CHEMICAL ENGINEERING SCIENCE
·
2019
·
IF 3.372
Piao Liu,Jianxin Cao,Zheng Xu,Chunliang Yang,Xiaodan Wang,Fei Liu
Core-shell structured ZSM-5@t-ZrO 2 catalysts were prepared by a hydrothermal coating method, and their physicochemical properties, catalytic performance, and deactivation behavior in thiolation reactions were studied using a ZSM-5/t-ZrO 2 physically-blended catalyst as a comparison. Reactions using the core-shell ZSM-5@t-ZrO 2 catalyst were carried out at a pressure of 0.7 MPa, 370 °C, a H 2 S:CH 3 OH molar ratio of 2:1, and a N 2 flow rate of 90 ml·min −1 . The conversion of CH 3 OH, and the selectivity and yield of CH 3 SH under these conditions were 92.07%, 90.89%, and 83.68%, respectively, and the catalytic lifetime was longer than 30 h. Compared with the ZSM-5/t-ZrO 2 physically-blended catalyst, the CH 3 SH yield and the catalytic lifetime of the core-shell structured ZSM-5@t-ZrO 2 catalyst were higher by 5.37% and 150%, respectively. The unique reaction pathway of the shell (t-ZrO 2 , Lewis (L) base active site)-core (ZSM-5, Brǿnsted (B) acid active site) and the Lewis-Brønsted acid active center based on a composite solid-solution interface were mainly responsible for the high activity of the thiolation reaction. Meanwhile, the formation of a micro-mesoporous system increased the diffusion of molecules and reduced the deactivation rate of carbon- and sulfur-containing deposits. Generally, carbon- and sulfur-containing substances deposited on catalysts were mainly composed of polymethylbenzene, polymethyl naphthalene, cyclic elemental sulfur, and other compounds containing C S and S S bonds. Finally, the core-shell structured catalysts showed excellent resistance to deactivation by carbon- and sulfur-containing deposits.
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
Journal of Inorganic and Organometallic Polymers and Materials
·
2012
·Vol. 23
·期 2
·393-400
·
IF 1.452
Jiang Hualin,Chen Pinghua,Luo Shenglian,Luo Xubiao,Tu Xinman,Cao Qun,Zhou Yanlei,Zhang Weibo
A novel biocompatible composite Fe 3 O 4 /ZrO 2 /chitosan was synthesized in a simple way and its capacity of dye removal was investigated in this study. The morphology of the material was examined by SEM and TEM and found to be nanosized and spheroidal. Equilibrium adsorption isotherms and dynamic behaviors of the adsorption process were investigated in detail. The material saturated with dye could be regenerated by treatment with strong alkali solution. The composite has high adsorption capacity towards acidic dyes represented by amaranth and tartrazine, and remains intact under conditions that are strongly acidic or alkali. The material has high potential to be applied for the removal of acidic dyes in industrial wastewater in large scale.
研究领域:
材料科学
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环境科学
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生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Wentao Hao,Yupeng Wang,Shuai Yang,Bo Yu,Jiangpeng Zhao,Haitao Huang,Panpan Xu,Li Sun,Ensi Cao,Yongjia Zhang
The dielectric-permittivity ( ε′ ) of (In 0.5 Nb 0.5 ) x Ti 1-x O 12 (INTO) ceramics exceeds 10 4 at room temperature, but the large low-frequency dielectric loss ( tanδ ) limits their applications. Origin of the giant ε′ phenomenon in kHz frequency range is still controversial. However, based on the experimental results, an internal barrier layer capacitance (IBLC) effect seems to be the most plausible mechanism. According to IBLC effect, constructing insulating phase boundaries in INTO ceramics is an effective way to reduce their low-frequency tanδ . Therefore, INTO-based ceramics with ZrO 2 phase boundaries were prepared by solid-state reaction, and their crystalline structures, microstructures, dielectrical properties and complex impedances were analyzed systematically. The results show that the tanδ of our INTO-based ceramics decreased from 0.11 to 0.024 at 1 kHz by ZrO 2 adding and annealing in atmosphere, because of the resistance of ZrO 2 phase boundaries increasing.
