Journal of Materials Chemistry A
·
2024
·
IF 10.7
Xiangxue Zhang,Nina Fei,Qianhong Wang,Ali Raza Khan,Wenyao Chen,Gang Qian,Jing Zhang,De Chen,Xuezhi Duan,Xing-Gui Zhou,Weikang Yuan
Oxygen vacancy regulation in metal catalysts has emerged as a crucial strategy for efficiently degrading volatile organic compounds (VOCs), while the acquisition of kinetics and mechanistic insights into the oxygen vacancy roles remains highly desirable yet challenging. Herein, we conduct a combined kinetics and mechanistic investigation into the oxygen vacancy effects of Cu catalysts on toluene oxidation. Cu catalysts with varying oxygen vacancy contents are prepared using three representative metal oxide supports, including reducible ZrO2 with strong oxygen storage capacity, reducible ZnO, and unreducible Al2O3. The toluene oxidation as well as CO oxidation are tested for these catalysts, revealing the superior catalytic activity of Cu/ZrO2 catalyst. Multiple charactrizations demonstrate that the strong reducibility and abundance of oxygen vacancies within the Cu/ZrO2 catalyst are the key factors for these reactions. A redox-based kinetics strategy is further applied to decouple the reduction and oxidation steps, thus affording a rate diagram to elucidate the promotional effects of oxygen vacancies on toluene decomposition. Additionally, in-situ DRIFTS study unveils the reaction pathway, showing the transformation from toluene to benzyl alcohol, benzaldehyde, benzoate, phenol, anhydride, carbonate, and ultimately to CO2. As a result, the oxygen vacancy-tuned rate-relevant step is disclosed, shifting from C-H bond cleavage for the Cu/Al2O3 catalyst with limited oxygen vacancies to the C=O and C=C bond cleavage for the Cu/ZnO and Cu/ZrO2 catalysts with more oxygen vacancies. The kinetics and mechanistic insights gained here would help guide the design of highly efficient oxidative catalysts by tuning the oxygen vacancies of support.
研究领域:
催化化学
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2025
·
IF 6.2
Guodong Hong,Zhenqiang Yu,Dexin Kong,Taoli Huhe,Rui Shan,Haoran Yuan,Yong Chen
Currently, the selection of iron valence states in composite-modified magnetic biochar prepared by co-pyrolysis exhibits a high degree of blindness. Therefore, this study compares the performance of biochar preparation via co-pyrolysis of three different iron valences (Fe 2 + , Fe 3+ , and Fe 6+ ) and potassium oxalate (K 2 C 2 O 4 ) composite modification for tetracycline (TC) removal. The results indicate that the co-activation of potassium oxalate with different iron valences led to the formation of magnetic biochar with varying elemental contents, morphologies, and structures. Batch adsorption experiments demonstrate that KF3-BC has a high tetracycline removal rate over a wide pH range (3 – 11) and at high coexisting ion concentrations (1 – 100 mmol/L). Furthermore, experiments with synthetic swine wastewater in different matrices, the adsorption capacity of KF3-BC for TC (at a concentration of 100 mg/L) exceeds 81.09 mg/g. Additionally, under optimal conditions of 30 °C and pH = 5, the theoretical maximum adsorption capacity (Q max ) for TC is as follows: KF3-BC (236.91 mg/g) > KF6-BC (169.42 mg/g) > KF2-BC (51.34 mg/g) > BC (38.41 mg/g). The adsorption processes of KF2-BC, KF3-BC, and KF6-BC all conform to the Pseudo-second-order and Freundlich models, implying that TC adsorption occurs at the multilayer molecular adsorption on heterogeneous surfaces, primarily driven by chemisorption. The primary adsorption mechanism between KF-BCs and TC molecules is the π–π EDA interactions. Additionally, hydrogen bonding, cation–π complexation, electrostatic interactions, and pore filling also contribute to the adsorption process. This study can assist in selecting the optimal iron source and chemical activator for composite modification of biochar for the adsorption of TC in wastewater.
