CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Leilei Hou,Siyang Yan,Liping Liu,Jiaxu Liu,Guang Xiong
The TS-1 microsphere was facilely prepared via a direct spray drying of the mixture containing the nanocrystal TS-1 and mother liquor. The calcined TS-1 zeolites possess a hollow structure and numerous intercrystalline mesopores, which may facilitate the diffusion properties. Au nanoparticles were loaded on TS-1 support by utilizing a deposition–precipitation process to prepare the Au/TS-1-M catalysts for propylene epoxidation in the presence of H 2 and O 2 conditions. The effects of the Ti and Au loadings on the structure, porosity, morphology, and catalytic performances of the Au/TS-1 catalysts have been investigated by various techniques. Under the optimized synthesis conditions (Si/Ti molar ratio = 57, 0.49 wt% Au), a propylene conversion of 6.1 % and a PO selectivity of 91.7 % were obtained on the Au/TS-1 catalyst. A PO formation rate of 186.8 g PO ·kg cat. −1 ·h −1 was achieved at the 20th hour.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Xiu Gao,Yingqi Zhang,Yanping Hong,Beining Luo,Xianzai Yan,Guoqiang Wu
Methyl oleate (MO) macromolecules are unable to access the microporous channel of conventional titanium silicalite-1 (TS-1) zeolite , which leads to the low catalytic activity of epoxidation of MO. Herein, the small-size TS-1 (TS-1-s) zeolite with a large surface area was synthesized successfully through steam-assisted crystallization, and then a novel blocked TS-1-s supported molybdenum (Mo/TS-1-bs) catalysts were prepared for efficient epoxidation of MO with clean H 2 O 2 to produce epoxidized methyl oleate (EMO). Various characterization results show the introduced Mo species are highly dispersed on the outer surface of TS-1-s without destroying the structure of the MFI type zeolite and the tetrahedral framework titanium (Ti 4+ ). Interestingly, a large number of Mo 6+ species exhibit certain epoxidation activity attributing to the generating of electrophilic molybdenum hydroperoxide (Mo–OOH) species via Mo species combined with H 2 O 2 , which could adsorb and react easily with MO molecules. Furthermore, the Mo species are also coordinated with Ti 4+ species through the O atom resulting in the facile attack of the Ti–O bonds by H 2 O 2 and easy to form an active intermediate. Therefore, compared with the conventional TS-1, the Mo/TS-1-bs shows higher catalytic activity in the epoxidation reaction. However, the acidity of Mo/TS-1-bs catalysts increases with increasing the Mo-loading owing to the formation of Lewis acid, which leads to the side reactions and the decrease of EMO selectivity. As a consequence, the efficient, non-corrosive and green catalytic system for epoxidation of MO was developed, and the activity improvement of Mo species and the influence of acid were also demonstrated.
研究领域:
催化化学
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材料科学
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绿色化学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
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IF 4.8
Yuqing Ouyang,Ningning Du,Xiaoyun Xiong,Qingxun Hu,Hongman Sun,Tingting Li,Jie Zhong,Youhe Wang,Zifeng Yan
The combination of titanium silicalite-1 (TS-1) zeolite and H 2 O 2 oxidant provides an excellent alternative to many highly toxic and polluting olefin oxidation processes due to the by-product being water-only and without deep oxidation. However, the diffusion of bulky reactants and products suffers from the inherent micropores of conventional TS-1 zeolites. Herein, we designed a reticulated ordered macroporous carbon material with uniform and coherent mesopores, and successfully synthesized ordered hierarchical TS-1 zeolites containing intracrystalline macroporous-mesoporous-microporous by dry gel method. The fully interconnected intracrystalline macroporous-mesoporous-microporous hierarchical TS-1 improves the accessibility of the active site and the diffusion efficiency of bulky compounds. It showed excellent catalytic performance during the epoxidation reaction of chloropropene, and its epichlorohydrin yield and H 2 O 2 effective utilization were 70.11% and 77.05%, which were 2.2 and 1.9 times of the catalytic performance of commercial TS-1 zeolites, respectively, and significantly better than the ultrafine TS-1 synthesized by conventional methods. The high catalytic performance was maintained after three cycles of use. This offers a good opportunity for the design and synthesis of efficient zeolite catalysts in the future.
