JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2019
·
IF 3.47
Zhi Zheng,Jun Wang,Yi Wei,Xuejun Liu,Fengwen Yu,Jianbing Ji
La-Fe modified Si-MCM-41 (La-Fe/Si-MCM-41) catalysts were prepared by the wet impregnation method and used in catalytic cracking of soybean oil (CCS) for biofuel production. The catalysts were characterized by BET, XRD, XPS, Py-FTIR and CO 2 -TPD. The results showed that the aromatics content increased with the increase in B/L value, while the content of oxygenated compounds decreased, indicating that Brönsted acid sites were the major active sites for deoxygenation and aromatization reactions. Compared with Si-MCM-41, the Brönsted acidity of LFM-6 sharply decreased from 22.49 to 5.86 μmol g −1 . Accordingly, the aromatics content was reduced from 37.51 wt.% to 14.52 wt.% which was lower than the limitation (15 wt.%) according to the global environmental legislation. However, for the LFM-6 catalyst, the excessive loss of Brönsted acid sites and sharp decrease in BET surface area and pore volume led to the decrease in deoxygenation. As a result, the fatty acids content increased from 2.71 wt.% to 16.67 wt.% and the acid value reached 35.20 mgKOH g −1 . When the La-Fe loading increased to 15 wt.%, part of fatty acids were converted into ketones by the active sites on Fe 2 O 3 /La 2 O 3 and strong Lewis acid sites on catalysts. Besides, the new weak Lewis acid and basic sites on Fe 2 O 3 /La 2 O 3 exhibited the synergistic effect on promoting the generation of alkenes. The CaO/LFM-6 composite catalysts prepared by the mechanical mixing of LFM-6 and CaO were used in CCS to reduce the acid value of biofuel. LFM-6-C-3 was proved to be an effective catalyst for CCS to produce biofuel with low aromatics (12.31 wt.%) and fatty acids (2.76 wt.%) content.
研究领域:
催化
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生物燃料
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化学工程
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环境科学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Rui Wang,Xianjie Liu,Haichao Wei,Yanheng Xu,Ruxian Zhou,Zhaohui Huang,Huasheng Zhan,Shulong Ma,Chen Yang
In this work, high temperature resistant materials based on waste electrical porcelain were prepared successfully by pressureless sintering method using waste electrical porcelain with different particle sizes, flint clay and dolomite as raw materials. Effects of sintering temperature and different amounts of flint clay on the properties of the prepared high temperature resistant materials were investigated. The analysis of XRD suggested that the temperature promoted the calcium aluminum silicate → gehlenite → anorthite phases transformation, which can also be proved from SEM images. The mechanical properties and volume stability of materials were improved by the formation of a large amount of interwoven plate-like anorthite. Besides, excessive sintering temperature (1300 °C) had adverse effects on microstructure and mechanical properties . The appropriate amount of flint clay additions led to more plate-like anorthite productions. With 30 wt% addition of flint clay, the sample exhibited the optimum comprehensive performance after sintering at 1250 °C showing the highest flexural and compressive strengths of 32.83 MPa and 89.59 MPa. The bulk density and apparent porosity of samples were 2.21 g/cm 3 and 3.27%, respectively. This study provides an experimental basis for the large-scale high-value utilization and recycling of waste electric porcelain.
研究领域:
材料科学
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环境工程
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陶瓷学
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产品关联
DOI
高影响因子
Sustainable Energy & Fuels
·
2021
·Vol. 5
·期 14
·3744-3754
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IF 6.367
Wangda Qu,Zizhu Zhao,Jie Wang,Fengying Dong,Hui Xu,Xinzhi Sun,Hong Jin
A facile and additive-free approach was developed to synthesize pure lignin-derived porous carbon for highly flexible supercapacitor electrodes. Lignin was simply melted on a carbon cloth, and then subjected to direct laser writing (DLW). It was found that lignin was transformed into 3D porous graphene while bonding on the carbon cloth. The fabricated materials (LCE) under different laser powers were all confirmed as having a sharp (002) peak with small d002 spacing from the XRD profile, and a high IG/ID ratio from Raman spectra. The LCEs showed promising capacitive behaviors in electrochemical testing. The best LCE (i.e., LCE40) possesses a CA of 786 mF cm−2, and it was further characterized by XPS and HRTEM to determine its compositional and structural information. Moreover, LCE40 had super flexibility attributed to carbon cloth as the substrate. The CA of the LCE after bending remained at 93–97% under different current densities. When assembled into symmetric solid-state supercapacitors, the LCE40-based device showed an areal capacitance of 148.6 mF cm−2, which is much superior to all other reported laser-induced lignin-derived carbon. This one-step process is innovative and simpler than any other porous carbon fabrication and provides a method for fabricating lignin-derived flexible supercapacitors.
