RSC Advances
·
2015
·Vol. 5
·期 77
·63044-63049
·
IF 3.84
Hualei Hu,Jinghui Lyu,Jie Cen,Qunfeng Zhang,Qingtao Wang,Wenwen Han,Jiayao Rui,Xiaonian Li
The effect of MgO and Pd modification on the catalytic performance of hierarchical porous ZSM-5 for benzene alkylation with methanol was investigated. The results indicated that the introduction of MgO could reduce the Brönsted acid sites which suppressed the side reaction of methanol to olefins and in turn effectively promoted the alkylation of benzene. However, the single modification of MgO could not completely suppress the formation of ethylbenzene and coke. Doping a small amount of Pd had a positive effect on inhibiting the generation of ethylbenzene and coke, which could be attributed to the hydrogenation of ethylene into ethane on Pd. The dual modified catalyst (MgO and Pd) exhibited high benzene conversion (56%) and xylene selectivity (39.1%), and the lowest ethylbenzene selectivity (0.13%) and coke content (0.4 wt%).
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Jiamin Huang,Guanghui Zhang,Jie Zhu,Mingrui Wang,Fanshu Ding,Chunshan Song,Xinwen Guo
The catalytic conversion of CO2 to higher alcohols (HAs, representing ethanol and alcohols with more than two carbon atoms) has been of great interest to mitigating the greenhouse effect and effectively utilizing CO2. However, most present catalysts have disadvantages of poor activity (conversion less than 30%) and selectivity (less than 10%) and high price. Herein, we report a Mn- and K-modified iron carbide catalyst that offers a CO2 conversion higher than 40% and a selectivity of higher alcohols exceeding 10%, and the proportion of propanol and butanol in alcohol products is more than 30%. Unpromoted iron carbide has a strong ability of hydrocarbon chain growth, leading to the fast formation of hydrocarbon products rather than HAs. However, on the Mn- and K-modified iron carbide catalyst, K is used to increase the surface C/H ratio of the catalyst by enhancing the adsorption of CO2 on the catalytic surface. The increased C/H ratio is indispensable to the formation of HAs, and the addition of Mn promoter dramatically improves the production of HAs, especially the formation of propanol and butanol. The synergistic effect between Mn and K on iron carbide is the key to produce HAs. In addition, the Mn- and K-modified iron carbide is of low cost, which can potentially provide an alternative for the hydrogenation of CO2 to produce valuable chemicals.
研究领域:
催化化学
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环境科学
·
能源科学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2024
·
IF 3.5
Zihao Hu,Xiaoying Zhou,Tiantian Zhang,Zuliang Wu,Jing Li,Wei Wang,Erhao Gao,Jiali Zhu,Shuiliang Yao
Aiming at the problem of the poor performance of an Mn-MOF-74-derived Mn3O4 catalyst in low-temperature carbon monoxide (CO) oxidation, copper (Cu) and cerium (Ce) elements were used to modify the Mn3O4 catalyst to improve its performance in low-temperature CO oxidation. According to the results of catalytic performance testing, the CO oxidation activity of the Cu0.3Mn2.7O4 catalyst was significantly improved compared with that of the pristine Mn3O4 catalyst, when a CO conversion rate of 90% was achieved at 118 °C. According to X-ray photoelectron spectroscopy and Brunauer–Emmett–Teller analyses, the (Mn2+ + Mn3+)/(Mn2+ + Mn3+ + Mn4+) ratio and the Oads/Ototal ratio increased after Cu doping, indicating promoted oxygen vacancy generation. In addition, the increased specific surface area was beneficial for the adsorption of reactant molecules and the exposure of active sites. According to H2-temperature-programmed reduction characterization, Cu doping significantly enhanced the performance of the Cu0.3Mn2.7O4 catalyst during low-temperature redox. Finally, these factors synergistically promoted the degradation of CO over the Cu0.3Mn2.7O4 catalyst. In addition, operando diffuse reflectance Fourier transform infrared spectroscopy results suggested the presence of more terminal-type oxygen, which is essential for the catalytic oxidation of CO on the surface of the Cu0.3Mn2.7O4 catalyst. Moreover, the Cu0.3Mn2.7O4 catalyst also showed excellent resistance to carbonate, and remarkable stability.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROCESS BIOCHEMISTRY
