CATALYSIS LETTERS
·
2018
·Vol. 148
·期 11
·3402-3412
·
IF 2.911
Bao Qiang,Qi Hui,Zhang Chunlei,Ning Chunli,Zhang Yi,Jiang Ye,Wu Yifan,Gui Wenying,Wang Zhenlu
Abstract In this work, titanium-doped mesoporous Al 2 O 3 (γ-Ti–Al 2 O 3 ) was prepared by an evaporation-induced self-assembly method and used as a carrier of Ba/γ-Ti–Al 2 O 3 catalyst to catalyze the aldol condensation of methyl acetate with formaldehyde to methyl acrylate in a fixed-bed reactor. The catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, N 2 adsorption–desorption, pyridine absorption performed via Fourier transform infrared spectroscope (Py-IR), and NH 3 and CO 2 temperature-programmed desorption (NH 3 and CO 2 -TPD). Experimental results indicated that the doping of the titanium species into the frame work of mesoporous Al 2 O 3 (γ-Ti–Al 2 O 3 ) had a significant influence on the catalytic activity via modifying the acid–base surface properties of the catalyst. Furthermore, the Ba/γ-Ti–Al 2 O 3 catalyst demonstrated excellent catalytic performance, with a methyl acetate conversion rate of 50% and methyl acrylate selectivity up to 90.2%. Compared with the Ba/Al 2 O 3 catalyst, the Ba/γ-Ti–Al 2 O 3 catalyst had better catalytic activity, stability and potential for practical application, which was likely due to an increased number of Lewis acid sites, especially the medium acid sites. Graphical Abstract Barium supported mesoporous γ-Ti–Al 2 O 3 catalyst was found to be an effective catalyst for vapor phase aldol condensation of methyl acetate with formaldehyde.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Tianqing Sheng,Shuqin Zhang,Xuguang Wei,Xinran Lv,Zhigang Yang
The porous Ti/perovskite composites were prepared successfully by ultrasound-assisted infiltration method. The Cs–Pb–Br perovskite materials were prepared on a larger scale by the mechanical ball-milling using the CsBr and PbBr 2 as the precursors. The Cs–Pb–Br perovskites had high PL intensity and excellent stability, meanwhile, the complex phase transformation between CsPbBr 3 and Cs 4 PbBr 6 occurred during the ball-milling process. The green fluorescence emission of composites might be attributed to CsPbBr 3 embedded within Cs 4 PbBr 6 perovskite. By the space occupying method, the porous Ti materials were prepared by using the acicular urea as the pore forming. The optimal young's modulus (1.0851 GPa) and porosity (38.27 %) were obtained. Finally, the prepared Ti/perovskite composites had outstanding fluorescence property and high stability, showing the wide application prospect in the fields of the bioflourescence imaging and nondestructive testing fields.
研究领域:
材料科学
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光学
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生物医学工程
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DOI
高影响因子
Materials
·
2019
·Vol. 12
·期 19
·3097
·
IF 2.972
Hailiang Du,Ning Tan,Li Fan,Jiajie Zhuang,Zhichao Qiu,Yanhua Lei
The diffusion coatings were deposited on commercially pure Ti and Ti-6Al-4V alloy at up to 1000 °C for up to 10 h using the pack cementation method. The pack powders consisted of 4 wt% Al (Al reservoir) and 4 wt% NH4Cl (activator) which were balanced with Al2O3(inert filler). The growth kinetics of coatings were gravimetrically measured by a high precision balance. The aluminised specimens were characterised by means of scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). At the early stages of deposition, a TiO2(rutile) scale, other than aluminide coating, was developed on both materials at <900 °C. As the experimental temperature arose above 900 °C, the rutile layer became unstable and reduced to the low oxidation state of Ti oxides. When the temperature increased to 1000 °C, the TiO2scale dissociated almost completely and the aluminide coating began to develop. After a triple-layered coating was generated, the coating growth was governed by the outward migration of Ti species from the substrates and obeyed the parabolic law. The coating formed consisted of an outer layer of Al3Ti, a mid-layer of Al2Ti and an inner layer of AlTi. The outer layer of Al3Ti dominated the thickness of the aluminide coating.Keywords:diffusion coating;aluminide;pack cementation;Ti;Ti-6Al-4V;mechanism
研究领域:
材料科学
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表面工程
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产品关联
DOI
PubMed
高影响因子
POLYHEDRON
·
2023
