JOURNAL OF CATALYSIS
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2025
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IF 6.5
Tianyu Gao,Weixiao Sun,Haiyong Wang,Jing Zhang,Zhen Yan,Martine Trentesaux,Maya Marinova,Chenguang Wang,Vitaly Ordomsky,Sébastien Paul
Styrene oxide is an important intermediate in many chemical syntheses. It can be produced through the epoxidation of styrene using supported metal catalysts. However, the catalytic performance and stability of these catalysts are negatively affected by the mass transfer, diffusional limitations and leaching of metals from supports. In this work, a hydroxyl-substituted bidentate 2D Schiff-base COF supported Fe 3 O 4 particles catalyst (Fe-COF) is developed for styrene epoxidation using H 2 O 2 as oxidant. Fe-COF catalyst possesses an eclipsed layered-sheet structure with a uniform distribution of Fe 3 O 4 particles. Supported Fe 3 O 4 particles as the active sites are responsible for the adsorption of styrene and generation of reactive oxygen radicals through the Fenton process. The presence of the extensive π-electron delocalization effect over COF support facilitates the electron transfer between Fe 2+ and Fe 3+ sites on Fe-COF catalyst during the reaction, accelerating the Fenton process, thus Fe-COF catalyst even shows a higher catalytic activity (86.0 % conversion of styrene and 88.0 % selectivity to styrene oxide) compared with homogeneous Fenton catalyst (Fe(NO 3 ) 3 ). In addition, Fe-COF catalyst demonstrates good stability after 5 recycles without Fe leaching, due to the coordination of Fe 3 O 4 particles with the imine and hydroxyl groups in COF support.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
ChemPhotoChem
·
2022
·Vol. 6
·期 9
·e202200075
·
IF 3.679
Qingping Ke,Shuai Fang,Jun Tang,Fengfeng Li,Chuantao Ning,Zhicheng Tang,Qiang Ling,Xiangchun Liu,Ping Cui
Graphical Perovskite LaSrCoFeO 6 (LSCF) oxide was investigated as a heterogeneous visible-light catalyst. The material was found to demonstrate highly efficient catalytic performance for the epoxidation of styrene under aerobic conditions. In the search for a highly efficient heterogeneous catalyst for the epoxidation of styrene, it is still a challenge to develop a system that simultaneously possesses superior catalytic activity and selectivity under aerobic conditions. Herein, we report the use of perovskite LaSrCoFeO 6 (LSCF) as a heterogeneous and visible-light catalyst, and determine that LSCF acts as a highly efficient catalyst for the epoxidation of styrene under aerobic conditions. The formation of 1 O 2 species transformed from O 2 ⋅ − species were proposed as reactive oxygen species for the epoxidation of styrene over the LSCF catalyst, where the directional generation of O 2 ⋅ − species on the LSCF catalyst is the key step to yield highly selective epoxidation of styrene. The experimental results of styrene epoxidation show that when the molar ratio of styrene and LSCF catalyst is 150 : 1 and the reaction is under the conditions of visible light (440 nm) and 100 °C for 6 h, the conversion of styrene and selectivity of styrene oxide reached 99.9 % and 80.3 %, respectively. The reaction rate over LSCF catalyst is as high as 50 mmol ⋅ g cat −1 ⋅ h −1 . In addition, the reaction kinetics of the epoxidation of styrene over LSCF catalyst was systematically studied.
研究领域:
材料科学
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催化化学
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环境科学
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DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Zhibo Xu,Fumin Wang,Xubin Zhang,Yi Zhai,Linfang Jiang,Kaiwei Wang,Yongwang Li,Qing Zhang
To enhance the doping of vanadium in zeolites and achieve high stability, the selection of vanadium precursors containing specific vanadium species can effectively overcome this crucial problem. Two series of V x Si-Beta(A) and V x Si-Beta(N) zeolites have been prepared by a two-step post-synthesis method at pH = 1 and pH = 7. The properties and environments of vanadium in samples are investigated by UV–vis, XPS, EPR, H 2 -TPR and 51 V MAS NMR. The bonding between vanadium and framework in VSi-Beta(A) is stronger than that of VSi-Beta(N). After the two are calcined or hydrated, the vanadium species in the former are relatively stable, while the pseudo-tetrahedral V(V) species and pseudo-octahedral V(V) species in the latter are interconverted. The changes of vanadium species in the supernatant during the preparation have been investigated by 51 V static NMR. At low concentration and pH = 1, there is a unique mononuclear cation (VO 2 + ) in the aqueous NH 4 VO 3 solution, which is favorable for the interaction with the negatively charged hydroxyl nests generated after the nitric acid dealumination , and enables the V atoms to be tightly inserted into the framework. In styrene epoxidation, the type of V(V) species in the catalyst could significantly affect its catalytic performance, and the catalytic activity and stability of V x Si-Beta(A) are superior than that of V x Si-Beta(N).
