NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 30
·13329-13339
·
IF 3.591
Dong Wang,Yang Wang,Xuhui Zhang,Ting Li,Mingliang Du,Mingqing Chen,Weifu Dong
Bio-based flame retardants (FRs) have drawn increasing attention for FR polylactide (PLA). Hence, a green and facile method was presented in this work for the synthesis of melamine phytate (MPA), melamine copper phytate (MPACu), melamine zinc phytate (MPAZn), and melamine magnesium phytate (MPAMg). In general, the PLA/MPAZn composite exhibited a better flame retardancy and smoke suppression with an acceptable mechanical property. With the addition of 20 phr MPAZn, the peak of heat release rate (PHRR) was decreased by 45.0% compared with that of neat PLA. Also, TSR of the PLA/MPAZn composite was the lowest among the FR PLA composites in this study. Furthermore, the higher quality char residues played the key role in the synergistic flame retardancy and smoke suppression for the PLA/MPAZn composites. In addition, in this work, we found that the mass loss rate (MLR) was highly related to the heat release rate (HRR).
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2017
·Vol. 7
·期 8
·1776-1791
·
IF 5.773
Yanming Jia,Junwen Wang,Kan Zhang,Shibin Liu,Guoliang Chen,Yufei Yang,Chuanmin Ding,Ping Liu
ZnSiF6-modified nano-sized HZSM-5 zeolites (NZ2, NZ3 and NZ4 catalysts) were prepared and investigated as catalysts for the conversion of methanol to aromatics. Moreover, the ZnNZ1 catalyst, prepared by ion exchange using zinc nitrate, was also introduced as a reference sample. The effects of modification on the framework, textural properties and acidity of the parent nano-sized HZSM-5 zeolite (NZ1) were investigated by XRD, FT-IR, 29Si MAS-NMR, SEM, N2 adsorption–desorption, ICP, NH3-TPD, infrared spectroscopy of adsorbed pyridine (Py-IR), UV-vis spectra, X-ray photoelectron spectroscopy (XPS) and n-butylamine and tert-butylamine titration. The results showed that the amount of total acid sites, especially the external surface acid sites of the NZ2, NZ3 and NZ4 catalysts, significantly decreased, which may largely be attributed to the passivation effect of SiF62− on the surface acidity of the parent NZ1 catalyst. Moreover, the amount of Lewis acid sites (L acid sites) increased, whereas the amount of Brønsted acid sites (B acid sites) obviously decreased with the introduction of zinc species. The emergence of new Zn-Lewis acid sites (⊖ZO⋯H⋯O–Zn⊕ species) was beneficial to improving the selectivity to BTX (benzene (B), toluene (T) and xylene (X)) due to their high activity for dehydroaromatization. The FT-IR spectra in the OH− vibration region and the 29Si MAS-NMR spectra show that the treatment of ZnSiF6 could effectively repair partial lattice defects of zeolite and could thus improve the catalyst stability. TG analysis of all the deactivated catalysts showed that the coke amount and the average rate of coke formation decreased over NZ2, NZ3 and NZ4 catalysts, and this may largely be ascribed to their lower surface acidity. The catalytic performance of these materials on the conversion of methanol to aromatics showed that the NZ3 catalyst had the highest selectivity to BTX of about 51.3% and the longest catalytic lifetime of about 234 h under the operating conditions of T = 425 °C, p = 0.1 MPa and WHSV = 0.8 h−1. The improvement in the selectivity to BTX and the catalyst lifetime of the NZ3 catalyst could be ascribed to the synergistic effect among the Zn-Lewis acid sites (⊖ZO⋯H⋯O–Zn⊕ species), external surface acidity and intact framework structure.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
·
2022
·
IF 4.654
Jun Zhang,Zhen Wu,Yafei Wu,Xiaoling Liu,Xun Li,Yu Zhang,Haian Xia,Fei Wang
Catalytic cracking of fatty acid methyl esters (biodiesel) is an attractive alternative to petroleum processing to produce valuable and versatile aromatics over the Zn-modified HZSM-5(25) catalysts. The catalysts with a Zn loading amount of 0–2.6 wt % were prepared and characterized. The introduction of Zn species presented great effects on the textural property and acidity of the parent HZSM-5(25) zeolite, and the chemical state of Zn species was heavily dependent on the amount of Zn loading. The strong Brönsted acid sites on the 0.5% Zn/HZSM-5(25) catalyst were exchanged by Zn species and formed new Zn-Lewis acid sites, which were identified as [ZnOH]+ and Zn2+ species. These Zn species greatly enhanced the dehydrogenation activation of alkanes to form more alkenes. Besides, they also promoted the further dehydrogenation reactions during aromatization of alkenes, thus improving the formation of H2 (>4 wt %) and increasing the production of aromatics (>40 wt %). The dominant components in the organic liquid product were monocyclic aromatics including benzene, toluene, and xylenes. Moreover, the 0.5% Zn/HZSM-5(25) catalyst exhibited an excellent stability, adaptability, and regeneration.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