研究领域:
环境科学
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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
Energetic Materials Frontiers
·
2025
·
IF 3.9
Rui-min Tang,Chen Wang,Mao-guo Zhu,Liang-liang Sun,Jian-xing Yang,Su-hang Chen,Feng-qi Zhao,Kang-zhen Xu
The pyrolysis behavior and mechanism of energetic materials are crucial for assessing their safety and application. In this study, the pyrolysis behavior, gas-phase decomposition products, condensate phase products and pyrolysis mechanism of high nitrogen compound 4,4’,6,6’-tetri(azide)-hydrazine-1,3,5-triazine (TAHT) were fully studied through differential scanning calorimetry (DSC), thermogravimetric analysis (TG), thermogravimetric-infrared-mass spectrometry (TG-IR-MS) and in-situ infrared spectroscopy. The results indicate that the thermal behavior of TAHT exhibits a big exothermic decomposition process and an endothermic decomposition process accompanied by mass loss of 42.5 % and 52.1 %, respectively. At the heating rate of 10 o C·min -1 , the peak temperature ( T p ) and decomposition enthalpy of exothermic decomposition process are 230.4 o C and -2021.0 J·g -1 , respectively. The peak temperature ( T p ) of endothermic decomposition process is 703.5 o C. In the exothermic decomposition stage, the main gas-phase decomposition products of TAHT is N 2, and contains small amounts of NH 3 and HCN, the hydrazine bond and azide groups in the condensed-phase almost completely disappear during the pyrolysis process, and the residues form a network structure of triazine ring. Based on the analysis of gas-phase and condensed-phase products, a possible pyrolysis mechanism for TAHT is proposed. This work provides valuable theoretical insights for the application of TAHT as a new green energetic material.
研究领域:
化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Sensor and Energy Materials
·
2022
·
IF 0
Wen-Xuan Fu,Ping Zhou,Wei-Liang Guo,Bin Su
As one of most advanced transduction techniques, electrochemiluminescence (ECL), such as that generated by tris(2,2′-bipyridyl)ruthenium (Ru(bpy) 3 2+ ), has been extensively used in chemical sensing and analysis, but the reaction mechanism has not been fully resolved. Aiming at gaining insightful mechanistic information on the coreactant system involving (Ru(bpy) 3 2+ ) and tri- n -propylamine (TPrA), herein we investigate the variation of thickness of ECL layer (TEL) with the concentration ratio of (Ru(bpy) 3 2+ ) to TPrA ( c Ru / c TPrA ) by ECL microscopy. Using carbon fiber as the working electrode, TEL was observed to grow with the increase of c Ru / c TPrA remarkably. In conjunction with finite element simulations, the extension of ECL layer was rationalized to be associated with the incremental contribution of so-called “catalytic route”. This route offers an additional channel of generating remote light emission in solution, apart from surface-confined emission produced by the “oxidative-reduction route”. Given the quantitative analysis of coreactant-type analytes is often based on the calibration curve, namely a graph generated by plotting the measured light intensity of a series of standard solutions against their concentrations, the contribution of “catalytic route” particularly at a low concentration of analyte (equivalent to a relatively large c Ru / c TPrA ) is favorable to the analytical sensitivity. Moreover, the presence and absence of this route will result in a nonlinear and linear calibration curve, respectively, for example in the detection of TPrA and pyruvate. The results highlight the microwire-based imaging approach can provide insightful mechanistic information and help unveil the concentration dependence of measured ECL intensity for precise quantitative analysis.
研究领域:
分析化学
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电化学
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生物传感
✓ 已验证
DOI
Environmental Science-Nano
·
2017
·Vol. 4
·期 11
·2134-2143
·
IF 6.047
Chen Tian,Jian Zhao,Jing Zhang,Shengqi Chu,Zhi Dang,Zhang Lin,Baoshan Xing
Roxarsone (ROX) is an emerging arsenic pollutant due to its potential degradation into highly toxic inorganic arsenic species in the environment. Adsorbents which can capture ROX with both high capacity and affinity are urgently needed. Herein, a nanocomposite of nano-Fe3O4 and three-dimensional graphene (Fe3O4@RGO) was designed, aiming to simultaneously attract arsenate and benzene groups in ROX. Characterization of the nanocomposite revealed that Fe3O4 nanoparticles (20–50 nm) with exposed (400) planes were highly dispersed on the graphene support. Adsorption experiments showed that Fe3O4@RGO had higher adsorption capacity, affinity, and adsorption rate towards ROX than pristine materials and efficiently removed ROX from both simulated natural and waste waters. The adsorption mechanism was confirmed as a synergetic interaction of As–Fe coordination, hydrogen bonding and π–π interaction. X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS) results suggested that the As–Fe complexes and hydrogen bonds between Fe3O4@RGO and ROX were stronger than those in pristine nano-Fe3O4, due to the greater number of surface hydroxyls and shorter As–Fe atomic distance in Fe3O4@RGO. The π–π interaction between ROX and the graphene part in Fe3O4@RGO was also enhanced. This study provided a novel idea for designing materials to remove pollutants with both inorganic and organic moieties, such as phenylarsonic acid compounds, from water.