研究领域:
材料科学
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电化学
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纳米技术
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能量存储
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2022
·
IF 6.449
Liangyun Sun,Juan Han,Jiacong Wu,Wenrui Huang,Yuanyuan Li,Yanli Mao,Lei Wang,Yun Wang
The special molecular structure and properties of cellulose restrict its resource utilization. In this work, two kinds of common inorganic salt hydrates (ZnBr 2 ·RH 2 O and FeCl 3 ·RH 2 O) were used to pretreat microcrystalline cellulose (MCC) by magnetic stirring method at temperatures below 80 °C. It was found that while high temperatures could shorten the dissolution time of MCC, while inorganic salt hydrates with either low water (ZnBr 2 ·3.5H 2 O and FeCl 3 ·5H 2 O) or high water (ZnBr 2 ·5H 2 O and FeCl 3 ·8H 2 O) content can prolong the dissolution time of MCC. The reactivity of regenerated cellulose (RC) after dissolution was evaluated by enzyme hydrolysis reaction. Moreover, ZnBr 2 ·4H 2 O and FeCl 3 ·6H 2 O have better pretreatment effect. The structure and surface morphology of MCC before and after pretreatment were investigated by XRD , FT-IR, SEM , AFM and TGA. The MCC was converted from cellulose Ⅰ to cellulose II through the pretreatment. With the extension of dissolution time, the strength of hydrogen bond and thermal stability of RC were both slightly weakened, Moreover, the crystallinity and degree of polymerization (DP) of RC decreased, and the surface morphology of RC was more rougher, more uneven and dispersed compared with the smooth and compact MCC. The adsorption rate curves showed that RC-ZnBr 2 ·4H 2 O was more conducive to the adsorption of cellulase , thereby accelerating the rate of RC hydrolysis. Furthermore, ZnBr 2 ·4H 2 O is a well reusable pretreatment solvent that can maintain a good pretreatment effect on cellulose after five cycles.
研究领域:
化学工程
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材料科学
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生物材料
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生物技术
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2022
·
IF 7.336
Sijie Gao,Shuozhen Hu,Guoming Luo,Shigang Sun,Xinsheng Zhang
Doping nitrogen (N) into the carbon support was widely applied to enhance the performance of Pd toward formic acid electro-oxidation (FAO). However, traditional nitrogen doping methods can only introduce a low content of nitrogen as well as a two-step complicated procedure to synthesize catalysts. In this study, a facile one-pot strategy is demonstrated to prepare N-doped carbon encapsulated palladium nanoparticles (Pd@N x C) via the pyrolysis of 2,2′-bipyridine palladium (II) complexes. A N-doped carbon layer with the thickness of about 4 nm is in-situ generated over Pd nanoparticles by only one pyrolysis procedure. Both XPS and in-situ XRD results suggest that metallic Pd is reduced from Pd 2+ by the complexed N in bipyridine during the pyrolysis at high temperature. The physical characterizations prove that the in-situ formation of N-doped carbon shell can not only effectively prevent the agglomeration or dissolution of Pd nanoparticles, but also promote the charge donation from the carbon layer to Pd, and maintain the structure of Pd atom complexed to two pyridinic-N atoms (Pd-N). This in-situ synthesis strategy can be successfully applied to carbon supports with different geometry, such as reduced graphene oxide and Vulcan XC-72. Pd@N 3 C/rGO, which contains the highest amount of N (7.39 at.%) and Pd-N (33.15%), shows the highest specific activity (5.88 mA cm −2 ) and excellent durability toward FAO.
