Small
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2024
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IF 13
Rui Liu,Hao Wu,Hoi Ying Chung,Wahyu Prasetyo Utomo,Yuanmeng Tian,Jin Shang,Patrick H.-L. Sit,Yun Hau Ng
Rationally designing photocatalysts is crucial for the solar-driven nitrogen reduction reaction (NRR) due to the stable N≡N triple bond. Metal-organic frameworks (MOFs) are considered promising candidates but suffer from insufficient active sites and inferior charge transport. Herein, it is demonstrated that incorporating 3 d metal ions, such as zinc (Zn) or iron (Fe) ions, into Al-coordinated porphyrin MOFs (Al-PMOFs) enables the enhanced ammonia yield of 88.7 and 65.0 µg g cat −1 h −1 , 2.5- and 1.8-fold increase compared to the pristine Al-PMOF (35.4 µg g cat −1 h −1 ), respectively. The origin of ammonia (NH 3 ) is verified via isotopic labeling experiments. Incorporating Zn or Fe into Al-PMOF generates active sites in Al-PMOF, that is, Zn-N 4 or Fe-N 4 sites, which not only facilitates the adsorption and activation of N 2 molecules but suppresses the charge recombination. Photophysical and theoretical studies further reveal the upshift of the lowest unoccupied molecular orbital (LUMO) level to a more energetic position upon inserting 3d metal ions (with a more significant shift in Zn than Fe). The promoted nitrogen activation, suppressed charge recombination, and more negative LUMO levels in Al-PMOF( 3d metal) contribute to a higher photocatalytic activity than pristine Al-PMOF. This work provides a promising strategy for designing photocatalysts for efficient solar-to-chemical conversion.
研究领域:
材料科学
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化学工程
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能源转换
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS RESEARCH BULLETIN
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2013
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IF 1.913
Weiya Huang,Dan Li,Yi Zhu,Kai Xu,Jianqiang Li,Boping Han,Yuanming Zhang
In this study, Al(III)-coordinated diamino-functionalized macroporous–mesoporous silica was synthesized and characterized by X-ray diffraction, N 2 adsorption–desorption, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy. Because of well-defined and interconnecting macroporous–mesoporous networks, the resulting adsorbent (MM-SBA) exhibited a significantly better phosphate adsorption performance and faster removal rate, as compared with the mesoporous adsorbent (M-SBA). Based on the Freundlich and Langmuir models, the phosphate adsorption capacity and the maximum adsorption capacity of MM-SBA were 7.99 mg P/g and 23.59 mg P/g, respectively. In the kinetic study of MM-SBA, over 95% of its final adsorption capacity reached in the first 1 min; whereas that of M-SBA was less than 79%.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry Letters
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2024
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IF 4.8
Xue Zhou,Yueying Chu,Chao Wang,Qiang Wang,Min Hu,Jun Xu,Feng Deng
γ-Al2O3 is a crucial catalyst widely used in industrial alcohol dehydration processes. However, the specific nature of its active sites has remained unclear. In this study, we utilize two-dimensional heteronuclear correlation solid-state nuclear magnetic resonance and density functional theory calculations to uncover the active Al sites on the surface of γ-Al2O3 that facilitate ethanol dehydration. We show the formation of stable pentacoordinated AlV–ethanol complexes upon the adsorption of ethanol on the tetracoordinated AlIV sites. This interaction significantly enhances synergy with adjacent AlV–OH sites, resulting in a marked reduction of the activation energy barrier for ethene production. Furthermore, we reveal an interchange between AlIV and AlV–OH species, allowing hexacoordinated AlVI–OH sites to participate in the dehydration pathway through the migration of ethanol between these coordination sites.
研究领域:
催化化学
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物理化学
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固态核磁共振光谱
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密度泛函理论
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表面化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Qin Wu,Chi Fan,Ya Wang,Xiaoping Chen,Guimin Wang,Zhengxing Qin,Svetlana Mintova,Junhua Li,Jianjun Chen
The reduction of NO x emission during the cold start period of diesel vehicles requires special attention in accordance with the emission regulations. In this work, the direct incorporation of cerium and copper in SAPO-18 catalyst with AEI type framework structure (CuCe-SAPO-18) resulting in a substantial enhancement of the performance in the low-temperature NH 3 -SCR reaction (<200 ℃). A small amount of cerium (0.13–0.31 wt%) broadened the reaction temperature range of use and increased the hydrothermal stability of the catalyst considerably. The cerium species was introduced in the ion-exchange sites of Cu-SAPO-18 in the form of Ce 3+ ions even with high loading (3.15 wt%). The Ce 3+ ions were found to affect the distribution of silicon and aluminum atom coordination ( 29 Si NMR, 27 Al MAS NMR) in the AEI-type skeleton structure leading to an increase of both the amount of active Cu 2+ species and the acidity of the CuCe-SAPO-18 catalysts that are beneficial for the NH 3 -SCR reaction.
研究领域:
催化化学
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环境科学
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材料化学
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大气污染控制
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无机固体化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2025
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IF 3.9
Ketao Shi,Youbing Zhu,Zhen Xu,Nianming Jiao,Hui Wang
The metal coordination state and the corresponding acid property of zeolite closely relate to its catalytic performance. In this study, DBD-plasma (dielectric barrier discharge-plasma), a low-temperature and energy-efficient external activation method, was proposed to activate the NH4+-type ZSM-5 zeolite and to regulate the Al coordination. It was found that DBD treatment could efficiently decompose NH4+ species at 115 °C, far below that required for calcination (550 °C). Characterizations, including X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), 27Al magic angle spinning nuclear magnetic resonance (27Al MAS NMR), and pyridine-adsorption infrared spectroscopy (Py-IR), revealed that DBD-plasma treatment could inhibit zeolite framework destruction and retain more framework Al and mesoporous structure, thus improving the stability and enhancing the amount of medium-strong Brønsted acid sites. In n-hexane cracking, DBD-activated zeolite exhibited improved conversion and C2–C4 olefin selectivity due to the enhanced monomolecular cracking pathway induced by increased Brønsted acidity, while reducing aromatics and coke formation by suppressing side reactions. This paper presents an alternative method that is more energy-efficient, highly effective, and capable of regulating the metal coordination and acidity of ZSM-5 zeolite.
研究领域:
催化
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材料科学
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化学工程
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
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