·
2022
·
IF 4.885
Yaling He,Hui Chen,Ziyang Ye,Xinmiao Zhang,Hongling Ye,Ming Ye
To prepare zinc and selenium modified polysaccharides derivatives (ZnLEP-1a and SeLEP-1a), a novel polysaccharide (LEP-1a) isolated from Lachnum YM38 was chosen. Following that, the structural characterization and in vitro bioactivities of LEP-1, ZnLEP-1a and SeLEP-1a were investigated. Results revealed that LEP-1a had a molecular weight of 5.69 × 10 4 Da and was composed of mannose , galactose and glucose. The linkage types of LEP-1a were proved to be (1→)-α- D -Manp, (1→3)-α- D -Manp, (1→2)-α- D -Galp, (1→2)-α- D -Glcp, (1→2,6)-α- D -Manp. Zinc content of ZnLEP-1a was 0.69 mg/g, while selenium content of SeLEP-1a was 206.99 µg/g. Compared with LEP-1a, ZnLEP-1a and SeLEP-1a had a lower molecular weight, same monosaccharides in different molar ratios. The results of FT-IR, DSC , NMR, SEM and AFM suggested that there were obvious changes in structural characteristics after LEP-1a was modified with zinc and selenium. ZnLEP-1a and SeLEP-1a had stronger antioxidant, hypoglycemic, antitumor activities in vitro in comparison with LEP-1a. As a result, ZnLEP-1a and SeLEP-1a showed great potential to develop into a natural antioxidant, hypoglycemic and low-toxic antitumor drug.
研究领域:
生物化学
·
药理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF FOOD ENGINEERING
·
2024
·
IF 5.3
Jingye Zhu,Suping Zhu,Jianshe Chen,Yong Chen
Emulsions stabilized by normal starch-based emulsifier could be easily digested for fat absorption. In this study, a novel design of resistant starch-based emulsifier (RSE) is expected to be a promising strategy in reducing fat digestibility . Waxy corn starch (WCS) was used to prepare RS by pullulanase debranching, and then RS was esterified with different hydrophobic agents of octenyl succinic anhydride (OSA) and dodecenyl succinate anhydride (DDSA) to prepare OSA/DDAS modified RSE (OSA-R and DDSA-R). The structure and emulsification properties of OSA-R and DDSA-R were comprehensively investigated. The results showed that RS content of WCS was increased from 0.17% to 35.52% by pullulanase debranching and then RS contents of OSA-R (37.53%) and DDSA-R (42.18%) could be further increased by OSA/DDSA modifications. Moreover, both OSA-R and DDSA-R stabilized emulsions were stable under neutral and alkaline conditions and were of good quality within 10 days of storage at 4 °C. Compared with OSA-R stabilized emulsion, DDSA-R stabilized emulsion had higher acid stability, CaCl 2 stability and storage stability. Furthermore, in vitro digestion study demonstrated that both OSA-R and DDSA-R stabilized emulsions exhibited strong resistance against digestion. In conclusion, two high resistant starch-based emulsifiers obtained by OSA/DDAS modifications could be used for stabilizing oil-in-water emulsions, which provide important references for the selection of RSE esterification agents and the application of RS in food industry.
研究领域:
食品科学
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生物化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 42
·24056-24063
·
IF 12.732
Yanfang Chen,Xuemei Yan,Jixiang Xu,Lei Wang
H2O2 has a wide range of uses as an oxidant and is also utilized as a high density and environmentally friendly fuel. In this study, crystalline g-C3N4 was modified with K+, Ni and N-doped carbon by thermal-polymerization of Ni2+-anchored and polyvinyl pyrrolidone-encapsulated melamine-cyanuric acid supramolecules, followed by re-calcination in a KCl–LiCl mixture. The obtained strip-like g-C3N4 nanocrystals exhibited high charge separation efficiency and good light absorption capability. Density-functional theory calculations confirmed that the orbital hybridization of Ni–N atoms enabled the formation of charge-transfer channels, which can capture electrons, achieve enhanced oxygen adsorption and reduction via a two-electron pathway. Under the synergistic effects of K+, Ni and N-doped carbon dopants and crystallinity, the obtained sample exhibited high photocatalytic H2O2 yields of 79.6 μM in O2-saturated pure water, which was 10-fold higher than the yield using pristine g-C3N4. This work provides a novel design for production of highly efficient photocatalysts for H2O2 production.
