ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Changzhou Chen,Peng Liu,Haihong Xia,Jianchun Jiang,Xiaohui Yang,Minghao Zhou
Lignin is an abundant source of aromatics with low effective hydrogen-to-carbon ratio (H/Ceff), and the depolymerization of lignin provides significant potential for producing liquid products with an improved H/Ceff value. In this work, the catalytic conversion of lignin monomers, dimer, trimers, and realistic lignin over spherical MOF-derived NiMo@C catalysts was well established, to get liquid fuels with a higher H/Ceff. The optimal ratio of the Ni4Mo1@C catalyst exhibited good hydrodeoxygenation activity and stability for the hydrotreatment of lignin model compounds and lignin. The addition of Mo facilitated the decrease of the particle size of a spherical structure, strengthened the electron-transfer capability between metals Mo and Ni, and enhanced the acid strength. All of these factors contributed to higher hydrodeoxygenation activity in the hydrotreatment process. Up to 100% conversion and 90% yields of ethylcyclohexane and cyclohexanol with H/Ceff values of 2.0 and 1.667, respectively, were obtained. The Ni4Mo1@C catalyst achieved a decrease of the oxygen element and an increase of H/Ceff and HHV values. The physicochemical characterizations were performed by various means including X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), H2-temperature-programmed reduction (H2-TPR), NH3-temperature-programmed desorption (NH3-TPD), pyridine-infrared spectroscopy (Py-IR), inductively coupled plasma emission spectrometer (ICP), and Raman and X-ray photoelectron spectroscopy (XPS) analyses, which definitely elucidated the formation of a synergistic effect between metals Mo and Ni. Additionally, a control experiment also illustrated the synergistic effect that facilitated the occurrence of the hydrotreatment process under lower temperatures after the addition of metal Mo. Based on the optimal reaction condition (240 °C, 4 h, 2.0 MPa H2), both lignin and its monomers/dimers/trimers could be effectively hydrotreated to afford liquid products with improved H/Ceff value compared to raw lignin.
研究领域:
能源化学
·
催化化学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2019
·Vol. 149
·期 8
·2078-2088
·
IF 2.372
He Xiaoxia,Chen Yu,Liu Ya,Fang Lina,Chen Zeng,Ji Hongbing
Abstract A series of metal-modified hierarchical M/H-ZSM-5 catalysts were prepared for catalytic conversion of cellulose in an aqueous medium. Characterization of the catalysts showed that the impregnation of metal into H-ZSM-5 did not change the basic framework and pore structure of H-ZSM-5, but it decreased the total acidity. Analysis of the products indicated that the catalysts significantly affected products distribution. When Co/H-ZSM-5 and Fe/H-ZSM-5 were used as the catalysts, the yields of lactic acid and cyclic ketones obviously increased. At last, a recommendable catalytic transformation pathway of cellulose over M/H-ZSM-5 was proposed on the basis of the obtained experimental results and the published literatures. Graphical Abstract In this paper, a series of metal-modified hierarchical M/H-ZSM-5 (M = Ce, Co, Ga, and Fe) catalysts were prepared and employed in catalytic conversion of cellulose in aqueous media to examined the products distribution of cellulose catalytic conversion. Based on our results and previous works, the plausible general reaction pathways of cellulose over M/H-ZSM-5 were proposed.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Tian-Yu Liu,Cong Wang,Yong-Zhe Han,Chang Bai,Hai-Tao Ren,Yong Liu,Xu Han
