JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
·
2016
·
IF 3.958
Lei Zhao,Baoyue Zhang,Xin Xiao,Feng Long Gu,Rui-Qin Zhang
Active species such as holes, electrons, hydroxyl radicals ( OH), and superoxide radical anions ( O 2 − ) involved in the photocatalytic oxidation of benzyl alcohol (BA) into benzaldehyde (BAD) on TiO 2 under ultraviolet (UV) light were investigated by adding corresponding scavengers. The experimental results show that the oxidation of BA into BAD is driven mainly by the holes and OH radical. The role of dissolved O 2 was studied by bubbling N 2 through the reaction. The results show that the dissolved O 2 is, to some extent, the source of OH. Additional density functional theory (DFT) calculations identified two H-abstraction pathways ( R abs OH and R abs α). The structure of the R abs OH product is less stable and tends to transfer resulting in the R abs α product. The holes are the main driving force for the abstracting of H from BA. The OH radical combines with the H-abstract product to form a precursor of product BAD, detected by LC–MS technique ( m / z 123), which then undergoes an intramolecular dehydration reaction to form BAD. The results will help to select the optimal active species for the photocatalytic oxidation of BA into BAD on TiO 2 under UV light.
研究领域:
物理化学
·
光催化
·
环境化学
·
材料化学
·
理论计算化学
✓ 已验证
DOI
高影响因子
CATALYSIS TODAY
·
2017
·
IF 4.636
Nianjun Hou,Ping Li,Tianmu Lv,Tongtong Yao,Xueli Yao,Tian Gan,Lijun Fan,Pengzhi Mao,Yicheng Zhao,Yongdan Li
Sm 0.5 Ba 0.5 MnO 3-δ (SBMO) has been synthesized with the Pechini method and investigated as an anode material of solid oxide fuel cells with H 2 and methanol as fuels. A cubic perovskite structure is formed after reduction. The reduction process of SBMO is studied with X-ray photoelectron spectroscopy and temperature programmed reduction techniques. The electrical conductivities of an SBMO sample sintered at 950 °C are 1.15 and 0.10 S cm −1 at 850 °C in air and H 2 , respectively. A single cell with an SBMO anode layer and a 300-μm La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ electrolyte layer exhibits a maximum power density ( P max ) of about 150 mW cm −2 at 850 °C with H 2 as fuel. The electrical conductivity of the anode layer with methanol as fuel is improved by the moderate carbon deposition, and the P max increases to about 415 mW cm −2 . The cell fed with methanol also shows a promising stability.
研究领域:
材料科学
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能源化学
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电化学
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无机非金属材料
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燃料电池技术
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2013
·Vol. 129
·期 6
·3473-3481
·
IF 1.395
Wan-Zhong Lang,Hai-Yan Niu,Ya-Xin Liu,Chun-Xia Liu,Ya-Jun Guo
The waste perfluoro-ion-exchange membranes (PFIEMs) in chlor-alkali industry were regenerated and used to the separation of dimethyl carbonate (DMC)/methanol (MeOH) mixtures by pervaporation process. The energy-dispersive spectrum (EDS) demonstrates that the impurities on the surfaces of waste PFIEMs can be effectively cleared by the regeneration process. The degree of swelling, sorption, and pervaporation properties of the regenerated PFIEMs with different counter ions were investigated. The results indicate that the counter ions of PFIEMs conspicuously influence the degree of swelling, sorption, and pervaporation properties for DMC/MeOH mixtures. The degree of swelling and solubility selectivity both decreases with the alkali metal counter ions in the sequence: Li + > Na + > K + > Cs + . The degree of swelling increases with MeOH concentration increasing in feed liquid. The pervaporation measurements illustrate that the permeation flux decreases and the separation factor increases with the rising in ion radius of counter ions. The increase of feed concentration (MeOH) and feed temperature is advantageous to improve permeation flux while at the cost of separation factor decreasing. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
研究领域:
高分子材料
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化学工程
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膜科学与技术
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环境化工
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分离科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2016
·Vol. 42
·期 4
·2045-2053
·
IF 3.205
Jing-Jia Zhang,Xu-Lei Sui,Lei Zhao,Li-Mei Zhang,Da-Ming Gu,Zhen-Bo Wang
Molybdenum trioxide (MoO 3 ) has been considered an advanced auxiliary support for Pt nanoparticle anchorage due to its excellent activity and stability. Nevertheless, its non-conductivity property still impedes its applications in electrocatalytic fields. Thus, the MoO 3 and carbon composite of a nanostructure is synthesized through sintering process and served as an efficient co-support for Pt-based anode catalyst in this paper. The electrochemical measurements demonstrate that Pt/MoO 3 -C catalyst shows higher catalytic activity and stability than the as-prepared Pt/C. Significantly, it exhibits 1.95 times higher activity and 2.36 times better durability for methanol oxidation when compared with commercial Pt/C. The remarkably enhanced performance of this novel Pt/MoO 3 -C catalyst for methanol electrooxidation can be ascribed to the abundant Pt nucleation active sites, uniformly dispersed Pt nanoparticles and the strong metal-support interaction between Pt and MoO 3 -C. These outstanding properties suggest Pt/MoO 3 -C a promising catalyst for practical application of fuel cell.