研究领域:
材料科学
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环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 14
·9354-9363
·
IF 12.732
Zheng Si,Baozhao Shi,Jin Huang,Ye Yu,You Han,Jinli Zhang,Wei Li
Nickel-rich layered oxides (LiNixCoyMn1−x−yO2) (x ≥ 0.8, NCM) are intensively developed cathode materials for lithium-ion batteries owing to their high energy and low price, however, their application is impeded by poor cycle stability. Herein we explored a Ti and F co-doped Li(Ni0.8Co0.1Mn0.1)O2 cathode through a solid phase reaction using the precursors of TiO2 and NH4F. Combining the characterization results of XRD, Ar sputtering assisted XPS, HRTEM, in situ XRD, etc, it is illustrated that Ti4+ and F− co-modification can synergistically modulate the lattice parameter and the Ni2+/Li+ mixing degree for the Li(Ni0.8Co0.1Mn0.1)O2 cathode material. Particularly, density functional theory (DFT) calculations demonstrate that Ti and F co-doping is beneficial to form stable crystal structures with a layered phase and rock-salt phase. Ti4+ and F− co-dopants induce the formation of an ultra-thin rock-salt phase on the cathode surface, which provides a protective layer on the nickel-rich cathode surface, so as to enhance the electrochemical performance. The optimal Ti4+ and F− co-doped sample 0.5Ti@0.5F-NCM shows a superior discharge capacity of 202.2 mA h g−1 at 1C and 45 °C, and a capacity retention of 88.1% after 200 cycles, much higher than the retention of 45.2% for NCM. For 0.5Ti@0.5F-NCM, the lithium-ion diffusion coefficients after the 1st and 100th cycles are 2.67 × 10−11 cm2 s−1 and 7.14 × 10−12 cm2 s−1 respectively, larger than those of the pristine NCM (1.37 × 10−11 cm2 s−1 and 4.52 × 10−12 cm2 s−1). The Ti4+ and F− co-doping can suppress the H2–H3 phase change of the cathode during the charge and discharge process and reduce the charge transfer resistance. The results provide a simple and feasible design strategy via cation@anion dopants to boost the electrochemical performance of nickel-rich cathodes for lithium-ion batteries.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2024
·Vol. 53
·期 6
·2526-2533
·
IF 3.5
Jia-Min Lyu,Shen Yu,Zhan Liu,He-You Du,Ming-Hui Sun,Chun-Mu Guo,Yi-Long Wang,Yu Li,Li-Hua Chen,Bao-Lian Su
Excessive emission of CO2 into the atmosphere has severely impacted the global ecological environment. Converting CO2 into valuable chemicals and fuels is of great significance for sustainable development. However, low activity and undesirable selectivity often result from the inherent inertness of CO2. Herein, K- or/and Zn-modified Fe-based catalysts were prepared by an incipient-wetness impregnation method for CO2 hydrogenation via a cascade reaction. The results indicate that K species exist as K2O while Zn species exist as ZnFe2O4. In the CO2 hydrogenation pathway, K2O facilitates the adsorption of CO2 and restrains the adsorption of H2, accelerating the transformation of CO2 into C2–C4 olefins rather than paraffins while Zn species promote the dispersion of Fe species, leading to improved activity. Synergistically, a K- and Zn-modified Fe-based catalyst (2Zn–10K–Fe/Al) shows excellent catalytic CO2 hydrogenation activity, achieving a CO2 conversion of 77% which is 1.8 times that (42%) of the unmodified Fe-based catalyst (Fe/Al). Our catalyst also shows a significantly promoted selectivity to C2–C4 olefins of 17% in comparison with the Fe/Al catalyst (0%). It is envisioned that such a binary effect of elements might contribute to the low-cost and industrial production of Fe-based catalysts for selective CO2 conversion.
研究领域:
催化化学
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环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2017
·Vol. 41
·期 3
·732-739
·
IF 2.557
Dan Feng,Yan Xia
A Cr-based metal–organic framework, namely, MIL-101(Cr), was modified with amino (NH 2 –) and urea (UR 2 –) groups, and the materials were evaluated as adsorbents for glyphosate, and a comparison with commercial activated carbon was also discussed. The effects of the adsorption factors, such as adsorbent concentration, adsorption time, pH and ionic strength were mainly investigated. The results showed that a pseudo-second-order rate equation described the adsorption kinetics mechanisms well, while the Langmuir model and the Freundlich model fitted different adsorption isotherms, respectively. Among the adsorbents we studied, NH 2 -MIL-101(Cr) showed the maximum adsorbing capacity, which is 64.25 mg/g when pH = 3.0, while UR 2 -MIL-101(Cr) did not reach the best adsorption performance due to the steric hindrance. The work opens up a new way for the modification of metal–organic frameworks for adsorption process.