研究领域:
材料科学
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电子材料
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产品关联
DOI
高影响因子
Results in Physics
·
2019
·
IF 3.042
Baosong Li,Dandan Li,Tianyong Mei,Weiwei Zhang
Ni-W/ZrO 2 -CeO 2 composite coating has been fabricated via pulse electrodeposition. The structure, morphology, composition and the operating parameters of the nanocomposite coating were evaluated and optimized for the enhanced hardness and corrosion resistance. It illustrated that the deposited coatings are dense, crack-free with nodular or granular structure. The average current density of 4–6 A dm −2 , duty cycle of 70% is beneficial to the finer structure and higher content of nanoparticles in deposits. The average roughness, crystallite size and growth rate of the composite coating was examined. The hardness as a function of duty cycle, current density and deposition time were investigated. The optimal parameters for the improved performance of the composites were given. It was illustrated that the reinforcing particle phase had been uniformly co-deposited in the coating. The embedded ZrO 2 and CeO 2 particles could enhance the corrosion resistance and hardness of Ni-W metallic matrix. Ni-W/ZrO 2 -CeO 2 nanocomposite coatings possess higher performance in aggressive environment and exhibit great application values.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2016
·
IF 3.847
Hui-Gang Wang,Guo-Liang Shi,Feng Yu,Rui-Feng Li
A solid super acid catalyst, S 2 O 8 2 − /ZrO 2 , was prepared by a new synthesis route of one-pot method with ammonium persulfate via vapor phase hydrolysis to improve biodiesel production using expired soybean oil as reactant. Catalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), and NH 3 -temperature programmed desorption (NH 3 -TPD) to determine the optimum pretreatment conditions and understand the role of the active sites for transesterification . S 2 O 8 2 − /ZrO 2 calcined at 500 °C, which showed an amorphous phase by XRD characterization, was identified as composed of tetragonal phase ZrO 2 microcrystallites by TEM examination. The microcrystallites which anchored more S 2 O 8 2 − had abundant super acid and displayed high catalytic activity in the transesterification under mild reaction conditions. The reaction parameters over the catalyst were optimized and both the conversion of soybean oil and selectivity of biofuel reached 100% under the conditions of 110 °C of reaction temperature, 4 h of reaction time and 20:1 of methanol to oil molar ratio . Moreover, the catalyst showed high stability in the reactions and no sulfur leaching was found in the biodiesel products in cyclic utilization.
研究领域:
化学工程
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催化
·
生物燃料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Yiming Chen,Chuan Wang,Yi Liu,Qianwen Zhang,Ling Zhou,Yi Zhang
The selectivity and stability of catalysts for methanol synthesis from CO 2 still remain to be enhanced. In this work, we synthesized a series of Pd/ZrO 2 catalysts inversely loaded with various metal oxide promoters (ZnO, In 2 O 3 , and CeO 2 ), those would partially cover Pd metal surface and form some new metal-promoter interface, to explore the nature in the performance of CO 2 hydrogenation to methanol. The catalyst synthesized by this approach could limit the growth of Pd particles during the reduction and form new metal–metal oxide interfaces with different functions of CO 2 hydrogenation, improving the reaction performance of Pd-ZrO 2 catalysts. As a result, the ZnO-Pd/ZrO 2 catalyst exhibited the highest CO 2 conversion (12.0 %), methanol selectivity (95.6 %), and STY of methanol (472 g MeOH kg cat -1 h −1 ), with excellent stability. The results of HRTEM, H 2 -TPR, XPS, and XAFS showed that the ZnO-Pd/ZrO 2 catalyst had the typical Pd-ZnO interface with Pd 2+ species after the H 2 reduction, which could enhance the adsorption and activation of CO 2 . In addition, the in situ DRIFTS and NAP-XPS results implied that the Pd-ZnO interface significantly improved the formation of formate (HCOO*) and methoxy (H 3 CO*) species, which were considered to be the key intermediates of methanol generation, and thus greatly enhanced the selectivity of methanol.
