ChemCatChem
·
2016
·Vol. 8
·期 23
·3636-3643
·
IF 4.724
Zhenyou Gui,Wenrong Cao,Shunmugavel Saravanamurugan,Anders Riisager,Lifang Chen,Zhiwen Qi
Graphical Efficient noble alloy : Au–Pd supported on zinc hydroxycarbonate (ZOC) catalysts shows high activity for 5-hydroxymethylfurfural oxidation. The basicity of ZOC can play a crucial role in enhancing the yield of FDCA. Moreover, Au–Pd/ZOC can be recycled at least six times without significant loss of its activity. Bimetallic catalysts with Au–Pd supported on zinc hydroxycarbonate (ZOC) were synthesized by a simple deposition–precipitation method and analyzed by transmission electron microscopy to have a narrow-size distribution of predominantly 1–2 nm. The prepared Au–Pd/ZOC catalysts exhibited excellent activity towards 5-hydoxymethylfurfural (HMF) oxidation in water in the presence of the base NaHCO 3 at benign conditions of 80 °C and 3 bar O 2 , resulting in quantitative yield of 2,5-furandicarboxylic acid (FDCA). The addition of base not only enhanced the yield of FDCA but also stabilized the support ZOC by preventing ZOC from the reaction with formed carboxylic acid intermediates/products, thus allowing Au–Pd/ZOC to be recycled for at least six times without significant loss of activity. The basicity of ZOC could play an important role in obtaining the improved yield of FDCA as compared to other supports.
研究领域:
催化化学
·
绿色化学
·
化学工程
·
材料科学
·
有机合成
·
环境科学
✓ 已验证
DOI
高影响因子
ACTA MATERIALIA
·
2023
·
IF 9.4
Junyan Gao,Peng Liu,Jinshu Wang,Ruimin Zhang,Yunfei Yang,Wenyuan Zhou,Hexiong Liu,Junhao Sun
The size and distribution of Sc 2 O 3 in the composite powder precursor has great effect on the emission property of scandate cathode. By one-step in-situ synthesis method, the composite powder exhibits the structure of quasi-spherical Sc 2 O 3 nanoparticles grown in situ on the surface of W/Ir grains, and the obtained W–Ir cathode with 3wt % Sc 2 O 3 could provide the emission current density of 83.43 A/cm 2 at 900 °C b , which is higher than other W–Ir mixed matrix scandate cathodes and W matrix scandate cathode. The XRD results showed that the high emission ability depended on the high content of active phase α-Ba 2 ScAlO 5 and low content of non-active phase BaAl 2 O 4 . In-situ TEM has been applied to observe the microstructure evolution of the cathode surface at high temperature for the first time. A serial change in the microstructural features of cathode surface and the migration of Ba, Sc and O on the substrate surface has been found, confirming the formation of Ba-Sc-O active layer. The first-principles calculations indicate that the active substances (Sc) are more stable (low adsorption energy of − 8.58 eV) on the IrW matrix cathode surface than on the tungsten matrix cathode surface, which is consistent with the low evaporation rate of the active substance detected by TFMS technique. Besides, the interaction between the active substance and the matrix was strengthened due to more electron transfer of Sc (1.88 e) and Ba (1.45 e), therefore lowering the work function . The feasible preparation technique makes such a cathode promising for applications in high-power microwave devices.
研究领域:
材料科学
·
电子工程
·
表面科学
·
纳米技术
✓ 已验证
DOI
高影响因子
MACROMOLECULES
·
2025
·
IF 5.2
Meng Xie,Yan He,Rui Xue,Wenjie Fan,Menglu Li,Quan Sun,Jennifer Q. Lu,Zongbo Zhang,Wenxin Fu
Next-generation, high-frequency communication systems demand polymer nanocomposites with simultaneously ultralow dielectric constant (Dk < 2.0) and high thermomechanical stability while addressing the critical challenge of reconciling nanoscale dispersion uniformity with interfacial compatibility. Herein, we propose a molecular engineering strategy to covalently anchor oligomeric silsesquioxane domains within a benzocyclobutene resin (BCB) matrix via synergistic click chemistry and thermally triggered Diels–Alder cross-linking. The silsesquioxane precursors are precisely synthesized through platinum-catalyzed hydrosilylation and hydrolysis-polycondensation, enabling the formation of ladder/cage-like and networked Si–O–Si structures. This covalent integration strategy ensures uniform silsesquioxane dispersion at the subnanoscale, as evidenced by small-angle X-ray scattering (SAXS) and high-resolution transmission electron microscopy (TEM). The optimized nanocomposite exhibits an ultralow dielectric constant (Dk = 1.78) and loss (Df = 2.73 × 10–3) at 1.15 kHz, outperforming most reported BCB hybrids. This work establishes a molecular-scale engineering paradigm for low-Dk materials, offering transformative potential in 5G/6G communications and high-density integrated circuit technologies.