研究领域:
电催化
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纳米材料
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能源化学
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燃料电池
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电化学
✓ 已验证
DOI
高影响因子
Applications in Energy and Combustion Science
·
2022
·
IF 0
Bingzhi Liu,Long Zhu,Qingbo Zhu,Hao Lou,Qiang Xu,Zhandong Wang
Ozone-assisted combustion is an advanced combustion technology that is considered a promising means for the active control of combustion. Ozone addition can enhance combustion processes and extend the experimental parameters to extreme conditions. In this work, ozone-assisted low temperature oxidation of methanol and ethanol in a jet-stirred reactor (JSR) was carried out at atmospheric pressure, with a fuel initial mole fraction of 0.005, an equivalence ratio of 0.28, and in the temperature range of 330–800 K. Significant conversions of methanol and ethanol were observed in the low temperature region when ozone was added. Numerous intermediate species were analyzed and quantified by synchrotron vacuum ultraviolet photoionization mass spectrometry and gas chromatography, which are crucially important for unraveling the low temperature oxidation reaction network. The kinetic model of NUIGMech1.1 is tentatively updated to better explain the measured results, although the improvements of the C 1 –C 2 core mechanisms are difficult. Ozone addition enhances the action of the reaction channel of related radicals. Model analysis shows that the kinetics of Ö/ȮH/HȮ 2 atoms/radicals are crucial for the overall reaction progress, as well as the reaction of HȮ 2 radicals with ozone, which mainly contributes to the formation of ȮH radicals during the initial reaction stage. Inconsistency between measurements and model predictions highlights the considerable uncertainty in the C 1 -C 2 alcohols subchemistry at lower temperatures. The experimental results obtained in this work and model development will motivate further study of the low temperature oxidation chemistry of methanol and ethanol.
研究领域:
化学工程
·
燃烧化学
·
反应动力学
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能源化学
·
大气压反应器
✓ 已验证
DOI
CHINESE JOURNAL OF CATALYSIS
·
2015
·Vol. 36
·期 10
·1726-1732
·
IF 1.964
Huanhui Chen,Xiaoci Li,Guoqing Zhao,Hongbo Gu,Zhirong Zhu
The side-chain alkylation of toluene represents a novel, environmentally friendly, and low cost route for the production of styrene . However, the yield of styrene produced in this way is currently low, and the mechanism responsible for the side-chain alkylation of toluene is poorly understood. Furthermore, the reason for the higher catalytic efficiency of CsX over NaX and KX remains unclear. In this work, the free radical mechanism of the side-chain alkylation of toluene over basic zeolite X has been elucidated using quantum chemical calculations , together with isotope tracing experiments and the reaction between p -nitrotoluene and methanol. The adsorption isotherm of methanol showed that Cs + ions could block methanol from accessing the β-cage, which is where the side-chain alkylation reaction occurred. Furthermore, the H–D exchange results between toluene and deuterated toluene (C 6 D 5 CD 3 ) showed that CsX was more efficient as a catalyst than KX for the conversion of toluene to the corresponding benzyl radical (C 6 H 5 CH 2 • ). These two results therefore explain the higher catalytic activity of CsX towards side-chain alkylation than KX. Based on the free radical mechanism, the selectivity of styrene could be increased from 17.4% to 59.4% using CO 2 as carrier gas instead of N 2 .