Advances in Materials Science and Engineering
·
2022
·Vol. 2022
·期 1
·7408284
·
IF 2.098
Zhenhao Wei,Yufan Ji,Yiping Huang,Jingjing Huang,Yunguo Huang,Changhai Yue,Junzhou Li,Mingwei Tang,Yunfang Liu,Hanfei Liu,Hao Zhu,Kai Zhu,Fan Yang,Xuedong Zhu
Zinc (Zn) and cerium (Ce) modified hierarchical ZSM-5 (HZ) catalysts were prepared by incipient wetness impregnation, and their catalytic performances in methanol to aromatics reaction were evaluated in a fixed-bed reactor operating at 400°C under 0.1 MPa and WHSV of 1.0 h −1 . The structure, acidity, and state of Zn species of the Zn/Ce modified HZ catalysts were investigated via several characterization techniques, including XRD, NH 3 -TPD, H 2 -TPR, nitrogen adsorption, and XPS. The results showed that the aromatization activity of 2 wt% Zn-modified HZ (2% Zn/HZ) could be significantly enhanced by loading 0.6 wt% Ce, which was mainly attributed to the increase in surface ZnOH + species. Moreover, it was found that Ce inhibited pore blockage caused by Zn. Consequently, compared to 2% Zn/HZ, 2% Zn-0.6% Ce/HZ exhibited higher aromatic selectivity and longer catalyst lifetime.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Jian Zhang,Liang Wang,Zhiyi Wu,Hai Wang,Chengtao Wang,Shichao Han,Feng-Shou Xiao
We report the synthesis of Zn/ZSM-5 particles coated with a silicalite-1 zeolite shell (core–shell Zn/ZSM-5@silicalite-1) via grinding of the raw silica source materials with TPAOH and Zn/ZSM-5, followed by solvent-free crystallization at 180 °C for 72 h. The product was well characterized by the XRD patterns, N2 sorption isotherms, SEM images, and TEM images. Because of the core–shell structure, the Zn/ZSM-5@silicalite-1 sample exhibits high selectivities for benzene, toluene, and xylenes in the conversion of methanol, compared with those over ZSM-5 and Zn/ZSM-5 samples. The solvent-free synthesis offers an alternative method for preparing core–shell Zn/ZSM-5@silicalite-1 catalysts.
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
Journal of Energy Chemistry
·
2015
·
IF 2.352
Xiaodong Wang,Xiaoxia Gao,Mei Dong,Hongbin Zhao,Wei Huang
Nano hierarchical mesoporous ZSM-5 catalysts were prepared with cationic dimethyldiallyl ammonium chloride acrylamide copolymer (PDDA) as a soft second template. Using ZSM-5 catalyst as a matrix, Zn/ZSM-5 catalysts were also obtained by the wet impregnation method. The effect of the PDDA amount and Zn loadings on the properties of the catalysts, including crystallinity , morphology, textural properties, acid nature and catalytic activity in MTG reaction, was investigated by XRD , FESEM , TEM, Nitrogen adsorption–desorption isotherms and NH 3 -TPD method, respectively. The MTG reaction was performed in a fixed bed reactor , and the result revealed that the nano hierarchical ZSM-5 catalyst prepared with a PDDA/Si molar ratio of 0.070 possesses longer stable phase of 70 h with a liquid hydrocarbon selectivity of 29.8%. Zn/ZSM-5 catalyst with a Zn/ZSM-5 ratio of 0.07 wt.% shows the highest liquid hydrocarbon selectivity, reaching 62.5%.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2024
·
IF 5.3
Lei Cai,Xiu Gao,Peihang He,Beining Luo,Xianzai Yan,Zedong Zhang,Wenjun Wang,Guoqiang Wu
To improve the catalytic epoxidation activity of conventional TS-1 zeolite under acid-free conditions, a series of TS-1-supported zinc ( x Zn/TS-1) catalysts were prepared and evaluated in the epoxidation of 1-hexene and methyl oleate (MO) with H 2 O 2 oxidant. The microstructure of x Zn/TS-1 was investigated using various characterization techniques, and the results showed that the introduction of Zn species was not only well dispersed on the surface of TS-1 but also did not disrupt the crystal structure of TS-1 and tetrahedral framework titanium. Furthermore, the Ti-O-Zn structure can be formed between Zn and Ti species through O-atomic coordination, which improves the vulnerability of the Ti-O bond to attack the H 2 O 2 molecule, and ultimately facilitates the epoxidation reaction between 1-hexene and MO. In addition, the 2% Zn/TS-1 catalysts showed optimal conversions of 45.7 % and 75.41 % for 1-hexene and MO, respectively, and exhibited good catalytic stability and regeneration during the epoxidation process.