研究领域:
材料科学
·
聚合物纳米复合材料
·
介电材料
·
电子封装
·
高频通信系统
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Faqiang Shi,Zhonghua Li,Limeng Liu,Jiandong Wu,Jinfu Ma,Yujin Wang
In previous works, it was found hard to synthesize “phase pure” ζ-Ta 4 C 3-z at relatively low temperatures even by prolonged heating, though ζ-Ta 4 C 3-z was believed stable till decomposition at ~2130°C. When the samples were subjected to TEM , vast richness of locally disordered structures in close relation with stacking of the close-pacted Ta-atom planes was observed. Although kinetic factors including diffusion of C atoms/vacancies and re-stacking of the Ta-atom planes explain the densely disordered structures, the richness of local disorders is a scenario that shows cohabitant of the cubic, rhombohedral, and hexagonal structures in a single grain, i.e. formation of a “hybrid grain” consisted of the three symmetries, indicating a transitional or intermediate stage before complete formation of the final phase of rhombohedral ζ-Ta 4 C 3-z . This time tantalum carbide ceramics TaC x with C:Ta atomic ratios x = 0.66 and 0.7 were prepared by reaction hot pressing of TaC and Ta powder mixtures. 5–30 mol% Cu/Ag additives and heat treatments were used to reproduce “hybrid grains” to facilitate further TEM and HRTEM observations on the disordered hybrid grains to argue for the transitional/intermediate stage. The cohabitant cubic, rhombohedral, and hexagonal structures in single grains may also help explain the difficulty in identification of the various phases by XRD in the transitional/intermediate stage of ζ-Ta 4 C 3-z reaction. Microstructural evolution and fracture toughness of the composites were also investigated.
研究领域:
材料科学
·
陶瓷
·
纳米材料
·
固体化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Hengli Qian,Guanjie Yu,Qidong Hou,Yifan Nie,Chuanyunlong Bai,Xinyu Bai,Haozhi Wang,Meiting Ju
To achieve efficient degradation of pharmaceutical and personal care products (PPCPs), dual reaction centers [email protected] photo-Fenton catalysts with high-speed electron transmission channel were designed through surface hydroxyl-induced assembly. In [email protected] catalytic system, the photocatalysis center of ZnO and Fenton catalytic center of FePc were formed simultaneously. Concept and process for the control of hydroxyl groups to construct a dual reaction center [email protected] photo-Fenton catalyst were verified ingeniously based on the density functional theory (DFT) analysis and experimental results. A series of catalysts, including ZIF-8 (400 ℃-N 2 ), FePc (400 ℃-N 2 ), ZIF-8 (400 ℃)-FePc (400 ℃) and [email protected] were prepared and characterized by XRD, FTIR, TEM, BET, XPS, PL and DRS, respectively. The [email protected] catalyst showed superior performance for the photo-Fenton degradation of ibuprofen, affording degradation rate larger than 90 % within just 10 min under simulateed sunlight. The excellent performance of [email protected] catalyst is mainly attributed to the synergistic effect between dual reaction centers of [email protected] This work provides a novel method to construct dual reaction centers [email protected] catalyst with efficient photo-generated electrons transmission link and to strengthen the synergistic effect of dual reaction centers.
