping Tong,Weiwei He
Disturbances in the redox state of a biological system can cause diverse effects and clinical functions. The key and difficulty lies in controlling the balance between reduction and oxidation. Nanomaterials with oxidoreductase-like activity offer an appealing way to adjust anti- and pro-oxidation in response to biological conditions. To this end, we design and prepare visible light-responsive hybrid nanozymes by combining Au and N-doped carbon dots (Au/NC). It is found that Au/NC can efficiently scavenge reactive oxygen species (ROS) and free radicals and exhibit SOD-like activity, showing intrinsic antioxidant activity. Upon irradiation with visible light, we observe that Au/NC can generate ROS (e.g., hydroxyl radicals, superoxide, and singlet oxygen) and exhibit enhanced oxidase-like activity to accelerate the oxidation of chromogenic substrates, showing pro-oxidant capability. The light-activated oxidative activity is ascribed to the synergistic effects of photoexcitation of N-doped carbon dots and the surface plasmon resonance of Au nanoparticles. In addition, we demonstrate the application of the anti- and pro-oxidant capability of Au/NC in inhibition or acceleration of oxidation of Monascus pigments and Fe2+, which is switched by the incident light. These results will be of significant interest in modulating the biological redox conditions through responsive and precise nanozymes.
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COMBUSTION AND FLAME
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2021
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IF 4.185
Wang Li,Jiu-Zhong Yang,Long Zhao,Dan Yu,Zhen-Yu Tian
With biofuels market expanding, amines, as an important compound class in biofuels, are attracting increasing attention. The pyrolysis of n-propylamine (NPA) was studied in a flow tube using tunable synchrotron photoionization and molecular-beam mass spectrometry techniques. 28 and 30 species, including nitrogenous compounds and hydrocarbons, were identified and quantified at 30 and 760 Torr, respectively. 1,3-Cyclopentadiene, 1,4-pentadiene, 2-methyl-1,3-butadiene and benzene, were newly detected compared with previous studies of methylamine and ethylamine. HCN, NH 3 , N 2 and methanimine were detected as the dominant nitrogenous products. Moreover, minor aliphatic and unsaturated amines were also identified, such as methylamine, ethylamine and acetaldimine. Ethylene achieved at the highest level among hydrocarbon products. With the pressure increasing, the onset temperature of NPA pyrolysis shifts towards low temperature region and NPA decomposes faster. A comprehensive detailed kinetic model involving 405 species and 2668 reactions was developed with reasonable predictions. According to rate-of-production analysis, H-abstractions, especially at C α position of NPA, are the major consumption pathways of NPA. In addition, unimolecular reaction breaking C α -C β bond is the important consumption channel of NPA at 30 Torr, while its positive effect is seriously weakened at 760 Torr. The H-abstraction at C α (NPA+ H CH 3 CH 2 CHNH 2 +H 2 ) plays a leading role for NPA consumption at 760 Torr. The reactions, CH 3 +CH 3 =C 2 H 5 + H and CH 3 CHCHNH 2 + H CH 2 CHCHNH 2 +H 2 , tend to present inhibiting effects on NPA consumption at 30 and 760 Torr, respectively. These results could provide a theoretical basis for further combustion kinetic studies of biofuels and amine fuels.