·
IF 2.6
Yadan Ma,Xuefen Jiang,Zhongmin Liu,Longlong Geng,Xiao lei Zhang,Ping Niu,Xiuling Zhang,Yongzheng Zhang,Dashuai Zhang,Hui Hu,Xin Li,Xiaoli Wang
Developing new adsorbents with hierarchical pore and unsaturated adsorption sites are highly demanded to achieve rapid adsorption rate and good adsorption selectivity in purifying organic wastewater. We here reported a new Quasi-MIL-125(Ti) synthesized at 340 °C under air atmosphere and considered as a high-efficiency adsorbent for capturing cationic dyes. The morphology of the material is characterized by XRD, SEM, TEM, etc. and the adsorption performance of Quasi-MIL-125(Ti) was systematically studied. Remarkably, it takes only 1 min to rapidly remove 20 mg L -1 MB or NR with 1 g L -1 Quasi-MIL-125(Ti), which is far superior to the previously reported materials. Adsorption isotherm shows that dyes adsorption on Quasi-MIL-125(Ti) follow a Langmuir adsorption isotherm model. The experimental maximum adsorption capacities were 109.3 mg g -1 for MB and 151.1 mg g -1 for NR, respectively. The hierarchical pores facilitate the diffusion and co-adsorption of different dye molecules. Adsorption mechanism reveals that the strong electrostatic attraction originated from the unsaturated Ti sites in Quasi-MIL-125(Ti) contributes to the ultra-fast adsorption behavior during cationic dyes chemisorption process. This study not only provides a promising prospect for the synthetic strategy of super-adsorbents, but also provides reference and theoretical guidance for practical dye wastewater treatment.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
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2025
·
IF 3.2
Liu Yang,Liang Kaili,Zhang Keqin,Du Bowen,Hu Lishuang,Yuan Zhilei,Zhang Jianren,Lu Yuewen,Yu Qi,Lv Zhixing
The output energy properties of the AP/Ti, Cl-20/Ti, HMX/Ti, and DAP-4/Ti mixtures were compared using an oxygen bomb calorimeter. The thermal decomposition processes of the above four kinds of mixed energetic materials were studied with a differential scanning calorimeter (DSC), and the apparent activation energies of the mixed materials were calculated using the Kissinger equation. The combustion flames of the four energetic materials were captured through high-speed photography, and the combustion properties of the mixed energetic materials with titanium powders were analyzed. The results indicate that the combustion heat value of DAP-4/Ti mixed energetic materials is up to 10,133 J·g −1 , significantly higher than the 8613 J·g −1 of the Cl-20/Ti mixture and the 9720 J·g −1 of the HMX/Ti mixture. The combustion process of the DAP-4/Ti mixture only takes 145 ms. The heat release, burning rate, and flame strength of the DAP-4/Ti mixture are better than those of other mixed energetic materials. The calculated apparent activation energy of DAP-4/Ti mixture is 150.4 kJ·mol −1 , which is 55 kJ·mol −1 lower than that of DAP-4. The apparent activation energies of Cl-20/Ti and HMX/Ti are 173.6 kJ·mol −1 and 317.2 kJ·mol −1 , respectively. These findings demonstrate that DAP-4/Ti mixed energetic materials exhibit good energy characteristics and combustion performance.
研究领域:
材料科学
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化学工程
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燃烧学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2024
·Vol. 35
·期 36
·1-12
·
IF 2.8
Wang Zheng,Ma Juncheng,Xiong Zhe,Yang Hongyu,Zhang Xing,Tang Bin
In this paper, the strategy of substituting Ti 4+ for Nb 5+ in Mg 4 Nb 2 O 9 microwave dielectric ceramic was employed to improve the microwave dielectric properties. Specifically, a maximum Q × f value of 137,462 GHz was obtained at x = 0.15, resulting in a nearly 30% increase in the quality factor ( Q × f ) for the Mg 4 Nb 2− x Ti x O 9− x /2 sample. Moreover, we investigated the phase composition, micromorphology, and the relationship between structural characterization and dielectric properties. The X-ray diffraction (XRD) patterns indicated that only a single Mg 4 Nb 2 O 9 phase with a trigonal corundum-type structure was formed in all the samples. The ɛ r was related to the ionic polarizability, and the τ f value was dependent on the B–O bond valence ( V B–O ) and BO 6 octahedral distortions. Ultimately, the Mg 4 Nb 1.85 Ti 0.15 O 8.925 ceramic sample exhibited microwave dielectric properties with ɛ r = 13.89, Q × f = 137,462 GHz, and τ f = − 55.1 ppm/°C.