研究领域:
环境化学
·
催化
·
材料科学
·
光化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 15
·12467-12475
·
IF 2.22
Xie Xinxin,Wang Hui,Zhou Yanping,Huang Kama
Microwave-assisted reduction of graphene oxide (GO) has been reported to be very effective in producing high-quality reduced graphene oxide (rGO) and its composites. However, either pretreatment (e.g., heating) or an external trigger (e.g., copper wire) is required to initiate the process due to the poor microwave absorption ability of GO. In this work, we report a one-step self-triggered microwave-arcing approach for synthesizing rGO composites (NiCo/rGO) for the first time. Evidenced by permittivity value, the synergic microwave absorption between GO and the metal nitrate salts is found to play an important role in initiating the process. From XRD, Raman, XPS and TEM results, it is proposed that mildly reduced rGO is firstly formed after 10 s, which further enables stronger microwave absorption to facilitate the complete reduction of GO as well as formation of well-crystallized NiCo nanoparticles about 10 nm after 90 s. The as-synthesized product shows a minimum refection loss value of − 44.48 dB with an absorption bandwidth of 3.66 GHz at 4.5 mm.
研究领域:
材料科学
·
纳米技术
·
电磁材料
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
Journal of Inorganic and Organometallic Polymers and Materials
·
2019
·Vol. 29
·期 6
·2003-2011
·
IF 1.637
Hua Rui,Li He,Liu Xiao-Qin,Liu Ding-Hua
With an increasing demand for green chemistry and sustainable development, it is needed to design a solid base with high catalytic activity, excellent stability and reusability. In this work, a new kind of magnetic solid basic catalyst KF/CaO–CoFe 2 O 4 was prepared by the method including co-precipitation and isochoric impregnation, and it was successfully applied in the preparation of polycarbonate diol (PCDL) from the transesterification of 1,4-butanediol with dimethyl carbonate. The characteristics and properties of the catalyst were examined and analyzed by XRD, TEM, CO 2 -TPD and VSM. The effects of various parameters such as shell-core mole ratio, KF loading, calcination temperature, catalyst dosage, and the mole ratio of the raw materials on the yield of PCDL were investigated and the yield of PCDL can reach to 71.2% under the optimal reaction conditions. In addition, the catalyst can be easily separated by an external magnet after reaction, and the catalytic activity of the catalyst can well be maintained for 4 cycles.
研究领域:
化学工程
·
材料科学
·
催化
·
绿色化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Xiangzhan Meng,Yongqiang Zhang,Zengxi Li,Hui Wang,Suojiang Zhang
Au supported on monoclinic ZrO2 (Au/m-ZrO2) prepared by deposition–precipitation method showed excellent catalytic performance in the aerobic oxidation of amino alcohols to amino acids, i.e., glycine, alanine, serine, β-alanine, and 2-aminobutyric acid. The Au particle size and valence distribution of the gold species were adjusted by calcination temperature, as demonstrated by XRD, TEM, UV–vis DRS, XPS, and H2-TPR, which significantly influenced the catalytic activity but not the selectivity of amino acids. Metallic gold atoms on the surface were shown to be the active sites by the correlation between reaction rate per mole of metallic Au and Au particle size. The kinetics of oxidation of monoethanolamine (MEA) was studied in detail, and the results indicated that MEA oxidation is a first-order reaction with an activation energy of 52.8 kJ·mol–1.
研究领域:
催化
·
化学工程
·
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2015
·
IF 3.52
Haimei Xu,Zhichao Miao,Huahua Zhao,Jian Yang,Jun Zhao,Huanling Song,Ning Liang,Lingjun Chou
In this paper, a series of ordered mesoporous zirconium oxophosphate with different P/Zr molar ratios (M-ZrPO- x ) were prepared via one-pot evaporation induced self-assembly strategy (EISA). The catalytic performance of M-ZrPO- x for the dehydration reaction of fructose to produce 5-hydroxymethylfurfural (5-HMF) was also studied. With high concentration of Brönsted and Lewis acid sites measured through NH 3 -TPD and pyridine-IR, M-ZrPO-0.75 performed high catalytic activity (up to 97.4%) and selectivity (79.6%) of 5-HMF under relatively mild conditions. Furthermore, M-ZrPO-0.75 performed excellent catalytic stability. Based on detailed analyses of XRD, SEM, TEM, BET and XRF, the structural, surface and textural properties of M-ZrPO-0.75 after reaction were investigated. Obtained results demonstrated that the mesostructure still retained even after twelve cycles, which may be ascribed to the “ordered” mesoporous properties and high thermal stability. In addition, a lower activation energy was obtained in this M-ZrPO catalytic system using dimethyl sulfoxide as solvent.
