CHINESE JOURNAL OF CHEMISTRY
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2021
·Vol. 40
·期 8
·918-924
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IF 6
Jisheng Xu,Chengxiang Shi,Shuguang Zhang,Qiancheng Zheng,Lun Pan,Xiangwen Zhang,Ji-Jun Zou
Comprehensive Summary Non-oxidative ethane dehydrogenation is a promising route to produce ethene. Herein, PtSn supported catalysts were investigated to achieve better ethane dehydrogenation performance by introduction of different Zr promoters, i.e. , framework Zr and ZrO 2 , to mesoporous MCM-41. In-situ XRD, TEM and CO chemisorption show that aggregation of metal particles and phase segregation of Pt 3 Sn to Pt and PtSn 3 at high temperature occur for PtSn/M, leading to bad ethane dehydrogenation activity. Strong interaction between ZrO 2 and PtSn species, as proved by XPS, results in restrained metal particles, which promotes the initial reactivity. However, Pt phase generated on surface is disadvantageous for the desorption of produced ethene as indicated by CO-IR and C 3 H 6 -TPD, and pyridine-IR and NH 3 -TPD indicate strong acidity generated. Both deactivate the catalyst rapidly by deep dehydrogenation and coking. Moderate interaction between PtSn species and Si-O-Zr with much weaker acidity is formed when framework Zr is incorporated into MCM-41, which benefits the dispersion of metal particles, formation of Pt 3 Sn/Pt species and stabilization of metal species from phase segregation. Outstanding initial ethane conversion and ethene selectivity of ca. 99% were achieved for the optimal PtSn/ZrM, which is more coking-tolerant and stable by generating graphitic carbon mainly on support instead of active metals.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
CATALYSIS COMMUNICATIONS
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2018
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IF 3.463
Qinqin Wang,Mingyuan Zhu,Haiyang Zhang,Caixia Xu,Bin Dai,Jinli Zhang
Zr-modified ZSM-5 zeolite was successfully prepared, and Zn/Zr-ZSM-5 was employed as a catalyst for the acetylene hydration reaction. High catalytic activity, above 96% C 2 H 2 conversion, was achieved at 260 °C with a feed reactant ratio of H 2 O/C 2 H 4 = 4 and a GHSV of 90 h −1 . To understand the influence of zirconium addition in the zeolite, Fourier-transform infrared spectroscopy, X-ray diffraction, surface texture analysis (BET method), transmission electron microscopy, temperature programmed desorption of NH 3 , temperature programmed reduction by hydrogen and X-ray photoelectron spectroscopy techniques were used. The incorporation of zirconium in the zeolite enhanced Zn metal dispersion and metal–support interactions. Moreover, an enhanced concentration of weak acid sites and active catalytic sites were found to be responsible for the high catalytic activity of Zn/Zr-ZSM-5 for the acetylene hydration.
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 the Australian Ceramic Society
·
2024
·
IF 1.8
Lin Jia,Wang Shuai,Yang Yihang,Huang Guimei,Wang Jinhuo
In this study, Zr-modified Si-O-C precursor ceramics were prepared using three-dimensional (3D) printing. Ceramic sintering was completed by printing four precursors containing different zirconium acetylacetone contents. Comparative analysis was conducted on the ceramic yield, size shrinkage, mechanical properties, and microstructure. The results showed that the ceramic yield and size shrinkage of the four samples were increased with the increasing zirconium acetylacetone contents. The sample containing 30 wt% zirconium acetylacetone exhibited good compressive performance, with a compressive strength of 50.2 ± 0.6 MPa. Cracks were observed on the surface of samples containing 40 wt% zirconium acetylacetone, while those containing 10, 20, and 30 wt% zirconium acetylacetone were relatively intact. Therefore, a stable Si-Zr-O-C precursor ceramic with good mechanical properties, which can be used for 3D printing, was obtained.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2020
·
IF 4.748
Mei Zhong,Da Zou,Yuebing Xu,Lijun Jin,Yue Pan
