iScience
·
2021
·
IF 5.458
Mingwei Weng,Zihao Zhang,Francis Okejiri,Yue Yan,Yubing Lu,Jinshu Tian,Xiuyang Lu,Siyu Yao,Jie Fu
Catalytic transfer hydrogenation (CTH) of biomass-derived furfural (FAL) to furfuryl alcohol is recognized as one of the most versatile techniques for biomass valorization. However, the irreversible sintering of metal sites under the high-temperature reaction or during the coke removal regeneration process poses a serious concern. Herein, we present a silicalite-1-confined ultrasmall CuO structure (CuO@silicalite-1) and then compared its catalytic efficiency against conventional surface-supported CuO structure (CuO/silicalite-1) toward CTF of FAL with alcohols. Characterization results revealed that CuO nanoparticles encapsulated within the silicalite-1 matrix are ∼1.3 nm in size in CuO@silicalite-1, exhibiting better dispersion as compared to that in the CuO/silicalite-1. The CuO@silicalite-1, as a result, exhibited nearly 100-fold higher Cu-mass-based activity than the CuO/silicalite-1 counterpart. More importantly, the activity of the CuO@silicalite-1 catalyst can be regenerated via facile calcination to remove the surface-bound carbon deposits, unlike the CuO/silicalite-1 that suffered severe deactivation after use and cannot be effectively regenerated.
研究领域:
化学工程
·
材料科学
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DOI
PubMed
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2026
·
IF 9.2
Ubong J. Etim,Peng Bai,Waheed Iqbal,Ziyi Zhong
Supported palladium (Pd) catalysts are known for their exceptional catalytic activity in methane combustion; however, they often undergo rapid deactivation due to sintering under practical reaction conditions. This study aims to develop highly active and stable catalysts for CH 4 combustion by investigating the effect of guest elements within silicalite-1 (S-1) zeolite as supports for Pd. Various transition metals (TMs) were introduced into the S-1 gel to modify its structural properties. The TMs were incorporated into both framework and extra-framework positions, as demonstrated for iron (Fe) and titanium (Ti), resulting in the formation of FeS-1 and TS-1, respectively. The structures were confirmed by Fourier transform infrared (FTIR) and ultraviolet-visible diffused reflectance (UV-vis DR) spectroscopy. Following Pd impregnation, the resulting Pd/FeS-1 and Pd/TS-1 exhibited high activity in CH 4 combustion. Compared to 1Pd/S-1, both 1Pd/FeS-1 and 1Pd/TS-1 achieved excellent low-temperature catalytic performance (T 90 < 400 °C), along with high reaction rates, turnover frequency (TOF) and stability. Characterization of the catalysts confirms the stabilizing effects of Fe and Ti on Pd species, primarily attributed to the formation of PdO x nanoclusters. Fe 3+ maintained PdO x in a more oxidized state, facilitated the activation of gas-phase oxygen, and provided anchoring sites for CH 4 activation into CH 3 ∗ , which combined with activated oxygen species. The reaction follows the Langmuir-Hinshelwood (L-H) mechanism, in which both CH 4 and oxygen are first adsorbed on the catalyst surface. Adsorbed and activated CH 4 species are sequentially oxidized by active oxygen species, leading to the formation of chemisorbed CO species, which are transformed into CO 2 and H 2 O as the final products.
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高影响因子
Catalysts
·
2019
·Vol. 9
·期 8
·672
·
IF 3.444
Xinya Pei,Xiaoxue Liu,Xiaoyu Liu,Jinling Shan,Hui Fu,Ying Xie,Xuemin Yan,Xianzhu Meng,Yancheng Zheng,Geng Li,Qi Wang,Hao Li
Hierarchical titanium silicalite-1 (HTS-1) zeolites are an important class of catalytic materials due to their enhanced mass transfer and improved catalytic performance. In this study, HTS-1 zeolites have been successfully prepared by the hydrothermal crystallization of carbon-silica-titania (CST) composites. Compared with the direct carbonization method, the mild carbonization of SiO2-TiO2/Tween 40 xerogel in the presence of sulfuric acid can effectively improve both the content and mesoporous structure of carbon material in the CST composites, which enables carbon materials to better play the role of a mesoporous template during the crystallization process. The resultant zeolite has both ordered micropores and interconnected mesopores and macropores, which are similar to the skeleton of the carbon template trapped in the TS–1 crystals. Moreover, the HTS–1 zeolite displays outstanding catalytic performance in oxidative desulfurization of bulky sulfur compounds.