Bi 2+x WO 6 are a group of reactive photocatalysts in the photooxidation of various contaminants. However, their catalytic reactivity in the persulfate (PS)-based oxidation processes in the absence of light is still unknown. In this study, Bi 2.15 WO 6 shows a high reactivity in the catalytic oxidation of bisphenol A (BPA) by PS in the absence of light under alkaline conditions, and 20 mg L -1 BPA can be rapidly removed within 30 min at pH 10.0 with the low stoichiometry ratio of 1.79 between consumed PS and removed BPA. Characterizations of the oxidation products indicate that 98.4% of soluble BPA has been oxidatively polymerized to BPA polymers, instead of being oxidized to CO 2 and H 2 O. FTIR, Raman, XPS and electrochemical analyses confirm that surface Bi(III) is the reactive site for the adsorption of BPA and PS, which then initiates reactions between BPA and PS. DFT calculations reveal that the O-O bond in PS is moderately activated via the nonradical pathway after adsorbing on Bi(III), instead of being decomposed to SO 4 •− , followed by H-abstraction from BPA by the activated PS with the formation of phenoxyl radicals and the subsequent polymerization to BPA polymers. The apparently lower energy barrier from adsorbed BPA (Δ G = 0.056 eV) than that from dissolved BPA (Δ G = 0.263 eV) further reveals that H-abstraction from adsorbed BPA to the activated PS on the surface of Bi 2.15 WO 6 is more favorable than that from dissolved BPA. This study gives new insight on the efficient removal of recalcitrant contaminants via the H-abstraction pathway.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF ANTIMICROBIAL AGENTS
·
2017
·
IF 4.307
Hong-Yan Luo,Ma-Feng Liu,Ming-Shu Wang,Xin-Xin Zhao,Ren-Yong Jia,Shun Chen,Kun-Feng Sun,Qiao Yang,Ying Wu,Xiao-Yue Chen,Francis Biville,Yuan-Feng Zou,Bo Jing,An-Chun Cheng,De-Kang Zhu
The Gram-negative bacterium Riemerella anatipestifer CH-2 is resistant to lincosamides, having a lincomycin (LCM) minimum inhibitory concentration (MIC) of 128 µg/mL. The G148_1775 gene of R. anatipestifer CH-2, designated lnu (H), encodes a 260-amino acid protein with ≤41% identity to other reported lincosamide nucleotidylyltransferases. Escherichia coli Rosetta TM (DE3) containing the pBAD24- lnu (H) plasmid showed four- and two-fold increases in the MICs of LCM and clindamycin (CLI), respectively. A kinetic assay of the purified Lnu(H) enzyme for LCM and CLI showed that the protein could inactive lincosamides. Mass spectrometry analysis demonstrated that the Lnu(H) enzyme catalysed adenylylation of lincosamides. In addition, an lnu (H) gene deletion strain exhibited 512- and 32-fold decreases in LCM and CLI MICs, respectively. The wild-type level of lincosamide resistance could be restored by complementation with a shuttle plasmid carrying the lnu (H) gene. The transformant R. anatipestifer ATCC 11845 [ lnu (H)] acquired by natural transformation also exhibited high-level lincosamide resistance. Moreover, among 175 R. anatipestifer field isolates, 56 (32.0%) were positive for the lnu (H) gene by PCR. In conclusion, Lnu(H) is a novel lincosamide nucleotidylyltransferase that inactivates LCM and CLI by nucleotidylylation, thus conferring high-level lincosamide resistance to R. anatipestifer CH-2.
研究领域:
微生物学
·
分子生物学
·
抗生素抗性研究
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CATALYSIS TODAY
·
2022
·
IF 6.562
Xinyi Xing,Ying Guan,Liping Zhang,Xian Shi,Han Wu,Hui Gao,Siquan Xu
A catalytic system that is both efficient and recyclable is desirable for production 5-hydroxymethylfurfural (HMF) from glucose. In this study, the catalytic system composed of H 2 O (NaCl) -tetrahydrofuran (THF) biphasic system and H-β zeolite was found to have excellent performance for the glucose conversion into HMF. The physicochemical properties of the H-β zeolite catalyst, the dosage of the system components, and the reaction parameters were investigated in detail to optimize the production efficiency of HMF. Under optimal reaction conditions, an advanced level of 84% HMF yield was obtained from glucose. After the reaction was completed, all components of the catalytic system can be recovered, realizing no waste of reagents. Moreover, the recycled H-β(30) zeolite catalyst maintained considerable catalytic stability after five consecutive cycles. Therefore, it is reasonable to believe that the efficient, inexpensive, and recyclable H 2 O (NaCl) -THF catalytic system containing H-β(30) zeolite is capable of showing promising application potential in the future.