研究领域:
材料科学
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电化学
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催化
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2013
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IF 5.825
Xing Tang,Huawei Chen,Lei Hu,Weiwei Hao,Yong Sun,Xianhai Zeng,Lu Lin,Shijie Liu
A series of low-cost readily-assembled eco-friendly metal hydroxides were examined as catalysts in the synthesis of a novel platform molecule, γ-valerolactone (GVL), from biomass-derived ethyl levulinate (EL) via hydrogen transfer reaction. Among these catalysts, ZrO(OH) 2 · x H 2 O was found to be most active. EL conversion of 93.6% and GVL selectivity of 94.5% were achieved when 2-propanol was used as a hydrogen donor at 473 K with a reaction time of only 1 h. The complete reaction pathway and the probable main by-products for the conversion of EL to GVL were clearly deduced for the first time. The ZrO(OH) 2 · x H 2 O catalyst could be reused at least ten times without any significant loss of catalytic activity. Furthermore, characterizations were carried out on the fresh and spent ZrO(OH) 2 · x H 2 O catalysts with XRD, FT-IR, BET, TGA-DTA. Combined with the results of poisoning experiments, a plausible mechanism for catalytic transfer hydrogenation (CTH) of EL to GVL was proposed to be consisted of a catalytic cycle involving a six member ring transition state.
研究领域:
化学工程
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催化
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绿色化学
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可再生能源
✓ 已验证
产品关联
DOI
高影响因子
HIGH TEMPERATURE MATERIALS AND PROCESSES
·
2021
·Vol. 40
·期 1
·389-396
·
IF 0.826
Yingwei Xu,Tingting Zhang,Li Zheng,Ailing Zou
KBaPO 4 :Eu 2+ /Sm 3+ phosphor was synthesized via the high-temperature solid-phase reaction method. The structural properties, surface morphology, and optical properties of the synthesized samples were obtained by the X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and fluorescence measurements. The XRD patterns indicate that the crystal structure of KBaPO 4 has not been changed by co-doped with two rare-earth ions. Under the excitation of 400 nm, the Eu 2+ and Sm 3+ co-doped KBaPO 4 phosphors showed typical emission peaks at 430 (blue), 562 (yellow), and 600 nm (red). Meanwhile, with the increase of the Sm 3+ content, the photoluminescent (PL) emission intensity of Sm 3+ increased until the content reaches 0.12. However, the PL intensity of Eu 2+ ions gradually decreased, which indicated that there was a possible energy transfer between the two ions. Therefore, the obtained results indicated that Eu 2+ /Sm 3+ co-doped KBaPO 4 is a promising phosphor for the use in white light-emitting diodes with near ultraviolet chips.
研究领域:
材料科学
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光电技术
·
固体物理
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产品关联
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Cong Wang,Gang Li,Hongchen Guo
Compared with the mainstream approaches of doping the active metal in the MOFs structure and post-synthetic modification, it is more convenient to directly use the coordinatively unsaturated metal sites of MOFs for catalytic reactions. Herein, two forms of Ni-MIL-77 (1D Ni-MIL-77 and 3D MIL-77) were prepared using one-pot method and characterized by ICP-AES, XRD, FT-IR, XPS and SEM. Among them, 1D Ni-MIL-77 without high temperature heat treatment exhibited a better heterogeneous catalytic ethylene dimerization activity that was up to 989.6 g pro. /(g cat. ·h) (TOF=5544 h −1 ) and the selectivity of 1-butene could reach 93.3% at the optimal conditions. In addition, a probable Cossee-Arlman-like mechanism was proposed. By studying the catalyst structure after reaction, it was found that the reason for limited reuse was the hydrolysis products of the co-catalyst covered the catalysts.
研究领域:
催化
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材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES
·
2023
·Vol. 78
·期 11
·1061-1067
·
IF 1.8
Arif Ullah,Jinghao Zhuang,Zheng Liu,Xiaozhan Yang,Wenlin Feng
In this work, the phosphors of Eu 3+ ions doped Ba 2.9 Sr 0.1 WO 6 were successfully synthesized by the high-temperature solid-state method. The luminescence properties, including the emission and excitation spectra, fluorescent lifetimes, and CIE chromaticity coordinates were characterized. The crystal structure and composite of the samples were investigated by XRD (X-ray diffraction), and HRTEM (high-resolution transmission electron microscope). The emission spectra consist of the characteristic peak of Eu 3+ excitation at 393 nm; the leading emission peak at 618 nm can be ascribed to the transition of 7 F 0 → 5 L 6 . The optimal red emission is achieved by 2 % Eu 3+ doping. This red Ba 2.9 Sr 0.1 WO 6 : Eu 3+ has good luminescent properties and may have potential application in white LEDs.