研究领域:
材料科学
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催化化学
·
纳米多孔材料
·
环境催化
·
能源化工
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DOI
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Qian Zhao,Changzhong Liao,Guangyuan Chen,Ruixi Liu,Zeru Wang,Anhu Xu,Shiyin Ji,Kaimin Shih,Lin Zhu,Tao Duan
Effective capture of radioactive iodine is highly desirable for decontamination purposes in spent fuel reprocessing. Cu-based adsorbents with a low cost and high chemical affinity for I2 molecules act as a decent candidate for iodine elimination, but the low utilization and stability remain a significant challenge. Herein, a facile in situ confined synthesis strategy is developed to design and synthesize a copper-encapsulated flaky silicalite-1 (Cu@FSL-1) zeolite with a thickness of ≤300 nm. The maximum iodine uptake capacity of Cu@FSL-1 can reach 625 mg g–1 within 45 min, which is 2 times higher than that of a commercial silver-exchanged zeolite even after nitric acid and NOX treatment. The Cu nanoparticles (NPs) confined within the zeolite exert superior iodine adsorption and immobilization properties as well as high stability and fast adsorption kinetics endowed by the all-silica zeolite matrix. This study provides new insight into the design and controlled synthesis of zeolite-confined metal adsorbents for efficient iodine capture from gaseous radioactive streams.
研究领域:
材料科学
·
环境科学
·
核能工程
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DOI
高影响因子
ChemCatChem
·
2026
·Vol. 18
·期 12
·e70879
·
IF 4.1
Minjie Hu,Chan Wu,Hui Yue,Sichun Yang,Xu Hou,Enxian Yuan,Jiancheng Zhou
Dry reforming of methane (DRM) offers a promising route to convert greenhouse gases into syngas, although fabricating Ni-based catalysts with long-term stability during reaction conditions remains challenging. Unlike the conventional H 2 pretreatment typically required for activating Ni-based catalysts prior to DRM, we herein reported a one-pot hydrothermal encapsulation strategy to directly synthesize Ni-Mo bimetallic catalysts confined within silicalite-1 (Ni x Mo@S-1) under CH 4 /CO 2 atmosphere for catalyst activation. In contrast to the conventional impregnation Ni 5 Mo/S-1 catalyst, this structural encapsulation approach effectively improved nickel dispersion and enhanced catalytic performance. XRD and TEM revealed that the encapsulated Ni 5 Mo@S-1 exhibited ultra-small nanoparticle size (∼2.3 nm) and Mo promoted high dispersion of Ni nanoparticles. Furthermore, XPS and XANES confirmed that Ni 5 Mo@S-1 facilitated the direct reduction of NiO to metallic Ni under CH 4 /CO 2 atmosphere, thereby inducing active Ni 0 sites and Ni-O-Si bond formation with reinforced metal-support interaction. Graphical The CH 4 /CO 2 atmosphere-induced strategy of encapsulation of Ni x Mo@S-1 enhances DRM performance. Pretreatment with different atmosphere revealed the distinct roles of CH 4 /CO 2 in fabricating the confinement structure of Ni 5 Mo@S-1 for DRM. The CH 4 /CO 2 pretreatment atmosphere directly drives the formation of both active Ni 0 and stabilizing Ni─O─Si bonds with the promotion of Mo, remarkably reinforcing metal-support interaction.
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高影响因子
INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Ting Yang,Zheng Chen,Ziqing Wang,Jiayuan Yu,Changjiu Xia,Hongxia Liu,Lei Liu,Xinxin Peng,Yibin Luo,Xingtian Shu
Disulfide is an important organic reagent and synthetic intermediate that is widely used in organic synthesis, polymers, and other fields, but its synthesis still suffers from many environmental pollution and economic problems. Here, we present an environmentally friendly and efficient base-free aerobic oxidative thiol coupling catalyzed by heterogeneous CoOx nanoclusters entrapped in hierarchical silicalite-1 zeolite, synthesized by combining silane pore expansion and metal coordination methods under hydrothermal conditions. It is confirmed that open hierarchical channels favor mass diffusion, and the chemical valence of Co species in CoOx/h-S-1-H is +2, which is different from that of Co3O4 particles in CoOx/h-S-1-I. CoOx nanoclusters, are strongly fixed in the channels of silicalite-1 zeolite via Co−O−Si bonds, which is of great importance for the high catalytic activity in both symmetrical and unsymmetrical oxidative thiol coupling reactions. After recycling experiments four times, the CoOx/h-S-1-H used has almost the same chemical state and the same distribution of Co(II) species as the fresh catalysts. Based on DFT calculations and inhibition experiments, the oxidative coupling of thiols undergoes a free radical mechanism in which Co(III) causes RS−H cleavage into RS· and H· species. Subsequently, two RS· radicals are coupled to disulfides, while H· radicals react with the O species to form H2O molecules. This work not only provides guidance on catalyst design and parameter optimization for oxidative thiol coupling but also advances the understanding of the aerobic oxidation mechanism.