研究领域:
环境科学
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材料化学
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水污染控制
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纳米技术
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分析化学
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2015
·Vol. 17
·期 8
·1805-1812
·
IF 4.034
Jingmiao Peng,Ying Zhou,Hao Wang,Haoran Zhou,Shiyi Cai
Strontium titanate (SrTiO3) nanocrystals have been synthesized by a hydrothermal reaction route using anatase TiO2 nanosheets with dominant {001} facets and commercial anatase TiO2 nanoparticles as precursors. Time-resolved quenching experiments showed that the speed of hydrothermal formation of SrTiO3 was relatively fast (in minutes). The initial particle morphology and exposed crystal facets of anatase TiO2 precursor cannot be retained in the final SrTiO3 products. SrTiO3 nuclei are formed by the reaction between Ti(OH)x4−x and Sr ions at the TiO2 solid/liquid interface. As surface adsorbed F− is necessary to stabilize the {001} facets of anatase TiO2, the hydrothermal crystallization of SrTiO3 from TiO2 with {001} facets not only exhibits a slower reaction rate but also a higher activation energy. Moreover, the photoelectrochemical and photocatalytic activity studies indicated that the SrTiO3 products obtained from TiO2 with {001} facets showed enhanced photocurrent density and photocatalytic hydrogen production activity. The present study sheds some light on the understanding of the crystal facets of the precursor on the hydrothermal formation process as well as the photocatalytic activities of the corresponding products.
研究领域:
材料科学
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纳米技术
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光催化
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无机化学
·
能源材料
✓ 已验证
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2024
·
IF 6.3
Bo Xu,Meng Jia,Dong Wang,Siheng Zhao,Shouao Zhu,Lijun Qian
Four polyphosphate/polyphosphonate flame retardants (PAP, POP, PAP-UB and POP-UB) have been designed and synthesized to study the effects of phosphorus valence states and the presence of unsaturated carbon-carbon double bonds on self-cross-linking impacting flame-retardant modes of action. It was found that phosphorus valence states affect the proportion of flame-retardant activity between the gas phase and condensed phase. A phosphonate containing +3-valence phosphorus is primarily effective as a gas-phase flame-retardant, while the one containing +5-valence phosphorus mainly exerted an impact in the condensed phase. The introduction of an unsaturated bond enhances the carbon-forming effect promoted by polyphosphates/polyphosphonates in a degrading polymer matrix and increases the melt viscosity for blends at high temperature. The phosphorus-containing fragments which might have been released into the gas phase are locked in the condensed phase due to C C bonds cross-linking, thus forming more high-quality phosphorus-rich char layers. This effect balances the distribution of gas-phase and condense-phase flame-retardant effects and is especially obvious in PET/polyphosphonate blends containing +3-valence phosphorus, which originally plays mainly the role of a gas-phase flame retardant . PET blends containing unsaturated carbon-carbon double bonds display better carbon formation, flame-retardant activity and anti-dripping behavior than these do without this feature.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY
·
2017
·Vol. 90
·期 1
·149-155
·
IF 1.095
Dong Peng,Li Zeyu,Ji Dong,Wang Xiaorui,Yun Hongfei,Du Zhisong,Bian Jie,Li Guixian
Modified Y type catalyst (M-Y) shows great potential for the preparation of toluene attribute to catalyst topology and synergistic effect of Lewis acid and Brönsted acid in the alkylation reaction. However, it still remains a big challenge to build a reaction mechanism. Thereby, based on the study of HZSM-5, H-beta and M-Y catalysts structure and physical properties, a plausible reaction mechanism was proposed. The samples were characterized by X-ray diffraction, N 2 adsorption/desorption, Fourier transform infrared absorption spectra and Pyridine adsorption infrared. The activity of catalysts was tested in benzene alkylation with methanol and was found to be in the following increasing order: Na-Y (no effect) < H-Y << HZSM-5 < H-beta < M-Y.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 7
·5287-5292
·
IF 2.324
Cao Renping,Quan Guanjun,Shi Zhihui,Gou Qingdong,Chen Ting,Hu Zuofu,Luo Zhiyang