研究领域:
化学工程
·
催化
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 24
·36337-36350
·
IF 5.19
Wang Bing,Cao Qingtong,Li Guomin,Zhang Jian
Given that the biological treatment of antibiotic wastewater can easily induce resistant bacteria, the photocatalytic degradation of antibiotics is considered as a better method for treating antibiotic wastewater. Therefore, the ability to remove Tylosin (TYL) and Tetracycline (TC) in aqueous solution using rare earth element Tb-doped g-C 3 N 4 under simulated natural solar radiation was investigated. A series of rare earth Tb 3+ doped mesoporous g-C 3 N 4 were successfully prepared by nitric acid treatment and Tb(NO 3 ) 3 ·5H 2 O samples showed significantly higher degradation efficiency for TYL and TC than pure g-C 3 N 4 . Leaching toxicity experiments were carried out on the catalyst using chard seeds and demonstrated negligible toxicity of the leachate from the catalyst. The structure, elemental state, optical properties, morphology, and photogenerated carrier separation of the prepared xTCN catalysts were characterized by XRD, XPS, UV–Vis DRS, TEM, and PL. The results show that Tb doping enhanced the photocatalytic activity of the g-C 3 N 4 catalyst by narrowing the band gap while improving the light-trapping ability; The separation and transport rate of photogenerated carriers were significantly increased after Tb doping. Finally, a simple, efficient, and non-polluting Tb-doped carbon nitride photocatalyst is successfully developed in this paper.
研究领域:
环境科学
·
材料科学
·
化学
·
光催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Zhengfeng Gu,Daiwei Liu,Mengnan Yu,Teng Bao,Xiaowei Liu,Ling Zhang,Haitao Ding,Zhimin Yu,Chengxun Deng
The synthesis of supported transition metal oxides with satisfactory low-temperature catalytic performance and application potential is still a challenge for the complete degradation of VOCs. Ni-Cu-loaded TiO 2 catalysts were prepared by an impregnation method. The lattice defect and oxygen vacancy concentrations of the prepared materials could be tuned by controlling the Ni/Cu molar ratio and the mass proportion of the TiO 2 support. 5Ni-Cu/TiO 2 exhibited the best catalytic activity and showed superior catalytic stability during complete toluene oxidation . The obtained catalysts were fully characterized by XRD, FT-IR, TEM, N 2 adsorption analysis, XPS, H 2 -TPR, O 2 -TPD, TPD analysis, and XPS. The 5Ni-Cu/TiO 2 catalyst had improved pore sizes and specific surface area, had more oxygen vacancies on its surface, had increased concentrations of adsorbed and lattice oxygen species, and had good redox properties; these characteristics were favorable for low-temperature catalytic performance and catalytic stability. Cyclic transformations of metal valence states between Cu + and Cu and between Ni and Ni 2+ were observed in the catalytic system. A potential catalytic reaction process based on the M-vK mechanism was proposed. This work serves as a reference for the application of supported transition metal catalysts for the degradation of VOCs.
研究领域:
催化
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2021
·Vol. 28
·期 6
·1737-1747
·
IF 2.496
Jiang Haoxi,Zhao Yingying,Lin Jing,Chen Yifei,Wang Sheng
Highly dispersed palladium nanoparticles (NPs) supported on UiO-66 as catalyst for CO 2 methanation were prepared by supercritical fluid deposition (SFD). As a result, the most suitable Pd precursor salt and co-solvent are Na 2 PdCl 4 and ethanol/DMF, respectively. The best SFD process condition to deposit the Pd precursor on UiO-66 is 40 °C, 10 MPa and 2 h. Under the above condition, 4% Pd/UiO-66 exhibits the highest activity with 53% of CO 2 conversion and 95% of CH 4 selectivity while the turnover frequency (TOF) value is 3669.4 h −1 . The catalysts were characterized by XRD, BET, TEM, XPS, TGA, CO-DRIFTS and ICP-OES to investigate the structure–activity relationship. The 4% Pd/UiO-66 with the average size of 2.2 nm of Pd prepared in assistance of supercritical fluid behaved the similar activity as the 6%Pd/UiO-66 with average size of 9.7 nm of Pd prepared by sol–gel method. It is showed prospect of technique for reducing noble metal loading resulting from high dispersion effect.
研究领域:
催化
·
材料科学
·
化学工程
·
环境科学
✓ 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）