研究领域:
物理化学
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催化化学
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材料化学
·
反应机理
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理论化学
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能源化学
·
环境化学
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2015
·
IF 6.217
Qin Wang,Yingjun Li,Baocang Liu,Guangran Xu,Geng Zhang,Qi Zhao,Jun Zhang
A series of well-dispersed bimetallic Pd@Pt nanodendrites uniformly supported on XC-72 carbon black are fabricated by using different capping agents. These capping agents are essential for the branched morphology control. However, the surfactant adsorbed on the nanodendrites surface blocks the access of reactant molecules to the active surface sites, and the catalytic activities of these bimetallic nanodendrites are significantly restricted. Herein, a facile reflux procedure to effectively remove the capping agent molecules without significantly affecting their sizes is reported for activating supported nanocatalysts. More significantly, the structure and morphology of the nanodendrites can also be retained, enhancing the numbers of active surface sites, catalytic activity and stability toward methanol and ethanol electro-oxidation reactions. The as-obtained hot water reflux-treated Pd@Pt/C catalyst manifests superior catalytic activity and stability both in terms of surface and mass specific activities, as compared to the untreated catalysts and the commercial Pt/C and Pd/C catalysts. We anticipate that this effective and facile removal method has more general applicability to highly active nanocatalysts prepared with various surfactants, and should lead to improvements in environmental protection and energy production.
研究领域:
纳米催化
·
电化学
·
材料化学
·
能源化学
·
表面科学
·
燃料电池
✓ 已验证
DOI
高影响因子
CATALYSIS TODAY
·
2018
·
IF 4.667
Xintong Zhou,Chang-jun Liu
Structured porous carbon materials have been extensively applied for catalyst, sensor, adsorbent, energy storage materials and many others. However, the preparation of such carbon materials in a controllable way remains a significant challenge. In this work, 3D printing has been employed to prepare porous carbon structures with tailorable pore sizes. A starch/gelatin ink has been applied as carbon source with SiO 2 monodispersed spheres as hard template. The process exhibits an excellent printing accuracy. Controllable meso and macro structures can be thereby obtained. The printed monolithic structures have been used as metal-free catalysts for the selective oxidation of benzyl alcohol, as an illustration. The monolithic and meso/macro-porous structure has a remarkable influence on the reaction rate. A high conversion with high benzaldehyde selectivity has been achieved. The 3D printing strategy provides us a simple, low cost and reliable way of fabricating carbon structures with designable meso/macro-pores, which is promising for many other applications beyond catalysis.
研究领域:
材料科学
·
催化化学
·
能源材料
·
纳米结构材料
·
功能材料
✓ 已验证
DOI
高影响因子
Green Energy & Environment
·
2019
·Vol. 4
·期 4
·424-431
·
IF 0
Yangyang Zhang,Xinli Tong,Linhao Yu,Lingwu Meng,Pengfei Guo,Song Xue
The catalytic transformation of furfuryl alcohol and hexose into value-added chemicals have been investigated with a series of polymer-based catalysts including poly(styrenesulfonic acid) (PSS), graphite oxide-doped poly(styrenesulfonic acid) (PSS-GO), and graphite-doped poly(styrenesulfonic acid) (PSS-C). It is found that the selective conversion of furfuryl alcohol to methyl levulinate (MLE) was successfully performed with PSS as the catalyst, in which a 96.4% yield is attained in methanol solvent. Moreover, the efficient dehydration of d -fructose to produce 5-hydroxymethylfurfural (HMF) has also been achieved using PSS-GO as the catalyst, where a 76.5% yield of HMF was obtained in N -methylpyrrodinone solvent. The effects of reaction temperature, time and solvent were investigated. Furthermore, the used catalysts have been respectively characterized by XRD, TG, FTIR, SEM and TEM techniques to reveal the physical properties and structures of these polymeric catalytic materials.
研究领域:
催化化学
·
生物质能源
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绿色化学
·
有机转化
·
高分子材料
·
可持续化学
·
生物基化学品
✓ 已验证
DOI
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2018
·Vol. 43
·期 45
·20712-20720
·
IF 4.229
Biyao Jin,Yiqi Li,Lianhua Zhao
Bimetallic PdV/C nanoparticles have been synthesized by phase-transfer method for catalyzing the oxygen reduction reaction (ORR) in alkaline electrolytes . PdV/C nanoparticles with different V contents are spherical with a mean diameter of 3–4 nm, and the addition of V expands the lattice parameter of Pd as shown by XRD . XPS analysis indicated the binding energy of Pd 0 3d peak increased by ca. 1 eV. Density functional theory (DFT) calculations results shows d-band center of Pd down-shift after V-doping. Based on the electrocatalytic results, introducing V can improve the catalytic activity for ORR, methanol crossover tolerance and stability. Especially, Pd 4 V/C shows higher initial potential (E onset = 1.027 V), excellent methanol crossover tolerance (98.03% retained) and long-term stability (81.30% retained), which are comparable with Pt/C JM . This work provides a new method of synthesizing PdV/C nanoparticles , which have the potential to be used as the cathode electrocatalysts for fuel cells.