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ADVANCED ENGINEERING MATERIALS
·
2021
·Vol. 23
·期 5
·2001252
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IF 3.862
Dawei Zheng,Tianwei Huang,Bing Xu,Xu Zhou,Yaofeng Mao,Lin Zhong,Bing Gao,Dunju Wang
The development of 3D printing technology provides a new idea for the application of energy-containing materials as functional reactive materials, which helps Al–F high-energy materials to achieve customized performance and structure, so that energy transmit can be targeted. A high fuel-load ink (up to 90 wt%) based on Al-polytetrafluoroethylene (PTFE) is designed and fabricated using fluororubber (FR) as a binder. The content of FR is directly related to the mechanical properties of ink, and the customized structure from the uniform and stable deposition can be obtained by adjusting the content of FR (10–20 wt%). Under the display of high-speed photography, the ink shows a strong stability in combustion performance, which is conducive to realize the performance customization of the ink in the application. To better understand the combustion mechanism, the thermal properties and combustion process are analyzed in brief through thermal analysis and the combustion snapshots.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2021
·
IF 5.816
Chunyu Zhang,Guozhu Liu,Bo Ning,Shuairen Qian,Danning Zheng,Li Wang
The electrochemical oxygen reduction reaction (ORR) via two-electron pathway is a sustainable way of producing hydrogen peroxide. Nanostructured carbon materials are proved to be effective catalysts for 2e − ORR. Herein, a series of mesoporous carbon with tunable nitrogen species and oxygen functional groups were synthesized by varying the added amount of dopamine hydrochloride as nitrogen and oxygen source. The modified catalysts exhibited higher content of pyrrolic-N and ether C–O groups which are confirmed by a series of characterization. Raman spectra and correlation analysis revealed that the increased proportion of defect sites in carbon materials are closely related to the introduced pyrrolic-N and ether C–O groups. And the rotating ring-disk electrode (RRDE) measurement carried out in 0.1 M KOH electrolyte showed the H 2 O 2 selectivity increased with the content of defect sites. Among them, the optimized catalyst (NOC-6M) exhibited a selectivity of 95.2% and a potential of 0.71 V vs. RHE at −1 mA cm −2 . Moreover, NOC-6M possessed the high H 2 O 2 production rate of 548.8 mmol g cat −1 h −1 with faradaic efficiency of 92.4% in a two-chamber H-cell. Further mechanistic analysis revealed that the introduction of pyrrolic-N and ether C–O are likely to improve the binding energy of the defect sites toward ∗OOH intermediate, resulting in a more favorable 2e − ORR pathway for H 2 O 2 production.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2020
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IF 3.905
Shuang Zong,Yue Zhang,Morena S. Xaba,Xinying Liu,Aibing Chen
N-doped porous carbon nanotubes (NCNs-A) were successfully prepared by a scalable and straightforward mixed salts (NaCl/ZnCl 2 ) activation method with carbon precursor of polypyrrole (PPy). The independent salt NaCl or ZnCl 2 , the dosage of mixed salts, and the carbonization temperature all have a strong effect on the final products. ZnCl 2 is the key activator for activation, and with an increase of the mixed salts, the surface area of NCNs-A is increased. However, excess salt can lead to a decrease in the surface area. Additionally, a suitable carbonization temperature also increases the surface area. The results indicate that optimal synthesis conditions are a mixed salts mass ratio of 2 and a carbonization temperature at 800℃. During the carbonization process, the mixed salts as combined porogen and template ensure the obtained NCNs-A possesses tubular morphology derived from PPy, abundant porous architecture, a high specific surface area of 1278 m 2 g −1 and a high nitrogen doping of 9.26 at%. When used as electrode material for the supercapacitor, the NCNs-A achieved an outstanding electrochemical performance.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
·
IF 4.65
Jianfei Xiao,Yuan Wang,Tian C. Zhang,Shaojun Yuan
A novel porous carbon derived from glucose and dicyandiamide incorporated with reduced graphene oxide (rGO) was prepared for CO 2 capture and supercapacitors . In this synthesis, one-pot hydrothermal and KOH activation were employed to obtain reducing graphene oxide/N-doped porous carbon (rGO/NPC) composites. Among the rGO/NPC composites derived, the sorbent rGO/NPC-600-2-1 (1 represents the addition amount of graphene oxide is 1% of the total mass of glucose and dicyandiamide, 2 represents the mass ratio of potassium hydroxide to the precursor of carbon composite material is 2 and 600 means activation temperature is 600 °C) had a large surface area of 865.1 m 2 g −1 , a rich nitrogen doping amount of 7.07 wt%, and a high CO 2 capture ability of 5.77 mmol/g at 298 K. Additionally, the as-synthesized rGO/NPC-600-2-1 was used as a supercapacitor electrode, providing a specific capacitance 210.8 F g −1 in 6 M KOH electrolyte under ambient conditions and excellent charge and discharge long cycle stability (circa 100% capacitance retention at a current density of 10 A g −1 after 10000 cycles). Even at a high current density of 20 A g −1 , a capacity of 141.1 F g -1 is still maintained. The results above suggested that the rGO/NPC composites are applicable candidates for both electrochemical energy storage and CO 2 capture.