研究领域:
材料科学
·
光电材料
·
荧光粉材料
✓ 已验证
DOI
高影响因子
ChemElectroChem
·
2016
·Vol. 4
·期 2
·340-344
·
IF 3.506
Yan Li,Pinwwei Cai,Suqin Ci,Zhenhai Wen
Graphical Hydrogen evolution catalyst : Nanohybrids of Ni 2 P nanofilms on carbon nanosheets show high catalytic activity and excellent stability for the hydrogen evolution reaction in pH-universal electrolyte. A reliable strategy has been developed to prepare Ni 2 P nanofilms on carbon nanosheets (CNS) nanohybrids (Ni 2 P/CNS), which involves the preparation of three-dimensional (3D) CNS followed by in situ growth of Ni 2 P nanofilms on the surface of CNS. The Ni 2 P/CNS nanohybrids possess a robust 3D hierarchical structure, in which the Ni 2 P films are solidly overlaid on the surface of the CNS. The Ni 2 P/CNS nanohybrid was characterized by a variety of techniques, including X-ray diffraction (XRD), electron microscopy, X-ray photoelectron spectroscopy (XPS), etc. A series of electrochemical tests demonstrate the Ni 2 P/CNS nanohybrid shows high catalytic activity and excellent stability towards the hydrogen evolution reaction (HER) in pH-universal electrolyte, that is, in acidic, neutral, and basic media. The outstanding performance for Ni 2 P/CNS is correlated with the synergic effects between Ni 2 P and CNS associated with its unique and robust structure.
研究领域:
材料科学
·
纳米技术
·
电化学
·
能量转换
·
催化
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2021
·
IF 6.498
Yanan Cai,Jing He
The release of Mn(II) occurs in the degradation of organic matters by manganese ore (MnO 2 ), resulting in a reduced efficiency. During the degradation of ciprofloxacin (CIP), in a biofilter, this paper put forward a novel method that similar to the geo-cycle of Mn (MnCS) on the Earth to regenerate MnO 2 . The freshly prepared MnO 2 was suitable for the use in the MnCS. It indicated that the mutual conversion between Mn(II), Mn(III), and Mn(IV) in the MnCS, which was driven by CIP and manganese oxidizing bacteria (MnOB), could maintain the activity of MnO 2 . The MnCS showed feasibility in the coexistence of ammonia or humic acid , and provided a kinetic degradation. The physicochemical features of MnO 2 before and after bio-regeneration were characterized by TEM , XRD, BET, and XPS. It was found that the morphological structure of MnO 2 became loose and the maximum peak of pore size distribution became smaller, but the increase of surface area, the change of Mn(III/IV) content, and the decrease of crystallinity favored the bio-regeneration process. Moreover, as a mediator in the MnCS, the group of MnOB was dramatically inhibited by CIP, and the bacterial community had changed significantly. The typical MnOB shared low abundance in the biofilter, while the rarely reported genera (e.g. Sphingomonas ) that related to the formation of Mn deposits appeared to be involved in the MnCS.
研究领域:
环境科学
·
微生物学
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化学
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生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2017
·
IF 6.035
Li Peng,Xiaohan Xu,Xun Yao,Hua Liu,Xuehong Gu
A series of novel hierarchical ZSM-5 zeolite membranes with tunable mesopore sizes have been prepared successfully by using amphiphilic organosilane 3-[(trimethoxysilyl) propyl]octyldimethyl-ammonium chloride (TPOAC) as the mesogenous template and part of the Si source. The effects of several synthesis parameters, such as the TPOAC/SiO 2 ratio, synthesis temperature and crystallization time, on the microstructures and rejection performance of the hierarchical ZSM-5 zeolite membranes were systematically investigated. Multiple techniques, such as XRD , SEM, N 2 adsorption techniques, TEM, IR, 13 C MAS NMR and 29 Si MAS NMR were employed for the characterizations. The filtration of dextran in water shows that the membranes have molecular weight cutoff (MWCO) ranging from 9500 to 943,000, corresponding to the molecular size in the range of 4.5–37 nm. The sharp increase in the rejection of dextran with the increase of molecular weight indicated narrow pore size distribution of the membrane. These results show that the hierarchical mesoporous ZSM-5 zeolite membranes have a great potential for ultrafiltration with high performance.
研究领域:
材料科学
·
化学工程
·
膜技术
✓ 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）