研究领域:
环境科学
·
材料科学
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DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 33
·18355-18362
·
IF 2.936
Chun Sing Kam,Tik Lun Leung,Fangzhou Liu,Aleksandra B. Djurišić,Mao Hai Xie,Wai-Kin Chan,Ying Zhou,Kaimin Shih
We have investigated lead adsorption on different forms of nanostructured carbon, namely multiwall carbon nanotubes (MWCNT) and reduced graphene oxide (RGO) functionalized with different functional groups (hydroxyl, carboxyl, and amino groups). We found that the same functional group does not result in the same performance trends for different nanostructured carbons. Drastically different behavior was observed for the amino-group functionalization, where a significant improvement is observed for MWCNT, while worse performance compared to non-functionalized material is obtained for RGO. On the other hand, hydroxyl and carboxyl group functionalization improves the lead adsorption regardless of the form of carbon. The best performing RGO sample, namely carboxyl group functionalized one, exhibited maximum lead adsorption capacity of 298.49 mg g−1 which was significantly higher than that of the best performing MWCNT sample (amino-functionalized MWCNT, 58.547 mg g−1).
研究领域:
环境科学
·
纳米材料学
·
水处理技术
·
环境化学
·
吸附科学
·
材料化学
✓ 已验证
DOI
高影响因子
BIOMACROMOLECULES
·
2025
·
IF 5.4
Xiaoxiong Jin,Wanying Wang,Hui Liu,Jing Zhao,Pengfei Li,Aoting Li,Ziyuan Song
Poly(l-glutamic acid)s (PLGs) are promising bone-targeting ligands due to their high molecular weight and facile preparation. Nevertheless, the bone-targeting efficiency of PLGs is still relatively low, validating the necessity to further enhance targeting through structural optimization. Herein, we report the use of a heteropolypeptide strategy to improve the bone targeting of PLGs through the incorporation of another side-chain functionality for enhanced affinity with bone tissues. Specifically, the introduction of cationic amino or aromatic phenolic side-chain residues resulted in a ∼2.3-fold or ∼1.6-fold increase in the in vivo bone targeting, respectively. Cationic modification not only improved the affinity with bone minerals but also exhibited prolonged retention in the bone tissues for more than 60 days. This work highlights the use of a heteropolypeptide library to screen and optimize the performance of polypeptide materials, offering promising bone-targeting polymeric materials for the design of bone-related nanomedicine.
研究领域:
生物材料学
·
药剂学
·
纳米医学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Catalysis Science & Technology
·
2024
·
IF 4.4
Qianqian Shang,Hongbing Wang,Changjie Kan,Rui Ding,Yankai Li,Shiva Pandeya,Ziliang Li,Mahesh Kumar Joshi
Exfoliation and hetero-element doping are common procedures for band gap engineering and enhancing the photocatalytic properties of g-C3N4. A novel and facile strategy for simultaneous exfoliation and hetero-element doping is still in high demand. Herein, we prepared hydroxide and fluoride doped ultrathin g-C3N4 nanosheets through the single-step solvothermal exfoliation of bulk g-C3N4 (BCN) using varying concentrations of ethanol and hydrofluoric acid (HF). The microscopic and spectroscopic analysis confirmed the doping of hydroxide groups and fluoride groups (HO−/F− groups) into g-C3N4 nanosheets (HF-CNS). The HO− groups are primarily located at the terminal amino groups of the heptazine rings in HF-CNS, while the F− groups are likely incorporated into the g-C3N4 lattice by forming C–F bonds. The UV-vis absorption spectra and DFT calculations showed that the electronic band structure, and hence charge carrier recombination, can be tuned by varying the HF amount during the exfoliation process. BET-specific surface area was increased from 18.65 m2 g−1 for BCN to 159.87 m2 g−1 for HF-CNS. The transient photocurrent increased from 5 μA to 20 μA. HF-CNS significantly improved the photocatalytic degradation of tetracycline, achieving 99% removal in 50 minutes, compared to 20% for BCN. Tetracycline degradation followed pseudo-first-order kinetics, with apparent rate constants (K) increasing from 0.0028 min−1 for BCN to 0.0793 min−1 for HF-CNS, a 30-fold enhancement. The photocatalytic hydrogen evolution for HF-CNS was 11 times higher than that of BCN. The HF-CNS exhibited remarkable stability and reusability, indicating its potential as a promising photocatalyst for green hydrogen production and degradation of organic pollutants.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）