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高影响因子
FOOD CHEMISTRY
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2020
·
IF 6.306
Yu Lu,Cheng Li,Jie Liu,Wenqi Huang,Yuerong Yang,Yue Jia,Tingting Liu,Linjuan Huang,Zhongfu Wang
Goat milk oligosaccharides represent an unexplored multi-functional ingredient for the dairy industry. Here, we qualitatively and quantitatively compared the N/O -glycome at different lactation stages via online hydrophilic interaction chromatography-tandem mass spectrometry. Complex N -glycans and high mannose N -glycans constituted 82.1% and 17.9% of the glycan pool, respectively. N -glycans with isomers containing non-bisected antenna complex structures accounted for 30.8%. N -glycans modified with Neu5Ac, Neu5Gc and fucosylated were 3.7%, 5.3% and 35.3%. The triantennary trifucosylated complex N -glycan (H5N5F3) was reported for the first time. A comparison between colostrum and mature milk revealed a 1.20-fold decrease in total N -glycans and 1.66-fold decrease in fucosylation with ongoing lactation, echoing the trend in human milk. Similarly, Neu5Ac- and Neu5Gc-modified sialylation decreased by 1.69 and 3.62 times, respectively. In the O -glycome, 46.2% of structures were O -linked core 1, 23.1% were O -linked core 2, 7.7% were O -linked core 3 and core 4. As lactation progressed, overall O -glycans content decreased by 1.26-fold. Unlike human milk, Neu5Ac- and Neu5Gc-modified sialylation increased by 4.4 and 2 times, respectively. These findings will facilitate research on the structure-function relationship of goat milk oligosaccharides and the development of formula food targeting different age groups.
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高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Linjuan Wang,Siva Krishna Karuturi,Ling Zan
We present one-pot hydrothemal syntheis of SnS 2 -In 2 S 3 p-n heterostructures for photocatalytic reduction of Cr 6+ to Cr 3+ . The conduction bands of In 2 S 3 and SnS 2 serve as the photogenerated electron donors and acceptors, respectively, forming a p-n junction band alignment improving the photogenerated charge separation efficiency. Through a detailed investigation of photocurrent spectra, photoluminescence spectra and electrochemical impedance, the heterojunction formation is shown to enhance the photogenerated charge separation and transport properties. In addition, the analysis of 5,5-Dimethyl-1-pyrroline N-oxide (DMPO) spin trapping electron spin resonance (ESR) spectra and band structure further testify the p-n junction of the composite catalyst that could accelerate the electron transport and change the pathway of photocatalytic process toward Cr 6+ reduction. Furthermore, SnS 2 -In 2 S 3 heterojunction photocatalyst achieved 3 times and 67 times higher efficiency than pure In 2 S 3 and SnS 2 photocatalysts under visible light toward Cr 6+ reduction. Moreover, the SnS 2 -In 2 S 3 p-n heterojunction photocatalyst demonstrates Cr 6+ removal in a weak alkaline solution, breaking through the challenge of Cr 6+ reduction in an alkaline environment.
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Canadian Journal of Chemistry
·
2020
·Vol. 99
·期 3
·
IF 1.171
Jianfa Chen,Tianxiang Jin,Hangchun Deng,Jie Huang,Guangyuan Ren,Yong Qian
In this work, MoO2@NPGA nanocomposites were successfully prepared via a simple hydrothermal and calcination route. The as-prepared MoO2@NPGA composites exhibit a synergistic effect between MoO2 and N,P-codoped graphene aerogels, which can significantly improve the electrochemical performance of the MoO2@NPGA electrodes. Moreover, the results also proved that the mass loading of MoO2 has a huge effect on the electrochemical properties of MoO2@NPGA composites. With an appropriate amount of MoO2, the MoO2@NPGA composite shows a high specific capacitance (335 F g−1 at 1 A g−1) and excellent cycle stability (capacitance remains at 88% after 6000 cycles). Furthermore, the assembled symmetric supercapacitor displays a high energy density of 23.75 W h kg−1 at a power density of 300 W kg−1 and can maintain an energy density of 17.1 W h kg−1 when the power density reaches up to 6005 W kg−1.
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