研究领域:
催化
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化学工程
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材料科学
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环境化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 126
·103982-103988
·
IF 3.84
Zheng Han,Xiang Li,Minhua Zhang,Zongzhang Liu,Meixiang Gao
A series of ZrO2–SiO2 catalysts synthesized by sol–gel method were investigated for the 1,3-butadiene formation from bioethanol and acetaldehyde. The influence of ZrO2 content and reaction conditions on catalytic performance were studied. The catalysts were characterized by N2 adsorption–desorption analysis, temperature-programmed desorption of NH3 (NH3-TPD), IR spectroscopy of adsorbed pyridine (Py-IR), Fourier Transform Infrared Resonance (FTIR), X-ray diffraction (XRD) and Transmission Electron Microscope (TEM). These characterization results indicated that suitable intensity of acid sites, especially Lewis acid, are very crucial to obtain an active catalyst. The catalysts showed significantly higher selectivity for C4 chemicals, and 2 wt% ZrO2 content reached the highest selectivity to BD (69.7%), at space velocity (WHSV) of 1.8 h−1.
研究领域:
催化化学
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可再生资源转化
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材料科学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
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2023
·
IF 6.7
Jinghua Li,Jia Lin,Xiaohua Chen,Meiqiu Feng,Ying Zheng
Palladium-based catalysts are relatively active for eliminating anthropogenic methane emissions through catalytic combustion, while they tend to degrade under drastic conditions. Herein, the silicon promoter was rationally introduced into Pd/ZrO 2 catalysts to tune the monoclinic ( m -) and tetragonal ( t -) phase ratio and boost the catalytic performance. The introduced Si–O–Zr structure in ZrO 2 not only reduced the grain size, but also produced oxygen vacancies due to lattice distortion, which greatly improved the stability of t -ZrO 2 in high-temperature (800 °C) calcined catalysts. However, the excessive Si-addition caused the blockage of oxygen vacancies by amorphous SiO 2 , facilitating the transformation from t -ZrO 2 to m -ZrO 2 . In the Pd/0.05Si–ZrO 2 catalyst with a relatively high t -ZrO 2 ratio, the presence of abundant oxygen vacancies stimulated the formation of surface-active oxygen and Pd 2+ species, improved the reducibility of PdO and the redox of Pd ↔ PdO, meanwhile depressed the accumulation of hydroxyls. These, coupled with the enhanced hydrophobicity by Si-modification, made Pd/0.05Si–ZrO 2 exhibit superior catalytic activity, stability and water-resistance to catalysts with low t -ZrO 2 ratio. The revealed Si-promotion effect could be generalized to design phase-regulated Pd-based catalysts with optimized surface property for catalytic oxidation reactions.
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
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2024
·
IF 6.5
Xiao Han,Ziqi You,Yufeng Liu,Ruina Ma,Yongzhe Fan,An Du,Xue Zhao,Mingxu Yang
In this study, superhydrophobic coatings characterized by micro- and nanostructures were fabricated using a simple spraying method. The water contact angle of the ETFE-ZrO 2 composite coating achieved a maximum of 157.3° after three spraying applications, with a mass ratio of ethylene-tetrafluoroethylene copolymer (ETFE) to modified ZrO 2 particles established at 1:1. This coating had good corrosion resistance, as demonstrated by a reduction in corrosion current density to 2.162 × 10 −6 A/cm 2 , which is an order of magnitude lower than that of Q345 steel. Following immersion in a 3.5 wt% NaCl solution for 72 h, the superhydrophobic coatings retained their hydrophobic properties. Furthermore, these coatings demonstrated good chemical stability, maintaining a water contact angle >150° across a pH range of 3 to 12. Additionally, the coatings exhibited effective self-cleaning properties and photocatalytic effects. The rapid fabrication of these coatings presents significant advantages for the development of large-area, superhydrophobic, and self-cleaning surfaces, as they do not require complex modifications or reactions.