研究领域:
催化化学
·
可再生资源转化
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2012
·Vol. 3
·期 12
·3330-3339
·
IF 5.321
Cheng-guang Mu,Xiao-dong Fan,Wei Tian,Yang Bai,Zhen Yang,Wei-wei Fan,Heng Chen
We describe the synthesis and self-assembly of a well-defined H-shaped terpolymer in this paper. A block copolymer of poly(ethylene glycol) (PEG) and poly(N,N-dimethylaminoethyl methacrylate) (PDMA), which bears an azido group at the diblock junction (PEG–N3(–PDMA)) was first prepared by atom transfer radical polymerization. Then, an alkynyl-terminated narrow distributed polytetrahydrofuran (PTHF-Alk) was synthesized as another building block via cationic ring opening polymerization. The well-defined H-shaped terpolymer was afforded by clicking PEG–N3(–PDMA) onto both chain-ends of PTHF-Alk. This H-shaped terpolymer can self-assemble into micelles with different sizes and morphologies at various solution pH values. The micellar size also exhibits temperature-dependence at pH 7.4 and 9.2. The variation of size and morphology of the micelles with the solution pH and temperature is ascribed to the pH- and thermo-responsive properties of the PDMA block.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Evidence-based Complementary and Alternative Medicine
·
2013
·
IF 1.722
Huiqing Lv,Xiaoping Zhang,XueZhi Chen,Zhijun Xie,Changfeng Hu,Chengping Wen,Kezhi Jiang
Background. Ficus pandurata H. (Moraceae) is widely used in traditional Chinese medicine as a healthy food condiment or a medicine for treatment of various diseases including inflammation. Objective. The purpose of the present study is to investigate the phytochemical compositions and antioxidant and anti-inflammatory activities of crude water (FPW) and ethanolic extracts (FPE) from Ficus pandurata H. Methods. Phytochemical compositions were identified by a high-performance liquid chromatography-electrospray ionization-mass spectrometry method (HPLC-ESI-MS). The antioxidant activities were evaluated by diphenylpicrylhydrazyl (DPPH) and hydroxyl radical assays, and the anti-inflammatory activities were evaluated by paw edema and levels of inflammatory mediator TNF-α and PGE2 in monosodium urate (MSU) crystal-induced rats. Results. Six compounds were identified by HPLC-MS method, and abundance of phenolics was found in FPE. The FPE showed concentration-dependent-significant scavenging of DPPH and hydroxyl radicals with IC50 values 118.4 and 192.9 μg/mL, respectively. The FPE treatment significantly inhibited the paw edema and the production of TNF-α and PGE2 in MSU crystal-induced rats. Conclusion. The FPE exerted stronger antioxidant and anti-inflammatory activities which may be attributed to its high phenolic content.
研究领域:
药理学
·
植物化学
·
传统医学
✓ 已验证
DOI
PubMed
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Zaixiang Xu,Fengcang Zhou,Hanchi Chen,Jianguo Wang
The regeneration of NAD(P)H and its analogues is crucial for biocatalytic processes. However, despite the efficiency of enzymatic catalysis in regenerating NAD(P)H, the sustainability of enzymes is often compromised, particularly under extreme catalytic conditions. Moreover, artificial cofactors may present advantages in certain reactions due to their stability and versatility, yet the substrate specificity of enzymes poses significant challenges to their regeneration through the enzymatic method. Therefore, it is imperative to develop a highly stable regeneration method that can be adapted to both natural and artificial cofactors. In this work, employing potassium-ion-doped carbon nitride (ionCN-0.2) as a catalyst not only achieves high-efficiency photocatalytic regeneration of NAD(P)H, comparable to that of glucose dehydrogenase (GDH), but also a remarkable ability to regenerate nicotinamide analogues. This enhanced performance stems from the tunable negative ζ-potential, which effectively adsorbs the positively charged [Cp*Rh(bpy)H2O]2+ mediator, resulting in enhanced regeneration kinetics of the nicotinamide moiety. The catalyst demonstrates superior performance compared to the reported systems; the optimal regeneration rate reaches 0.55 mmol L–1 gcat–1 min–1 and approaches enzymatic regeneration efficiency. Expanding the reaction conditions to a wider temperature and pH range also confirms the effectiveness and sufficient stability of this photocatalytic system, offering a promising strategy for stable cofactor regeneration in biocatalytic processes.
研究领域:
生物化学
·
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Food Analytical Methods
·
2015
·Vol. 8
·期 10
·2605-2611
·
IF 1.956
Peng Juan,Song Shanshan,Liu Liqiang,Kuang Hua,Xu Chuanlai
In order to develop highly sensitive immunoassays for detecting the major peanut allergen, Ara h 2, we prepared six monoclonal antibodies (mAb) with high affinity to Ara h 2. Using mAb 5 as a capture antibody and HRP-labeled mAb 1 as a detection antibody, a sandwich enzyme-linked immunoassay (ELISA) was established with a limit of detection (LOD) of 0.02 ng/mL. An immunochromatographic strip based on these two mAbs was also established with a LOD of 1 ng/mL. Both tests showed high specificity in cross-reactivity experiments. Sample analyses indicated that these two immunoassays were feasible, accurate, and highly sensitive for measuring allergen Ara h 2 of food.