研究领域:
材料科学
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化学工程
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催化
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
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2018
·Vol. 6
·期 20
·9473-9479
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IF 9.931
Tianjun Zhang,Xiaoxin Chen,Guangrui Chen,Mengyang Chen,Risheng Bai,Mingjun Jia,Jihong Yu
Nano-sized hierarchical titanosilicate TS-1 without extra-framework anatase TiO2 has been successfully synthesized by using Triton X-100 as a mesoporous template under rotational crystallization conditions. The resultant material contains a large external surface area and uniform mesopores (2–4 nm). Notably, the titanium ions are fully incorporated into the framework of TS-1 and no extra anatase TiO2 exists. Triton X-100 and rotational crystallization conditions play an important role in eliminating anatase TiO2. The addition of Triton X-100 slows down the crystallization rate of TS-1, while the rota-crystallization accelerates the incorporation rate of Ti, so that the insertion rate of titanium into the framework matches well with that of silicon. As such, the generation of extra-framework anatase TiO2 can be inhibited. Furthermore, in comparison with nano-sized hierarchical TS-1 prepared under static conditions, nano-sized hierarchical TS-1 prepared under rotational conditions exhibits excellent catalytic activity and high stability in alkene epoxidation, especially in bulky alkene epoxidation. The facile synthetic strategy for nano-sized hierarchical TS-1 without extra-framework anatase TiO2 may open new perspectives for its potential application in selective oxidation reactions involving large molecules.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2025
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IF 3.4
Hongyu Wang,Fumin Wang,Kaiwei Wang,Xubin Zhang,Changhao Bing,Xiaolu Fan,Tongxue Zhang,Syed Mujtaba ul Hassan
Developing an approach for the efficient synthesis of TS-1 zeolites with desirable morphologies and tunable coordination environments for Ti active sites is a pivotal challenge in the design of high-performance catalysts and zeolite crystal engineering. Herein, we report a cost-effective and efficient additive, guanidinoacetic acid (GAA), and conduct a systematic study on the synthesis of plate-like TS-1 zeolites using GAA as an additive. Introducing GAA during hydrothermal synthesis not only modulates the morphology of TS-1 crystals but also permits GAA to adequately chemically interact with titanium precursors to form hexa-coordinated Ti species. TS-1 zeolites with a controllable b-axis thickness in the range of 80–110 nm, and abundant framework Ti and hexa-coordinated Ti species are successfully achieved by optimizing the synthetic parameters. Through SEM, FT-IR, XPS, TEM, and XRD analysis, the mechanism of GAA altering crystal growth is mainly to inhibit the growth of the (010) plane. A b-axis-oriented TS-1 zeolite enriched with hexa-coordinated Ti species displays better catalytic performance in the 1-hexene epoxidation reaction than the conventional TS-1 zeolite containing only framework Ti species (35 vs 24%). This can be ascribed to the more active hexa-coordinated Ti species and shorter diffusion distance. This synthetic strategy provides a way to change the zeolite morphology and tune the number and distribution of Ti species in TS-1 zeolites.