研究领域:
材料科学
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表面工程
·
腐蚀防护
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Wei Gao,Yongzheng Zhang,Yanli Wang,Liang Zhan
The carbon/phenolic composites are extensively considered as an efficient ablative thermal protection material, but inferior oxidation-ablation resistance has limited their further application. In this work, a multiscale ZrO 2 -SiOC coated carbon/phenolic composite (NCF/ZSAx-PA) was fabricated through a dual-stage construction strategy. The as-prepared composites exhibited a low density (0.314–0.348 g/cm 3 ), low thermal conductivity (0.0605–0.0725 W/(m·k)) and promoted compressive strength (2.95/5.08 MPa in the Z/XY direction). Benefiting from the formation of a protective ZrO 2 -SiO 2 ceramic coating, the multiscale composites showed excellent anti-oxidation and ablation performance. The residual weight of NCF/ZSAx-PA was 19.41 % at 1000 °C while the unmodified carbon/phenolic composites were entirely burnt off under an air atmosphere. Besides, the NCF/ZSAx-PA exhibited low back temperature (53.6 °C), low linear ablation rate (0.0519 mm/s), and low mass loss rate (0.0100 g/s) under the 3.62 MW/m 2 oxyacetylene assessment. All the superior properties enabled the NCF/ZSAx-PA a prospective application on the thermal protection system.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2025
·Vol. 18
·期 10
·2289
·
IF 3.2
Junyao Shen,Tian Si,Huan Gao,Linhua Zhu,Heng Zhang,Xin Gao,Xiaoning Tang
ZrO 2 and multi-walled carbon nanotubes (MWCNTs) were selected as single-phase and composite toughening agents to investigate the influence on the mechanical properties of CaZr 4 (PO 4 ) 6 (CZP) ceramics. The results revealed that the addition of single-phase or composite toughening agents had minimal impact on the phase composition and crystallinity of CZP ceramics. When the content of the single-phase ZrO 2 toughening agent reached 10 wt.%, the flexural strength of CZP ceramics increased to 71.60 MPa due to the particle toughening mechanism of ZrO 2 . With the addition of 1.0 wt.% ZrO 2 and 0.3 wt.% MWCNTs, the CZP ceramics demonstrated enhanced densification and improved sintering activity. The small-sized ZrO 2 particles were evenly dispersed within the ceramic matrix, accompanied by a phase transformation during sintering. Together with MWCNTs, this combination resulted in a significant increase in flexural strength, reaching 138.43 MPa. An in-depth analysis of the toughening mechanisms indicated that the CZP ceramic matrix primarily featured ZrO 2 phase transformation toughening and the pull-out and bridging toughening provided by MWCNTs. The synergistic interaction of these multiple toughening mechanisms significantly enhanced the mechanical properties of CZP ceramics, providing valuable theoretical insights for optimizing the performance of phosphate ceramics in practical applications.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Wenhui Li,Jiaxing Zhang,Xiao Jiang,Minchen Mu,Anfeng Zhang,Chunshan Song,Xinwen Guo
Carbon dioxide (CO2) hydrogenation to gasoline through the methanol-mediate route using the metal oxide/ZSM-5 tandem catalyst has attracted considerable attention to reduce the pernicious effect of CO2 on global climate change and to reduce our dependence on fossil fuels. The C5+ molecules are preferred to pass through the straight channels of ZSM-5 zeolite, where side reactions may occur on the acid sites and the catalyst is deactivated due to pore blockage. Thus, the thickness of ZSM-5 along the straight channel, namely the b-axis direction, is crucial to manipulating the product distribution and catalyst lifetime. Here, HZSM-5 nanosheets with different thicknesses (2 nm to 2 μm) along the b-axis were synthesized controllably and composited with In2O3/ZrO2 as tandem catalysts for CO2 hydrogenation to gasoline. In2O3–ZrO2/HZSM-5 with a thickness of 20 nm shows the highest selectivity toward C5+ hydrocarbons under isoconversional conditions and no deactivation after 150 h of reaction with less carbon deposition compared with the 2 μm one. Comparative activity tests and characterization results demonstrate that an appropriate length of straight channels can benefit the production of C5+ hydrocarbons through the polymerization of short-chain molecules while preventing the cracking of long-chain hydrocarbons on acid sites. Adding an appropriate loading of Co into tandem catalysts with optimal composition gives rise to further enhancement in CO2 conversion by 10%, and a slight increase in C5+ selectivity. This can be attributed to the Co-induced hydrogen spillover from metallic Co to support ZrO2, facilitating the formation of the key intermediate and its subsequent hydrogenation steps. This study provides insights into designing effective and anti-carbon deposition tandem catalysts for CO2-to-gasoline by manipulating the channel length–resident time–acidity relationship and the promoter effect.
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
危险品化学品经营许可证（带存储）