研究领域:
材料科学
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催化化学
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DOI
高影响因子
JOURNAL OF POROUS MATERIALS
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2022
·Vol. 30
·期 3
·921-936
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IF 2.523
Guangjian Wang,Hongyu Gao,Qingxi Cao
Mesoporous molecular sieves silica materials had been functionalized employing 3-aminopropyltriethoxysilane as the surface decoration agent by a post-synthesis method and Eu and Ti with different loading ratio were synchronously anchored on amino-functionalized silica framework by incipient wetness impregnation method, respectively. The structures of the synthesized samples were evaluated by means of X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible spectra, scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy and solid-state 29 Si magic angle spinning nuclear magnetic resonance spectra. The results revealed that the highly ordered mesoporous two dimensional hexagonal structure and the mesoporous channel structure were well preserved and isolated tetrahedral surface Eu3+ and isolated [TiO4] or [HOTiO3] species were found to be grafted and highly dispersed in the amino-functionalized mesoporous framework. A significant enhancement in selectivity and conversion for the photocatalytic epoxidation of styrene has been achieved by synergistic effect based on surface ligand effect and electron density effect between Eu 3+ and Ti 4+ species on amino-functionalized mesoporous silica framework. The factors associated with the conversion of styrene and selectivity to styrene oxide such as the solvent, metal loading, the amount of NaOH, H 2 O 2 /Styrene, the amount of catalyst and reaction time were also investigated in details. The desired selectivity (84%) to styrene oxide and excellent conversion (32%) of styrene for the photocatalytic epoxidation of styrene with turnover frequency of 3.1 × 10 −4 s −1 were obtained using aqueous H2O2 as an oxidant in the presence of acetonitrile solvent under ambient temperature.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Kaiwei Wang,Fumin Wang,Yi Zhai,Xubin Zhang,Mingshuai Sun,Jinjin Zhang,Xiaolu Fan,Changhao Bing
The metal species embedded in specific positions within the zeolite framework and their unique microenvironment exhibit fascinating effects on catalytic performance. Herein, we incorporated tetrahedrally coordinated Co 2+ into the framework of hollow silicate-1 zeolite and investigated the influence of halogen anions (Cl - , Br - and F - ) in the synthesized gel on the distribution of cobalt species in the channels. The addition of an appropriate amount of inorganic ammonium salts and seeds was found to be a necessary condition for cobalt incorporated into the framework. Notably, the Cl - anions present in the synthesis gel can induce more cobalt species located at the intersection cavity of silicate-1 (β-type). Comprehensive characterization results indicate that the tetrahedrally coordinated Co 2+ in the intersecting cavities of hollow zeolite appears to exhibit more efficient styrene epoxidation performance. This work presents a simple and cost-effective method to synthesize hollow cobalt-based zeolite with adjustable metal distribution in channels. By regulating the spatial distribution of cobalt species with halogens, the CS-0.1–0.5-Cl catalyst enhanced activity and selectivity in the epoxidation reaction of styrene to styrene oxide. Specifically, at a temperature of 80 °C after a reaction time of 6 h, the catalyst demonstrated a styrene oxide yield of 42.47 % and a excellent styrene oxide selectivity of 82.29 %.
