Molecular Catalysis
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2024
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IF 3.9
Haoxi Jiang,Hanwen Gu,Lingtao Wang,Guochao Yang
Zr-BEA zeolite was introduced to the aldol condensation of acetaldehyde and showed high crotonaldehyde selectivity (over 85%), but it suffered from rapid deactivation, where the conversion of acetaldehyde decreased from 16.4% at 1 h to 6.5% at 8 h. The spent Zr-BEA zeolites at different time-on-stream (TOS = 1, 2, 4, 6, and 8 h) were characterized by SEM, XRD, XPS, FT-IR, TGA, N 2 physical adsorption, and GC–MS to understand the deactivation mechanism. Pore blocking and Zr active site coverage caused by carbonaceous deposits were both responsible for the deactivation. Furthermore, the main carbonaceous species were unsaturated aldehydes, unsaturated ketones, and aromatic compounds.
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
Molecular Catalysis
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2024
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IF 3.9
Hanwen Gu,Guochao Yang,Lingtao Wang,Haoxi Jiang
Metal-incorporated *BEA zeolites have shown remarkable catalytic performance in the self-aldol condensation of various aldehydes. The substitution of heteroatom sites can modulate the self-aldol condensation performance of aldehydes, while the underlying mechanisms have been insufficiently explored, with even less attention given to acetaldehyde-related processes. Herein, seven transition metal-incorporated *BEA zeolites were post-synthesized and applied in the self-aldol condensation of acetaldehyde. All the M-BEA zeolites exhibited excellent crotonaldehyde selectivity, exceeding 80 % and most surpassing 85 %, with various acetaldehyde conversions. SEM, XRD, N 2 physisorption, FT-IR, UV–Vis, XPS, Py-IR, and NH 3 -TPD were employed to characterize the physicochemical properties. The M-BEA zeolites predominantly exhibit Lewis acidity, and the amount of Lewis acid with medium strength dominated the acetaldehyde conversion variations. The probe-pulse and TPSR experiments were further employed to investigate the reaction pathways to explain the product distribution on the Zr-BEA zeolite, which demonstrated the highest crotonaldehyde yield. The main side products were long-chain unsaturated aldehydes and cyclic compounds from excessive aldol condensation and cyclization. A reaction network for acetaldehyde conversion on Zr-BEA zeolite was ultimately proposed.
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
Catalysis Science & Technology
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2025
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IF 4.2
Yulai Lin,Jun Liang,Zijun Huang,Jiaming Dong,Yongming Luo,Dedong He
Cobalt-based catalysts have garnered significant attention in propane dehydrogenation (PDH) due to their cost-effectiveness and environmental compatibility, where the properties of Co species dictate catalytic performance. However, conventional synthesis methods fail to simultaneously achieve precise encapsulation and structural stabilization of Co sites under harsh PDH conditions. Herein, we propose an innovative dual-anchoring strategy that synergizes strong electrostatic adsorption (SEA) and secondary crystallization (SC) to engineer highly stable yet active Co centers at low metal loadings (0.145 wt%). The SEA process enabled directional anchoring of Co precursors within silanol nests of dealuminated BEA zeolite, while SC treatment prevented Co aggregation. This synergistic approach yielded tetrahedral Co²⁺ (Td-Co²⁺) sites with exceptional dispersion and optimized Lewis acidity, achieving stable PDH operation for 110 hours with specific activity surpassing most reported catalysts.