研究领域:
材料科学
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电子材料
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陶瓷材料
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
·
IF 3.8
Xuliang Deng,Yang Xu,Jincheng Liu,Dong Lin,Ze Zong,Juncong Yuan,Zhiyang Li,Guanghui Zhao,Yongjun Zhang,Yibin Liu,Xiaobo Chen,Xiang Feng,De Chen,Chaohe Yang,Honghong Shan
Regulating the Ti active sites in titanosilicates with different coordination modes is of prime scientific and industrial significance to the rational design of efficient catalysts for olefin epoxidation. In this study, the Ti species in Ti-beta zeolite catalysts (open/closed tetra-coordinated Ti sites, hexa-coordinated Ti species, and TiO2) were keenly controlled via the dealumination-metallization approach. By multiple characterizations, kinetics study, and multivariate model analysis, it is found that the open tetra-coordinated framework Ti(OH)(OSi)3 species contribute more to the catalytic performance for 1-hexene epoxidation with H2O2. Moreover, the Ti-beta with rich open tetra-coordinated Ti(OH)(OSi)3 species showed significantly improved reaction performance (TON: 401, conversion: 64%, selectivity: 98%, H2O2 efficiency: 97%) with lower apparent activation energy. This study not only opens up new prospects for the design of efficient titanosilicates by modifying Ti microenvironments but also proposes the strategy to improve the content of open tetra-coordinated Ti sites.
研究领域:
催化
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材料科学
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化学工程
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无机化学
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DOI
高影响因子
Molecular Catalysis
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2017
·
IF 0
Yanping Zhu,Minwang Laipan,Runliang Zhu,Tianyuan Xu,Jing Liu,Jianxi Zhu,Yunfei Xi,Gangqiang Zhu,Hongping He
A novel and efficient photocatalyst was synthesized by surface hybridizing Zn/Ti-LDH (LDH) with C60 molecules. The structural characteristics of the resulting products (C60/LDH) were studied using a variety of characterization methods, and the photocatalytic activities of C60/LDH were tested using Orange II (OII) as a model contaminant under simulated solar irradiation. The FT-IR spectra showed that the characteristic mode of C60 at 1182 cm −1 split into two peaks at approximately 1240 and 1156 cm −1 ; in addition, the Raman spectra showed the band at 1422 cm −1 for C60 was upshifted to 1431 cm −1 with the increased doping amount of C60. In addition, the XPS spectra revealed that the peaks of O1s, Zn 2p, and Ti 2p were downshifted slightly. These results demonstrated that chemical interaction existed between C60 and LDH on C60/LDH. The UV–vis diffuse reflectance spectra confirmed that the absorbance of C60/LDH in visible-light region enhanced markedly, as compared with that of pristine LDH. The photoluminescence (PL) spectroscopic measurement revealed that the C60/LDH composites exhibited much weaker PL intensity than that of LDH sample, and the transient photocurrent ( I – V ) analysis showed that C60/LDH had higher photocurrent density than pristine LDH. The results of PL spectra and I–V analysis suggested that C60 molecule could effectively transfer the photoelectrons from the conduction band of LDH, leading to a lower recombination rate of the photo-induced electrons and holes. The photocatalytic experiments showed that C60/LDH had much higher photocatalytic activity in the decolorization of OII than that of pristine LDH, and 2%C60/LDH composite exhibited the highest photocatalytic activity. Furthermore, the stability test indicated that the decolorization efficiency of OII by 2%C60/LDH was still quite efficient after being used for 5 cycles.