研究领域:
催化材料
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晶体工程
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化学合成
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
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IF 6.7
Xin Guo,Zhiyuan Wang,Siqi Jiang,Mengwei Li,Jianing Guo,Yu Cui,Xueyang Wei,Baohui Qi,Qizhong Huang,Yanduo Liu,Hongquan Jiang,Yufeng Hu
Photocatalytic technology for converting CO 2 into useful chemicals or clean energy is an effective strategy to solve today's energy and environmental problems. In this study, we present a direct photocatalytic pathway for the conversion of CO 2 -to-CO involving the formation and activation of carboxyl intermediates over amino-functionalized ionic liquid (3-aminopiperidine hydrochloride, [3APip]Cl)-modified titanium silicalite-1 (TS-1) molecular sieve nanosheets . Various in-situ characterizations reveal that the key to activating this pathway lies in the CO 2 adsorption capacity and the efficiency of photoexcited charge migration induced by [3APip]Cl in the hybrid catalyst. In the above catalytic pathway, CO 2 molecules are first adsorbed on the surface of the [3APip]Cl/TS-1 hybrid catalyst under the induction of amino groups in the ionic liquid. Then, these adsorbed CO 2 are activated and transformed into carboxyl intermediate, which can be further converted into CO and CH 4 through photoexcited electrons captured by [3APip]Cl. Based on the results of CO 2 reduction performance, the optimized [3APip]Cl/TS-1 hybrid catalyst achieves a 6-fold increase, and the CO selectivity is 83.0%. This research provides new insights into the CO 2 reduction pathway in mild conditions and emphasizes the importance of the adsorption–activation tandem process for enhancing photoactivity and selectivity.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2022
·
IF 5.876
Saisai Ran,Hanfang Liu,Xiaolong Li,Huijie Xie,Wei Xu,Bin Li,Yu Yang,Yongming Chai,Lei Wang
Utilizing silica-rich wastes for synthesis of zeolite can realize a green production protocol and make best use of solid waste. However, industrial solid wastes usually require a complicated pretreatment process and their surface properties are underestimated for the final products. In this study, silica wastes with different acid or basic surface properties are directly used for the solvent-free synthesis of TS-1 zeolites. The states of Ti species, Si/Ti molar ratios, and morphology of final TS-1 zeolites can be controlled by the pristine surface properties and additional ammonium carbonate. TS-1 zeolite synthesized from acid silica waste exhibits lower crystallinity, abundant highly coordinating titanium species, and an elongated c-axis compared to that from basic silica waste. More importantly, TS-1 zeolite ( n S i / n T i = 30 ) synthesized from silica with acid property possesses excellent performance in the epoxidation of chloropropene with 66.2% conversion and 98.5% selectivity to epichlorohydrin, which is attributed to the presence of abundant high-coordination Ti species of mononuclear TiO 6 . Our strategy provides a novel idea for totally green synthesis of zeolite by utilizing solid wastes.
研究领域:
材料科学
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环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Yulin Yao,Zonghan Yang,Pengfei Zheng,Zhenheng Diao
The accessible TiO 6 concentration and the hydrophobicity of hierarchical TS-1 zeolites are both considered as critical factors for promoting the catalytic performance of selective oxidation. However, simultaneously enhancing these two factors still remains a challenge. Herein, hierarchical TS-1 zeolites with high hydrophobicity and concentration of accessible TiO 6 were fabricated via sequential amphiphilic organosilane-assisted pre-treatment, dry-gel conversion and hydroxyl radical post-treatment, using amphiphilic organosilane and surfactant as meso -porogens. The synthesis mechanism was investigated, and it was found that the interaction between the amphiphilic organosilane and Ti species formed during the pre-treatment benefited the formation of accessible TiO 6 during the subsequent dry-gel conversion. During the post-treatment of zeolite with H 2 O 2 solution under ultraviolet light irradiation, appropriate H 2 O 2 concentration facilitated the generation of hydroxyl radical and thus enhanced the hydrophobicity of zeolite without significantly influencing the TiO 6 concentration. The hierarchical TS-1 displayed excellent catalytic performances in 1-hexene epoxidation and oxidative desulfurization, with conversion improvements of 91.2%±2.8% and 348%±17%, respectively, compared with the conventional counterpart.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Zheng Zhang,Gui-Ping Cao,Qian Cai,Hui Lu,Shuang Ji,Rui Fang,Peng Gao,Miao Feng
The TS-1 particles grown on carbon nanotubes decorated nickel foam (denoted as MTS-1S) are successfully synthesized by a steam-assisted crystallization method that does not waste the gels and is more convenient, economical, and efficient than the traditional hydrothermal method. MTS-1S possesses a hierarchical porous structure of micropores, mesopores, and macropores and a high content of titanium in the skeleton, which is beneficial for the diffusion of reactants and products and exhibits excellent catalytic performance for the epoxidation of propylene. The impact of water on the formation of acid sites has been demonstrated by density functional theory (DFT). The acid sites of MTS-1S can be tuned by controlling the amount of water at the bottom of autoclave during steam-assisted crystallization, which significantly increases the selectivity to propylene oxide. Finally, the impact of acid sites of Si–OH and Ti–OH groups (Ti located in a defect structure, adjacent to Si–OH) on the byreaction of epoxidation of propylene is confirmed by simulation.