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 A-GENERAL
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2024
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IF 4.7
Meng Liu,Caixia Miao,Zhijie Wu
The direct synthesis of methyl acetate (MA) from methanol is an appealing and green approach, but an efficient catalyst is urgently needed. Herein, Cu-Ni bimetallic clusters, with a diameter of ∼1.2 nm, have been successfully encapsulated within BEA zeolite by an in-situ two-step encapsulation method (Cu-Ni@Beta), which significantly favors the dispersion of metals compared to the ion-exchanging (Cu/Ni@Beta) and wet impregnation approach (Cu-Ni/Beta). The as-synthesized Cu-Ni@Beta catalyst shows a MA formation rate of 1.46 mmol s −1 g (Cu+Ni) −1 , which is much higher than Cu/Ni@Beta of 0.02 mmol s −1 g (Cu+Ni) −1 and Cu-Ni/Beta of 0.12 mmol s −1 g (Cu+Ni) −1 . Characterization studies reveal that zeolite constraints could not only provide the spatial confinement for metal clusters but also induce an electronic interaction between confined Cu and Ni species in Cu-Ni@Beta. This interaction can increase and stabilize Cu + sites as well as Lewis acid sites, which are crucial for improving catalytic performance. In-situ FTIR experiments indicate that the formation of formaldehyde (CH 2 O*) is the critical step for methanol to MA, and the CH 2 O* further couples with methoxy (CH 3 O*) to form acetate species (CH 3 CHO*), which subsequently couples with CH 3 O* to produce MA.
研究领域:
催化化学
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材料科学
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绿色化学
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产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2022
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IF 5.876
Haoxi Jiang,Shuning Jiang,Debin Kong,Lingtao Wang,Guochao Yang
Metallosilicates with isolated framework metal sites as well as Lewis acidity, e.g., Zr- β zeolite , is proven to be one of the most active for the conversion of ethanol to 1,3-butadiene (ETB), which is a potential process for sustainable butadiene production. However the development process of isolated Zr sites in *BEA framework and their structure–activity relationship in ETB process are still under debate. In this work, three post-synthetic procedures, Liquid Phase Incorporation (LPI), Solid State Ion Exchange (SSIE), and Direct Loading were applied for isolated framework Zr sites development, and the procedure as well as catalytic performance and mechanism were systematically investigated. The isolated framework sites could be developed by Liquid Phase Incorporation (LPI) process, where calcination was the key step for Zr-O-Si bond formation, thus representing Zr incorporation into *BEA framework, accompanying the absence of Zr ion exchange. Isolated Zr framework site was the active site in ETB process, for the strong Lewis acidity upon Zr incorporation. DRIFT and TPSR results revealed that the MPV reduction of crotonaldehyde on Zr site was rate-determining in ETB process.
研究领域:
催化化学
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多相催化
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材料化学
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能源化工
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绿色化学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
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2018
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IF 0
Hailin Xiao,Junliang Wu,Xueqing Wang,Jialing Wang,Shengpeng Mo,Mingli Fu,Limin Chen,Daiqi Ye
Deep catalytic oxidation of toluene in low concentrations by ozone on a supported Pt-Ce/BEA catalyst using a facile preparation method was investigated. The catalyst was prepared using a simple grinding and calcination process, and then characterized by inductively coupled plasma elemental analysis, X-ray diffraction, transmission electron microscopy, H 2 temperature programmed reduction, O 2 and toluene temperature programmed desorption, and ultraviolet Raman spectroscopy. The characterization results showed that Pt nanoparticles and CeO 2 intimately contacted on the surface of the catalyst, and a strong interaction occurred between them. The catalyst was employed for toluene oxidation with ozone because a strong interaction occurs between the Pt NPs and CeO 2 . We aimed to investigate the interaction between the Pt NPs and CeO 2 ; thus, we compared the three catalysts. Pt-Ce/BEA exhibited superior catalytic performance (>99% toluene conversion and >99% CO 2 selectivity at 90 °C) compared to Pt/BEA (85% toluene conversion and 63% CO 2 selectivity) and Ce/BEA (>99% toluene conversion and 59% CO 2 selectivity). The strong interaction between the Pt nanoparticles and CeO 2 increased the amount of oxygen vacancy and thus improved the ozone decomposition activity, which yielded more active oxygen species and contributed to the toluene oxidation.
研究领域:
环境催化
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大气污染控制
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纳米催化材料
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表面化学
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多相催化
✓ 已验证
DOI
危险品化学品经营许可证（带存储）