研究领域:
材料科学
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环境科学
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DOI
APPLIED ORGANOMETALLIC CHEMISTRY
·
2015
·Vol. 29
·期 9
·618-623
·
IF 2.248
Hongxu Guo,Di Guo,Zishan Zheng,Wen Weng,Jianhua Chen
Ag nanoparticle (NP)-decorated MIL-125(Ti) microspheres (Ag@MIL-125(Ti)) were firstly fabricated via a facile hydrothermal and following photo-reduction method. The photocatalysts were characterized using X-ray diffraction, scanning and transmission electron microscopies, X-ray photoelectron spectroscopy and UV–visible diffuse reflectance spectroscopy. The characterization results indicated that Ag NPs were dispersed on the surface of MIL-125(Ti) microspheres, and the Ag NPs had a uniform diameter of about 40 nm. The composites exhibited excellent visible-light absorption, due to the modification with the Ag NPs. The photocatalytic activity for the visible-light-promoted degradation of Rhodamine B was improved through the optimization of the amount of Ag loaded as a co-catalyst, this amount being determined as 3 wt%. Additionally, studies performed using radical scavengers indicated that O 2 − and e − served as the main reactive species. The catalyst can be reused at least five times without significant loss of its catalytic activity. Furthermore, a photocatalytic mechanism for degradation of organics over Ag@MIL-125(Ti) is also proposed. Copyright © 2015 John Wiley & Sons, Ltd.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Jinsu Yu,Hsinshen Ho,Jiangyi Chen
As a transmission part, the service life of the shaft parts directly affects the machining efficiency and economic benefit, and requires higher surface hardness and wear resistance. In this study, the Ti/B 4 C/dr40 composite powder was cladded on the shaft part surface via laser cladding to improve the microhardness and wear resistance. The microstructure evolution and phase structure were analyzed to reveal the strengthening mechanism of Ti and B 4 C on dr40 coating. The Ti/B 4 C/dr40 composite coating with low defects and good interface metallurgical bonding quality between coating and substrate was prepared on the 45# steel shaft part. The results show that the main phase in the Ti/B 4 C/dr40 composite coating is TiC, TiB 2 , Cr 2 C 3 , (Ti, Cr) C, (Ti, Cr, Fe, Ni) (C, B). With the addition content of Ti increasing, the grain densifies, the sieve-reticular structure and small strip phase at grain boundary and intergranular area change as massive phase. Moreover, the microhardness improves up to 2.05 times than that of dr40 coating. The in-situ synthesis of carbides and borides are evenly distributed in the coating, which improves the deformation resistance of the coating. In addition, the precipitation and solid solution strengthening caused by reinforcement phase also enhanced matrix strength for supporting reinforcement phases, improving the coating wear resistance.
研究领域:
材料科学
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机械工程
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Xiuyuan Fan,Guohua Bai,Zhenhua Zhang,Xiaolian Liu,Jiaying Jin,Jiafeng Xu,Mi Yan
In this study, high-frequency MnZn ferrites are prepared for power applications at 10 MHz using solid-state reaction method. The sample doped with 3000 ppm TiO 2 yields the optimal comprehensive magnetic properties , with an initial permeability of 792, power loss of 415 kW/m 3 (10 MHz, 5 mT, 25 ℃), and saturation induction of 460 mT. This indicates significant progress compared to previously reported results. The mechanisms of property optimisation, microstructure and domain structure evolution also discussed with TiO 2 doping. The precipitation of Ti at the grain boundary can promote a high-density microstructure and favour the formation of magnetic monodomain in MnZn ferrites. Our results elucidate the correlations between microstructure, domain structure, and high-frequency performance, and present a potential roadmap for the development of high-frequency soft magnetic ferrites.
研究领域:
材料科学
·
磁学
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产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2024
·
IF 8
Zhaorui Zhang,Haiying Du,Huashuai Hu,Dongchen Tan,Jinkui Chu,Minghui Yang
Two-dimensional transition metal carbon nitrides (MXenes) are a prominent class of functional materials with significant potential for sensing applications. However, their conventional charge transfer mechanisms pose limitations for detecting nitrogen dioxide (NO 2 ). In this study, we successfully design-synthesized potassium titanate (KTO) nanoribbons by oxidizing and alkalizing monolayer Ti 3 C 2 T x MXene, targeting room-temperature NO 2 detection. The Ti 3 C 2 T x -derived KTO exhibited exceptional selectivity for NO 2 , achieving a remarkable response of 649.2 % for 50 ppm NO 2 , which is 550 times higher than that of the Ti 3 C 2 T x sensor (1.18 %). Additionally, the sensor demonstrated a detection limit as low as 5 ppb at room temperature, along with rapid response (1 s) and recovery times (2 s), and excellent linearity. Computational analysis showed that the abundant OH groups on the KTO surface contribute to strong selective adsorption (2.79 |eV|) and efficient electron transfer (0.91 |e|) for NO 2 . The unique proton conduction mechanism of KTO further reduced the activation energy for proton transport, enhancing NO 2 sensing performance. This study highlights the potential of Ti 3 C 2 T x -derived KTO nanomaterials for advanced room-temperature NO 2 detection and sensor technology development.
研究领域:
材料科学
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传感器技术
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环境监测
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）