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
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2025
·
IF 1.9
Yu-cheng Jiang,Bao-guang Zhu,Xiang-li Long
The oxidation of 1-(4-chlorophenyl)-pyrazolidin-3-one to 1-(4-chlorophenyl)-1H- pyrazol-3-ol by air can be accelerated by the Co(II)@AC catalyst prepared by loading Co(II) on activated carbon with wet impregnation method. ZnCl 2 solution has been used to treat activated carbon to ameliorate the catalytic ability of Co(II)@AC catalyst. The experiments indicate that the optimal catalyst is made by immersing activated carbon in 0.7 mol/L ZnCl 2 solution at 50°C for 6 h with a liquid/solid ratio of 30/1 (mL/g) followed being calcined at 700°C for 5 h at a heating rate of 5°C/min under N 2 protection. The 1-(4-chlorophenyl)-1H-pyrazol-3-ol concentration catalyzed by the catalyst loaded on the best carbon reaches 0.01953 kg/L, which is 27.56% higher than that catalyzed by the catalyst loaded on the original carbon. The characterization results manifest that the modification with ZnCl 2 enriches the porous structure and increases the acidic groups on the surface of activated carbon. The conversion of 1-(4-chlorophenyl)-pyrazolidin-3-one is mainly determined by the physical structure of the activated carbon while the selectivity to 1-(4-chlorophenyl)-1H- pyrazol-3-ol is largely affected by the chemical characteristics of the activated carbon.
研究领域:
化学
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2022
·
IF 4.654
Shuowen Wang,Yunfeng Bao,Yu Qi,Hai Zou,Shiwen Du,Xueshang Xin,Nengcong Yang,Chun Yang,Qing-lun Wang,Fuxiang Zhang
With a superior light-response ability and a high dielectric constant, the perovskite oxynitride SrNbO2N was expected to be an efficient photocatalyst for solar water splitting. However, a high defect density that formed during its preparation process had inhibited its charge separation and decreased the photocatalytic activity. In this work, SrNbO2N was modified through a high concentration doping of Zn2+ at the B site to inhibit its defect formation and promote its photocatalytic oxygen evolution performance. The defect formation in Sr(Nb2/3Zn1/3)O3–xNy (SNZON) is inhibited due to the sacrificial reduction of zinc ions during the nitridation process. Benefiting from the successful inhibition of defect formation and the promoted surface hydrophobicity, a remarkably promoted water oxidation activity was achieved on the as-obtained SNZON photocatalyst and the apparent quantum efficiency at 420 ± 10 nm reaches about 2.4%. This work may endow a new solution toward the preparation of low-defect oxynitride semiconductors with enhanced solar to chemical energy conversion efficiency.
研究领域:
材料科学
·
光催化
·
太阳能转换
·
半导体物理
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMISTRY
·
2017
·Vol. 36
·期 3
·187-193
·
IF 1.852
Qing-Ning Zhao,Qing-Wen Song,Ping Liu,Qian-Xia Zhang,Jun-Hua Gao,Kan Zhang
The production of fine chemicals using CO 2 as C 1 building block through inexpensive heterogeneous catalysts with high efficiency under low pressure is challenging. Herein we propose for the first time the utilization of a multifunctional heterogeneous zinc-modified HZSM-5 (ZnHZSM-5) catalyst for upgrading CO 2 by incorporation into cyclic carbonates from CO 2 and epoxides. Owing to the nice surface properties such as abundant Lewis acid, Brønsted acid and Lewis base sites, large surface area, and plenty of micropores, CO 2 could be concentrated and well activated in ZnHZSM-5 verified by CO 2 -TPD, TG-MS, etc . Meanwhile, the epoxides were also activated through metal center and hydrogen bond. Therefore, the reaction can easily assemble at the catalyst interface and show exceptional performance, affording the aimed products with high yield of up to 99% in the presence of commercial tetra- n -propylammonium bromide (90% in kilogram scale with 0.004 mol% ZnHZSM-5 and 0.015 mol% n Pr 4 NBr).
研究领域:
催化化学
·
环境化学
·
绿色化学
·
材料化学
·
有机合成
·
能源化学
·
工业化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）