Acid treated kaolinites (KA) were successively loaded with Zr and Fe, Ni or Co component to control the product distribution and upgrade the tar quality in coal pyrolysis . The structure of the resultant catalysts was characterized and their catalytic performance in the pyrolysis of demineralized low-rank coal and benzyl phenyl ether (BPE), a model compound containing C al -O bridge bond, were investigated. Results show that the introducing of Zr into the KA can enlarge the hysteresis loop due to the stacking of ZrO 2 particles. The acidities, especially the strong ones, increase as the Zr content is below 8 wt% (KA-8Z). When adding Fe, Ni or Co metals into the KA-8Z, the number of Brønsted acid sites obviously decreases, but Lewis acid sites increase. The maximum BPE conversion of 94.0% occurs for the KA-8Z, further metal-loaded sample promotes the cleavage of C al -O bond in BPE and the formation of active H radicals from CH 3 OH, leading to the increase of BPE conversion. Besides, remarkable enhancement of target monomeric aromatics is observed for the Fe, Ni and Co-loaded samples. Compared with the pyrolysis without catalyst, the tar yield as well as pitch content decrease over the KA-8Z and its metal-modified catalysts. Wherein, Ni-KA-8Z has the highest activity for tar upgrading, leading to the largest increase in the contents of light oil and phenol oil. In-situ pyrolysis by time-of-flight mass spectrometry reveals the enhanced dissociation of weak covalent bonds linked in the coal skeleton over the KA-8Z and Fe, Ni and Co-modified catalysts, resulting in a decrease in the peak temperature for product release. A marked increase in phenols and diphenols confirms a promoted dissociation of ether bond in coal.
研究领域:
化学工程
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能源科学
✓ 已验证
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2020
·Vol. 7
·期 14
·2629-2636
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IF 5.958
Guoan Lin,Ran Wang,Tongcheng Cao,Liangxi Yuan,Xiaoxiang Xu
With an absorption edge as far as 690 nm, SrNbO2N holds great promise for solar energy conversion. However, very poor photocatalytic activity is generally seen for SrNbO2N, limiting its practical applications as a photocatalyst. In this work, SrNbO2N is modified by introducing Zr at B sites, i.e. SrNb1−xZrxO2+yN1−y (0 ≤ x ≤ 1), which are then investigated as photocatalysts for water oxidation reactions. Zr modification not only induces porous microstructures and inhibits the formation of Nb4+ defects, but it also ameliorates the surface hydrophilicity of SrNbO2N. Clear improvements in photocatalytic water oxidation have been realized after Zr modification and an apparent quantum efficiency of as high as 1.44% has been achieved. Further analysis of the band edge alignments suggests that Zr modification positively shifts the valence band edge of SrNbO2N, which favors water oxidation reactions.
研究领域:
材料科学
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光催化
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太阳能转换
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 30
·21799-21807
·
IF 3.9
Yijin Sheng,Fangxu Hu,Yu Wu,De Li,Wenting Ji,Yong Chen
The electrochemical oscillation in Li-ion batteries has been reported for two-phase electrode materials of Li4Ti5O12 and LiCrTiO4, which is originated from the group-by-group phase transition in a multi-particle electrode. For both Li4Ti5O12 and LiCrTiO4, the electrochemical oscillation exhibits usually during charging, while rarely for discharging. Herein, a series of Zr-modified Li4Ti5O12 samples are prepared by using the spray-drying combined with high-temperature sintering method, and the electrochemical oscillation is observed during not only the charging process, but also the discharging process, which gradually grows up and then disappears by increasing the Li content. Compared with Li4Ti5O12, the specific capacity of Zr-modified Li4Ti5O12 decreases gradually by increasing the Zr/Ti ratio, owing to the impurity phases. According to the XRD, XPS and STEM results, the Zr element tends to accumulate on the surface to form ZrO2 nanoparticles, rather than dope into the bulk phase of Li4Ti5O12, which makes Li4Ti5O12 particles well dispersive. In contrast to the Li deficiency for only charging, the electrochemical oscillation during both charging and discharging should be attributed to the Li excess, but too much Li2TiO3 phase will suppress the electrochemical oscillation. Therefore, the Li excess can induce the electrochemical oscillation during both charging and discharging of Zr-modified Li4Ti5O12, which can be adopted to investigate the electrochemical oscillation of other materials in LIBs.
研究领域:
材料科学
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电化学
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电池技术
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纳米技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）