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
The Innovation
·
2021
·
IF 0
Hao Tan,Peng Kong,Riguang Zhang,Mengting Gao,Meixian Liu,Xianmo Gu,Weifeng Liu,Zhanfeng Zheng
The controlled generation of reactive oxygen species (ROS) to selectively epoxidize styrene is a grand challenge. Herein, cyano-group-modified carbon nitrides (CNCY x and CN-T y ) are prepared, and the catalysts show better performance in regulating ROS and producing styrene oxide than the cyano-free sample. The in situ diffuse reflectance infrared and density functional theory calculation results reveal that the cyano group acts as the adsorption and activation site of oxygen. X-ray photoelectron spectroscopy and NMR spectrum results confirm that the cyano group bonds with the intact heptazine ring. This unique structure could inhibit H 2 O 2 and ⋅ OH formation, resulting in high selectivity of styrene oxide. Furthermore, high catalytic activity is still achieved when the system scales up to 2.7 L with 100 g styrene under solar light irradiation. The strategy of cyano group modification gives a new insight into regulating spatial configuration for tuning the utilization of oxygen-active species and shows potential applications in industry.
研究领域:
化学工程
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材料科学
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催化反应
✓ 已验证
DOI
Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 16
·10374-10384
·
IF 12.732
Yang Gao,Chen Xing,Shuqi Hu,Shiguo Zhang
A Au-doped SrTiO3 perovskite oxide catalyst (Sr0.995Au0.005TiO3−δ) has been designed and synthesized based on thermodynamic analysis and density functional theory calculations. During reduction, Au nanoparticles with an average diameter of 2 nm are in situ exsolved and evenly distributed on the surface of a SrTiO3 substrate. The as-prepared catalyst shows a high conversion of 95.0% and a high selectivity of 96.3% towards styrene epoxidation in CH3CN using H2O2 as the oxidant, and the conversion maintained at 78.2% after five cycles. Noteworthily, such performances surpass those of ex situ deposited Au nanoparticles on SrTiO3 with the same loading (88.5% initial conversion and 90.1% initial selectivity; 48.1% conversion after five cycles). The enhancement is attributed to the smaller particle size and stronger particle–substrate interaction, as revealed by XPS and TEM characterization. Mechanistic investigation confirms the strong support effect in the in situ exsolution system, where charge is transferred from SrTiO3 to Au, improving the reactivity and selectivity. The results demonstrate the unique advantages of the in situ exsolution approach, which may further be applied to develop heterogeneous catalysts with stable nanoparticles.
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
MICROPOROUS AND MESOPOROUS MATERIALS
·
2016
·
IF 3.349
Fu Yang,Shijian Zhou,Shuying Gao,Xianfeng Liu,Saifu Long,Yan Kong
In this paper, a new templating assemble route (S 0 M + I − ) was proposed to construct a nickel-based mesoporous silica catalyst. During this method, the neutral surfactant dodecyl amine was used as a special agent for both capturing the metal ions and structure-directing of the mesoporous silica. Based on the templating assemble route, metal cations were highly enriched in the interface of micelles and silicate wall by the physiochemical interaction among the surfactant (S 0 ), metal cations (M + , Ni 2+ ) and silicate oligomers (I − ). Besides, instead of original hydrogen-bonding, the addition of metal cations in the assemble process made the interaction between micelles and silicate oligomers improved significantly through the counterion-mediated interaction. According to these effects, highly-dispersed, ultra-fine and accessible nickel oxide nanoparticles (NPs) were in situ produced and embedded in the channels and the exposed level of the active sites on these NPs would reach to the highest. Moreover, as expected, the synthesized catalyst exhibited superior catalytic activities for the epoxidation of styrene .