研究领域:
催化
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材料科学
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有机化学
·
环境化学
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DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
·
IF 4.8
Wei Chen,Pengfei Wang,Weike Jia,Huidan Zeng
Improving the zeolite adsorption separation efficiency of individual xylene isomer with high purity from their mixture is still a pressing challenge in the fine chemical industry. Herein, plate-like silicalite-1 (p-S-1) zeolite crystals with short b-axis thickness have been successfully synthesized by combination of tributylphosphine oxide (TBPO) modifier and F − -assisted crystallization method to first investigate the separation property of xylene isomers. The morphology and structure of the p-S-1 zeolite crystals were characterized by XRD, FTIR, BET, SEM and TEM. The results showed that the p-S-1 zeolite crystals with thickness of about 50 nm along the b-axis and high crystallinity, as well as extremely rich micropores, were obtained by crystallizing the gels with TBPO/SiO 2 ≥ 0.04. By static adsorption experiment and fixed bed experiment, xylene isomers selective adsorption separation property of the p-S-1 zeolite crystals prepared at TBPO/SiO 2 = 0.04 was investigated. The static adsorption experiment demonstrated that the p-S-1 zeolite crystals exhibited higher adsorption capacity of p-xylene (p-X) and more excellent xylene isomers separation performance than that of the bulk coffin-shaped silicalite-1 (c-S-1) zeolite crystals because of the shorter mass transfer channel and larger diffusivity differences between p-X and o-X/m-X/EB. The dynamic adsorption experiment in simulated five-component solutions diluted by isooctane (IO) indicated that the p-S-1 zeolite crystals had excellent xylene isomers selective adsorption separation performance. The optimum dynamic xylene isomers selective adsorption separation factors for p-X/o-X, p-X/m-X and p-X/EB were 25.41, 36.45 and 11.57 at 150 °C, respectively. The regeneration experiment also indicated that the p-S-1 zeolite crystals had more stable structure and longer lifetime. This work suggested that the p-S-1 zeolite crystals had great potential as new adsorbent for selective adsorption separation of xylene isomers.
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
INTEGRATED FERROELECTRICS
·
2021
·
IF 0.836
Chao Ge,Xiaofeng Li,Zhou Zhao,Zhifeng Yan,Dandan Lian,Jianjun Lu
Silicalite-1 nanosheets catalyst with a hierarchical architecture was hydrothermally synthesized using [C18H37-N+(CH3)2-C6H12-N+(CH3)2-C6H13](Br)−2 as template. It has been studied systematically by investigating the influence of different synthesis parameters and crystallization kinetics under tumbling conditions. Highly crystalline silicalite-1 nanosheets with large external surface was obtained by regulating the crystallization time and the amount of water, template and the alkalinity. It was examined as catalyst for vapor-phase Beckmann rearrangement of cyclohexanone oxime to caprolactam and exhibited an excellent catalytic performance and long catalytic lifetime. This can be attributed to nest silanol groups located on the large external surface of the nanosheets. Furthermore, the high mesoporosity of nanosheets shorten the diffusion path length and reduce coking deposition, which remarkably improve catalyst stability.
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高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2020
·
IF 1.687
Jiang Gao,Lin Gao,Baoqiang Zhang,Haoyu Wang,Weihua Ma
Titanium silicalite-1 (TS-1) has unique catalytic properties for oxidation reactions due to the titanium atom in the framework. To increase the Ti content in the framework, polyvinylpyrrolidone (PVP) was added as a surfactant to modify TS-1 (PTS-1). The titanium content in PTS-1 as the active site in the catalytic reaction increased to 0.87 wt%, compared with the traditional TS-1 which has a titanium content of 0.64 wt%. Simultaneously, the average particle size of PTS-1 is reduced to 180 nm, compared with TS-1 (230 nm). The increase in Ti content makes the Au loading increase; thus, Au/PTS-1 shows higher catalytic performance for propylene epoxidation, and the propylene oxide (PO) formation rate increases from 95 g PO h −1 kg Cat −1 with Au/TS-1 to 190 g PO h −1 kg Cat −1 with Au/PTS-1. In addition, the mechanism for the modification of Ti content by PVP is proposed.