研究领域:
催化材料
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
·
IF 8.1
Fei Fan,Shiyu Han,Ying Li,Lu Qi,Jie Kang,Zhiping Chen,Chang Tian,DeChao Wang,Wenwu Zhou
The microenvironments including the surface hydroxyls , the oxygen vacancies , and the d-band center of hierarchical TS-1 zeolite pickled by hydrochloric acid were regulated by ZrO 2 , the effect of ZrO 2 on the physicochemical properties and the catalytic performances of the corresponding NiMoS supported catalysts were studied. The experimental and theoretical calculation results show that the d-band center, the surface hydroxyl groups , and the oxygen vacancies were regulated after incorporation of ZrO 2 . Resulting in the modulated acidity of the support and the metal support interaction of the catalysts, further promoting the formation of type-II NiMoS active phases. The catalytic performance evaluations show that catalyst NiMo/1-ZAT exhibits the superior HDS performance, kinetic study further demonstrated that the enhanced catalytic activity was mainly contributed by the improved direct desulfurization activity generated from the moderate support acidity, suitable MSI, highest sulfidation degrees, most type-II NiMoS active phase and highest activity of individual active sites.
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
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
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IF 22.1
Jiani Zhang,Risheng Bai,Zhaochi Feng,Jiyang Li
Aiming to promote the activity of TS-1 zeolite in catalytic oxidative desulfurization (ODS), a general amide-assisted strategy was proposed to synthesize hierarchical TS-1 zeolite with rich and homogeneously distributed Ti(OH 2 ) 2 (OH) 2 (OSi) 2 species. Strong interactions between acrylamide (AM) and Si/Ti as well as self-polymerization of AM in synthetic gels change the zeolite formation process, thus to effectively construct Ti(OH 2 ) 2 (OH) 2 (OSi) 2 , promote Ti evenly distribution and form micro-mesopore structure. The activity of Ti(OH 2 ) 2 (OH) 2 (OSi) 2 was evaluated by ODS of refractory sulfur-containing compounds. The advantages of Ti(OH 2 ) 2 (OH) 2 (OSi) 2 over TiO 4 in substrate adsorption and reactive intermediate formation for ODS were further proved by theoretical calculations. By adjusting AM amount to optimize the Ti(OH 2 ) 2 (OH) 2 (OSi) 2 content and distribution, the obtained catalyst achieves 134.8 h -1 of turnover frequency and 100 % DBT removal at ten minutes, and maintains > 92 % removal after seven cycles at 333 K. This facile active-site construction strategy is promising to be extended to other heteroatom-containing zeolite catalysts.
研究领域:
催化化学
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材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2024
·
IF 3.5
Ze Zong,Xuliang Deng,Dong Lin,Yang Xu,Qiuming He,Zhe Ma,De Chen,Chaohe Yang,Xiang Feng
Titanosilicate with H 2 O 2 stands out as a highly consequential oxidized catalytic system, prized for its user-friendly operation, mild conditions, and eco-friendly attributes. However, a synthesis strategy for large surface area titanosilicalites approaching the theoretical lowest Si/Ti ratio without extra-framework Ti species remains an ongoing challenge. In this study, we successfully synthesized single-crystalline Ti-rich nanosized aggregated TS-1 by shielding effect with a Si/Ti polymer. This polymer demonstrated effectiveness in restraining TiO 2 species by regulating the proximity of Si/Ti species in Ti-Diol-Si polymers. The polymer not only facilitated the synthesis of single-crystalline Ti-rich TS-1 but also exploited the chain length of PEG, functioning as a shielding cage by hydrogen bonds, to synthesize nanosized aggregated TS-1 (TS-1-PEG400). This TS-1-PEG400 exhibited superior conversion (~60%), selectivity (~90%), and stability in 1-hexene epoxidation. This study not only establishes a synthesis pathway for Ti-rich TS-1 but also holds the potential to enhance related industrial oxidation reactions involving titanosilicates and H 2 O 2 .
研究领域:
催化
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材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）