研究领域:
材料科学
·
电化学
·
纳米催化
·
能源材料
·
燃料电池
·
物理化学
·
表面科学
✓ 已验证
DOI
高影响因子
FUEL
·
2018
·
IF 4.908
Guoqing Wang,Yuyang Li,Lei Li,Fei Qi
Cellular instability of spherically expanding methanol/air flames was investigated in a constant-volume single-chamber cylindrical combustion vessel at initial temperatures of 373–423 K, initial pressures of 1–10 atm and equivalence ratios of 0.7–2.1. Flame morphology shows that the methanol/air flames suffer from cellular instability, especially at 5–10 atm. Stability analysis was performed to determine the logarithmic growth rate of disturbance, the critical Peclet number and the critical flame radius. The influences of initial temperature, initial pressure and equivalence ratio on cellular instability were analyzed to identify the influential factors. Both experimental results and stability analysis indicate cellular instability monotonically increases with increasing temperature or pressure and non-monotonically varies with increasing equivalence ratio. The reduced critical Peclet number and flame thickness slightly destabilize the flame surface as temperature increases. The almost unchanged critical Peclet number and the greatly reduced flame thickness with increasing pressure make the critical flame radius smaller and the flame surface more unstable at high pressures. The monotonically decreased critical Peclet number and the non-monotonically varied flame thickness result in the non-monotonic variation of cellular instability in methanol/air flames versus equivalence ratio. The critical flame radius consequently increases with increasing equivalence ratio under very rich conditions, while the corresponding flame surface becomes more smooth. The non-monotonic variation of cellular instability versus equivalence ratio is anticipated to exist widely in combustion of heavy fuels .
研究领域:
燃烧学
·
热力学
·
流体力学
·
化学动力学
·
能源工程
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Jizhen Zhu,Sixu Wang,Mohsin Raza,Yuan Feng,Jing Li,Yebing Mao,Liang Yu,Yong Qian,Xingcai Lu
Methanol is an attractive oxygenate increasingly used as primary fuel for dual-fuel combustion technology yielding beneficial thermal-efficiency and emissions in modern engines. As such, it is significant to fundamentally understand the autoignition behavior of methanol/diesel mixtures. This study measured the ignition delay times (IDTs) of methanol/diesel blends with different mixing ratios (30%, 50%, 70% methanol by mol.) on a heated shock tube and a heated rapid compression machine at temperatures of 650−1450 K, pressures of 6−20 bar, and equivalence ratios of 0.5, 1.0 and 2.0. The typical two-stage ignition characteristics with the negative temperature coefficient response were observed for dual-fuel mixtures. In general, both the total and first-stage IDTs decrease with the increment of pressure and equivalence ratio as well as diesel proportion in mixtures. The simulation results performed with a published detailed mechanism in conjunction with a tri-component diesel surrogate demonstrate generally good agreement with the experimental data at all test conditions. Moreover, a crossover of IDTs occurs at a higher temperature (~1500 K) for varying equivalence ratios, and experiment and simulation both exhibit a non-linear mixing effect of methanol addition on diesel ignition. Interestingly, simulation results clearly suggest a crossover (~940 K) for mixtures with varying methanol content at an intermediate-temperature, where the IDT of the mixture with a lower methanol ratio becomes longer as the temperature is higher than that of the crossover. Furthermore, brute-force sensitivity analyses assisted with reaction path analysis were conducted to gain deeper insights into the autoignition chemistry of dual-fuel mixtures, especially for the chemical interaction between both fuels during the low-temperature oxidation process . It is found that methanol hardly generates •OH, whereas •OH is mainly produced by the low-temperature reaction pathways of diesel. Thus, •OH is the bridge for both fuels during the ignition process. At the high methanol ratio, the H-abstraction of diesel is mainly via •HO 2 while CH 3 OH consumes a large percentage of •OH. Consequently, the competition between methanol and diesel for •OH radicals inhibits the overall reactivity of reaction network. In addition, the original data reported here lay a foundation for the development and validation of more accurate and robust dual-fuel kinetic schemes.
研究领域:
燃烧化学
·
燃料科学
·
化学动力学
·
内燃机工程
·
替代燃料技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）