Novel LiBaPO 4 :Bi 3+ yellow-emitting phosphor is synthesized by high temperature solid-state reaction method in air. With excitation 260 nm, LiBaPO 4 :Bi 3+ phosphor emits yellow light with the chromaticity coordinate (0.4272, 0.4657) and color rendering index 77.7. Emission band peaking at ~ 588 nm of LiBaPO 4 :Bi 3+ phosphor in the range of 400–790 nm is attributed to the 3 P 1 → 1 S 0 electron transition of Bi 3+ ion. Excitation band monitored at 588 nm in the range of 220–300 nm is assigned to the 1 S 0 → 3 P 1 electron transition of Bi 3+ ion. The optimal Bi 3+ ion concentration in LiBaPO 4 :Bi 3+ phosphor is ~ 1.0 mol%. Time resolved spectra and fluorescence lifetime data confirm that there is only Bi 3+ ion luminous center in LiBaPO 4 :Bi 3+ phosphor. The luminous mechanism is analyzed by configurational coordinate diagram of Bi 3+ ion. The experiment results are helpful to develop other new Bi 3+ -doped optical materials for solid-state lighting.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2019
·
IF 4.12
Dong-Xu Tian,Yue-Xi Liu,Bing-Yin Wang,Chuang-Chuang Cao,Zhong-Kai Liu,Yi-Tong Zhai,Yan Zhang,Jiu-Zhong Yang,Zhen-Yu Tian
Pyrolysis study of iso-propylbenzene (IPB) at 30 and 760 torr was carried out by using synchrotron photoionization and molecular beam mass spectrometry techniques. 0.5%IPB was diluted by helium and heated to 798–1148 K in a flow tube. Styrene was the most abundant aromatic intermediate at both pressures. Several polycyclic aromatics were only observed at 760 torr, such as 2-ethenyl-1, 4-dimethyl-benzene, fluorene, anthracene , phenanthrene, 2-methyl-anthracene and pyrene, while fulvene, 1, 3-cyclohexadiene, and 5-ethenylidene-1, 3-cyclopentadiene were only detected at 30 torr. A detail mechanism involving 306 species and 1990 reactions was developed by updating ipso-addition and unimolecular dissociation reactions of IPB as well as reactions related to styrene, indene and naphthalene . The mechanism could predict the pyrolysis of IPB and production of other intermediates well. Rate-of-production analysis shows that the formations of 2-phenethyl, 1-iso-phenylpropyl and 2-iso-phenylpropyl radicals are the main consumption reactions of IPB independent of pressure. Sensitivity analysis indicates that the unimolecular dissociation of IPB forming 2-phenethyl radical is the most significant promoting reaction at both pressures. H-abstraction reaction forming 1-iso-phenylpropyl radical tends to play a significant inhibiting effect on IPB consumption at 30 torr, while the most inhibiting reaction is self-combination of methyl radicals at 760 torr. Compared to n-propylbenzene experiments reported by Liu et al. (Combustion and Flame, 191 (2018) 53–65) and Yuan et al. (Combustion and Flame,186 (2017) 178–192.), IPB tends to produce larger quantities of benzene, styrene and indene under pyrolysis and oxidation conditions. These results will improve the understanding of the combustion and soot formation of IPB as a potential aviation surrogate fuel.
研究领域:
化学动力学
·
燃烧科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Bogu Liu,Bao Zhang,Ying Wu,Wei Lv,Shixue Zhou
Transition metals, including Ni, show good catalytic activity in the hydrogen storage reaction of Mg. In the present paper, first-principles calculation is performed to predict and analyze the hydriding reaction of Ni-incorporated Mg and experimental study is used to verify the accuracy of the forecast. Theoretical studies show that the hydriding reaction of Ni-incorporated Mg is a diffusion-controlled process. With Ni incorporation, the energy barrier of H 2 dissociation is significantly decreased and the diffusion becomes the limiting step. Experimental studies confirm the results of theoretical studies. Besides, the material with Ni incorporation shows excellent activation performance and rapid absorption rates, leading to a high hydrogen content of 4.1 wt% in 60 s under 240 °C 3.0 MPa H 2 and a low activation energy of 56.1 kJ mol −1 versus 0.4 wt% and 73.5 kJ mol −1 for the material without Ni incorporation. Atomic Ni only plays a role of catalyst.
研究领域:
材料科学
·
物理化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2020
·
IF 5.006
Haodong Duan,Xiaolei Xu,Kangwei Leng,Ge Guo,Qing Yu,Xinjin Li,Yuxi Han,Jun Gao,Zhongwei Wang
The characteristics of the reaction for the preparation of dichlorophenylphosphine (DCPP) via benzene and PCl 3 in the presence of AlCl 3 were studied. Some unique characteristics were observed when a catalytic amount of AlCl 3 was used. Namely, more than one mole of DCPP was obtained per mole AlCl 3 , the reaction solution was layered, and DCPP could be directly separated. Our mechanistic study showed that benzene reacted with PCl 3 to form DCPP-AlCl 3 , and DCPP-AlCl 3 dissociated into DCPP and AlCl 3 , continuing to catalyze this reaction. This resulted in the high catalytic efficiency of AlCl 3 . The layering of the reaction solution was caused by the immiscibility of DCPP-AlCl 3 with the raw materials, greatly facilitating the dissociation process of DCPP-AlCl 3 . The formation of diphenylphosphorus chloride (DPC) was due to a continuous Friedel-Crafts reaction between DCPP and benzene. DPC cooperated with AlCl 3 to form the stable coordination compound DPC-AlCl 3 that did not dissociate and was responsible for the deactivation of AlCl 3 .
研究领域:
有机化学
·
催化化学
✓ 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）