研究领域:
食品科学
·
免疫学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Zhisong Liu,Haomiao Xu,Yurui Fan,Wenjun Huang,Feng Yu,Zan Qu,Naiqiang Yan
Ruthenium single-atom catalysts have great potential in ammonia-selective catalytic oxidation (NH3–SCO); however, the stable sp3 hybrid orbital of NH3 molecules makes N(sp3)–H dissociation a challenge for conventional symmetrical metallic oxide catalysts. Herein, we propose a heterogeneous interface reverse atom capture strategy to construct Ru with unique asymmetric Ru1N2O1 coordination. Ru1N2O1/CeO2 exhibits intrinsic low-temperature conversion (T100 at 160 °C) compared to symmetric coordinated Ru-based (280 °C), Ir-based (220 °C), and Pt-based (200 °C) catalysts, and the TOF is 65.4 times that of Ag-based catalysts. The experimental and theoretical studies show that there is a strong d–p orbital interaction between Ru and N atoms, which not only enhances the adsorption of ammonia at the Ru1N2O1 position but also optimizes the electronic configuration of Ru. Furthermore, the affinity of Ru1N2O1/CeO2 to water is significantly weaker than that of conventional catalysts (the binding energy of the Pd3Au1 catalyst is −1.19 eV, but it is −0.39 eV for our material), so it has excellent water resistance. Finally, the N(sp3)–H activation of NH3 requires the assistance of surface reactive oxygen species, but we found that asymmetric Ru1N2O1 can directly activate the N(sp3)–H bond without the involvement of surface reactive oxygen species. This study provides a novel principle for the rational design of the proximal coordination of active sites to achieve its optimal catalytic activity in single-atom catalysis.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2025
·
IF 13.1
Haochuan Wang,Xin Liu,Chong Wang,Wei Wang,Jinxiang Hong,Pan Feng
Ultra-early mechanical properties are critical for shotcrete performance, significantly influenced by ettringite and calcium silicate hydrate (C-S-H) formed during the initial hydration stage and free water. This study investigates the individual and synergistic effects of these phases on mechanical behavior using equivalent cement pastes. In this system, cement was entirely replaced with dolomite particles of matching size distribution, with the controlled introduction of free water, ettringite, and C-S-H. The validity of these equivalent systems was confirmed through comprehensive characterization. Mechanical performance was subsequently evaluated using compression, shear, Vickers hardness and nanoindentation tests. Results revealed that free water remarkably weakened the mechanical properties, whereas both ettringite and C-S-H enhanced strength by reducing voids and reinforcing weak particle interfaces. Ettringite primarily contributed to interparticle friction, while C-S-H enhanced cohesion at interfaces including dolomite-dolomite, dolomite-ettringite and ettringite-ettringite contacts. When co-existing, C-S-H formed within the porous ettringite network, not only establishing a multi-scale filling structure but also stabilizing the dolomite-ettringite skeleton. These findings advance our understanding of the early-age mechanical development of shotcrete and highlight the potential of equivalent cement systems as robust tools for research into cementitious materials.
研究领域:
土木工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2017
·
IF 3.169
Jinfeng Sun,Hu Shi,Binbin Qian,Zhiqiang Xu,Weifeng Li,Xiaodong Shen
This work investigates the influence of synthetic C-S-H/polycarboxylate(PCE) nanocomposites (CPNs) on the hydration and properties of hydrated cement pastes. HPEG-PCE copolymers exhibiting side chain length of 45 ethylene oxide (EO) units was utilized to synthesize CPNs by precipitating C-S-H from Na 2 SiO 3 and Ca(NO 3 ) 2 in the PCE solution. A Box-Behnken Design (BBD) for the Response Surface Methodology (RSM) was employed to statistically optimize the sizes of the resultant. The prepared CPNs were characterized by particle size distribution (PSD), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR) and thermo gravimetric/derivative thermo gravimetric (TG/DTG) analyses. The influence of CPNs on the hydration properties of cement were assessed and discussed in terms of hydration kinetics, mechanical properties, phase composition and pore structure analysis. The experimental results showed that the optimum synthetic parameters, an experimental temperature of 30.1 °C, reactant flow velocity of 0.63 ml/min and initial volume of PCE solution of 28.5 ml, produced CPNs with a minimum size of 329.12 nm. It was demonstrated that PCE polymers were either grafted on the surface or partially intercalated in the interlayer regions of C-S-H, and their introduction also increased the distance between C-S-H interlayers. Cement hydration was significantly promoted as a result of an increased heat release, even at low CPNs content. The early compressive strength of the mortar significantly improved with increasing CPNs content due to the accelerated cement hydration of the CPNs: the 0.6 wt.% CPNs content improved the compressive strength by 18.97%. Moreover, the inclusion of CPNs is advantageous for pore modification: the total porosity decreased by 25.77% after 3 days. Finally, phase composition analysis confirmed that no new crystalline phase was produced upon CPNs addition.
研究领域:
建筑材料科学
·
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）