研究领域:
材料科学
·
催化化学
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高影响因子
Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 26
·14710-14721
·
IF 12.732
He Huang,Wanyue Ye,Caicheng Song,Yingcen Liu,Xiaotong Zhang,Yu Shan,Yuzhen Ge,Shufen Zhang,Rongwen Lu
The selective oxidation of primary carbon–hydrogen bonds in the methyl group of toluene to corresponding oxygenates is of immense significance. This transformation, however, remains challenging and often requires either extensive optimization of the present chemical operating processes or, more importantly, the design and development of novel catalysts. In this paper, we achieve the confinement of uniform Au nanoparticles by using Silicalite-1 (Au@Silicalite-1) via an improved impregnation method for solvent-free oxidation of toluene by oxygen to benzaldehyde. In situ Ar+ etching XPS experiments revealed that in the evolution of Au0 and Au3+ species in a single Au@Silicalite-1 crystal the proportion of the Au3+ species becomes enriched from 0 on the surface to >80% in the center. In the synergetic catalysis between Au0 and Au3+ species, it was observed that the electron-rich Au0 species activated oxygen to form superoxide anion radicals, while the electron-deficient Au3+ species promoted activation of the primary carbon–hydrogen bond in toluene and enabled efficient desorption of the desired product benzaldehyde with selectivity >90%. For comparison, Silicalite-1 or SiO2 supported Au0-rich catalysts exhibited strong adsorption of benzaldehyde, generating overoxidized benzoic acid as the main product.
研究领域:
化学工程
·
材料科学
·
催化化学
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DOI
高影响因子
CATALYSIS LETTERS
·
2019
·Vol. 149
·期 4
·974-984
·
IF 2.372
Zhang Xiaotong,He Ning,Liu Chunyan,Guo Hongchen
Highly dispersed Pt–Cu alloy nanoparticles encapsulated in silicalite-1 were prepared by one-pot method. Taking propane dehydrogenation as a probe reaction, it was found that anti-coke ability was improved by encapsulation. Through H 2 -TPR, CO adsorption DRIFT spectra and X-ray Photoelectron Spectroscopy experiment, enhanced anti-coke ability was ascribed to the electronic environment change of encapsulated metal. And it was further confirmed by in situ coking experiment. Owning to limited acidity, metal encapsulated by silicalite-1 molecular sieve exhibited better anti-coke ability and higher propylene selectivity than that by stronger acidic ZSM-5 molecular sieve. Moreover it was found that the combination of Cu and Pt made better catalytic performance and accelerated dehydrogenation more effectively compared with monometallic catalysts. Therefore, Pt–Cu alloy nanoparticles encapsulated in silicalite-1 molecular sieve core–shell material was a potential coke-resistant catalyst for alkane dehydrogenation reaction. Graphical Abstract
研究领域:
催化化学
·
材料科学
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DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Ruyue Niu,Pengcheng Liu,Wei Li,Shuang Wang,Jinping Li
0.123%Pd encapsulated in nanosized silicalite-1 (MFI) zeolite catalysts has been prepared by direct hydrothermal conditions, and its catalytic performance at the low concentration methane combustion was studied. The temperatures for methane ignition ( T 10% ), the half-conversion temperature ( T 50% ) and the total conversion temperature ( T 90% ) over Pd/S-1-in (in-situ method) catalyst are 261, 329 and 382 °C, respectively, which are lower than the corresponding temperatures of Pd/S-1-im (incipient impregnation method) catalyst. Moreover, the properties are further enhanced by introducing CeO 2 into the Pd/S-1-in catalyst. The conversion rate decreased slightly from 91 to 85% when the reaction is carried out at 450 °C for 100 h at the gas hourly space velocities (GHSV) of 112500 mL g −1 h −1 . The XPS analysis showed that Pd clusters were encapsulated within the porous rather than on the surface of the crystal by in-situ method. The HRTEM studies demonstrated that the Pd particle encapsulated within Silicalite-1 zeolites are well dispersed and evenly distributed throughout the Silicalite-1 zeolites. The average size of in situ Pd particle encapsulated in Silicalite-1 zeolite is 1.7 nm, which is much smaller than the impregnated Pd/S-1-im catalyst (2.8 nm).
研究领域:
化学工程
·
环境科学
·
材料科学
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高影响因子
危险品化学品经营许可证（带存储）