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
ACS Sustainable Chemistry & Engineering
·
2016
·
IF 5.267
Xiangcun Li,Wenji Zheng,Bo Chen,Le Wang,Gaohong He
In this work, for the first time, AuPt alloy yolk@shell hollow nanoparticles (NPs) were constructed and simultaneously embedded into hollow interiors of a mesoporous silica microsphere based on a rapid aerosol process (AuPt@SiO2). Resin nanospheres were utilized both as a hard template to create hollow interiors inside the mesoporous silica microspheres and as carriers to transport pregrown metal nanocrystals, AuPt alloy clusters, into the microspheres. Calcination removes the resin nanospheres and causes metal nanocrystals to embed into the hollow interiors of the silica microspheres. Due to the unique yolk@shell hollow structure of the AuPt nanoalloy, ordered mesopores (67 nm) in the silica support, the synergetic effect between the AuPt alloy and the high surface area and pore volume of the microspheres, the AuPt@SiO2 spheres showed an excellent catalytic performance for styrene epoxidation with the conversion and selectivity of 85% and 87%, respectively. Notably, the novel catalyst showed a stable catalytic performance after five cycles of usage, suggesting the possible practical applications of the AuPt nanoalloy catalyst. In addition, the catalyst also exhibited a higher activity than the commercial Pt/C catalyst for the reduction reaction of 4-nitrophenol. The approach reported in this study could potentially be used to simplify the fabrication process of yolk@shell or hollow metal nanospheres, facilitating encapsulation of monometallic and multimetallic metal nanocrystals with various nanostructures and compositions into porous supports and thus guiding the design of catalysts with a special structure and high-performance.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
Journal of Flow Chemistry
·
2020
·Vol. 10
·期 1
·227-234
·
IF 3.622
Yuan Wei-Qiang,Zhou Shou-Quan,Jiang Yu-Yan,Li Hao-Hong,Zheng Hui-Dong
Considering the low conversion and long reaction time in scaling up reaction in batch reactor, the organocatalyzed epoxidation reaction of styrene was intensified under continuous flow conditions using a commercial fluidic reactor (Corning Advanced Flow G1 Reactor). After investigating the effect of reaction temperature, catalyst amount, MeCN/ t -BuOH ratio, F O / F AB (buffer solution amount), total feed flow rate and operating mode on the epoxidation reaction, the optimal reaction conditions were identified under continuous flow conditions. Upon optimization, high conversion and excellent selectivity with short reaction time (3.17 min) can be obtained. We successfully developed a process for the rapid and continuous epoxidation of styrene using an organocatalyst with hydrogen peroxide as the oxidant. Compared with the batch conditions, the continuous flow reactor can exhibit unique advantages including high-speed, safety, continuousness and absence of amplifying effect, which will be significant for the industrial production of epoxides.
研究领域:
化学工程
·
有机合成
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Yuxin Wu,Zhuo Chen,Yundong Wang,Jianhong Xu
The olefin epoxidation reaction is of great interest in recent years since epoxide is considered an important intermediate for a wide application range. H2O2-based catalytic epoxidation possesses the advantages of being cheap, green, and safe, which are quite advantageous in chemical technology. A phase-transfer catalyst, especially the phosphotungstate catalyst, has been applied in the epoxidation reaction with a high reaction rate and moderate reaction conditions. In this work, a phase-transfer catalyst, [(C18H37)2(CH3)2N]7[PW11O39], has been synthesized, and it showed high catalytic efficiency in styrene epoxidation. The influence of reaction time, temperature, oxidant concentration and amount, catalyst amount, and substrate concentration on the reaction performance was studied. A styrene conversion of 90.1% and selectivity of 90.6% could be achieved at 85 °C for 1 h with 3 equiv of H2O2 and 1.5 mol % catalyst. More importantly, kinetic models for the reaction network have been studied to optimize the reaction conditions and limit the side reactions.
研究领域:
化学工程
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催化化学
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产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2022
·
IF 6.562
Zhanyu Zhang,Jun Tang,Junbao Chen,Peixin Cui,Siyu Jiao,Wei Yi,Qingping Ke,Hengquan Yang
The epoxidation of styrene is an important route to synthesize organic intermediate, but how to effectively promote the formation of target superoxide radicals and then regulate the production of styrene oxide in two-phase reaction system remains an urgent challenge. In this study, MnO x nanocatalysts with abundant oxygen vacancies were fabricated using reverse-micelle as template, and then were endowed with an amphiphilic surface through post-modification. With such MnO x catalysts, Pickering emulsion could be formulated, in which numerous compartmentalized droplet microreactors were created for the epoxidation of styrene. The rich oxygen defects on MnO x were found to be useful to improve the chemisorption of t -butylhydroperoxide, and the active complexes formed by coordination of Mn 3+ with N, N-dimethylformamide favored the generation of preferable superoxide radicals for the synthesis of styrene oxide. Moreover, it was also found that compartmentalization effects arising from Pickering emulsion droplets modifies the radicals reaction path, significantly improving the catalytic efficiency and selectivity. As a result, in the Pickering emulsion system, 90.0% selectivity towards styrene oxide and a turnover frequency of 581 h −1 could be obtained, which were higher than ever reported results. The Pickering emulsion-based compartmentalized microreactors can provide versatile platforms to efficiently control the epoxidation of styrene involving free radicals.
研究领域:
化学工程
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催化科学
✓ 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）