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Effect of copper on textural and acidic properties of hierarchical nanocrystalline ZSM‐5
Asia-Pacific Journal of Chemical Engineering ( IF 1.8 ) Pub Date : 2020-07-29 , DOI: 10.1002/apj.2547 Farsana O. P 1 , Prajitha Kumari 1 , Aneesh P 2
Asia-Pacific Journal of Chemical Engineering ( IF 1.8 ) Pub Date : 2020-07-29 , DOI: 10.1002/apj.2547 Farsana O. P 1 , Prajitha Kumari 1 , Aneesh P 2
Affiliation
In this work, hierarchically porous nanocrystalline ZSM‐5 was synthesized hydrothermally. Different concentrations of copper were incorporated into the matrix by ion exchange method. The synthesized samples were characterized by means of X‐ray diffraction (XRD), Fourier‐transform infrared (FTIR), energy‐dispersive X‐ray spectroscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy (XPS), ultraviolet (UV), 27Al magic angle spinning nuclear magnetic resonance spectroscopy, and nitrogen sorption analysis. The acid sites on the surface of Cu‐ZSM‐5 have been systematically investigated using temperature‐programmed desorption of ammonia (NH3‐TPD) and pyridine sorption followed by FTIR. The diffraction pattern obtained from XRD studies confirmed the typical Mobil Five. NH3‐TPD reveals the enhancement of acidity achieved by copper. The FTIR spectra of pyridine desorbed samples show that the intensity of bands corresponding to Lewis acidity increases by modification. The ZSM‐5 zeolite samples exhibit spherical‐shaped MFI crystal structure. The UV spectrum indicates that copper has been doped in the form of cations or in the form of oxides. XPS analysis confirms that the copper exists as Cu(I) and Cu(II). The nitrogen sorption isotherms reveal that the modified samples are mesoporous in nature. The pore volume and diameter were found to be enhanced by the modification. The better textural properties and acidic properties of the Cu‐ZSM‐5 can make it suitable for catalyzing organic reactions.
中文翻译:
铜对分层纳米晶体ZSM-5的织构和酸性的影响
在这项工作中,水热合成了分层多孔纳米晶体ZSM-5。通过离子交换法将不同浓度的铜掺入基质中。合成的样品通过X射线衍射(XRD),傅立叶变换红外(FTIR),能量色散X射线光谱,扫描电子显微镜,X射线光电子光谱(XPS),紫外(UV),27 Al魔角旋转核磁共振波谱,以及氮吸附分析。使用程序升温的氨解吸(NH 3 -TPD)和吡啶吸附,再进行FTIR,系统地研究了Cu‐ZSM-5表面的酸位。从XRD研究获得的衍射图证实了典型的美孚5号。NH3- TPD揭示了铜实现的酸性增强。吡啶解吸样品的FTIR光谱表明,相应于路易斯酸度的条带强度通过修饰而增加。ZSM-5沸石样品呈现球形MFI晶体结构。UV光谱表明,铜已经以阳离子形式或氧化物形式被掺杂。XPS分析证实铜以Cu(I)和Cu(II)的形式存在。氮吸附等温线揭示改性样品本质上是中孔的。发现通过改性提高了孔体积和直径。Cu‐ZSM‐5具有更好的质构性质和酸性性质,使其适合催化有机反应。
更新日期:2020-10-06
中文翻译:
铜对分层纳米晶体ZSM-5的织构和酸性的影响
在这项工作中,水热合成了分层多孔纳米晶体ZSM-5。通过离子交换法将不同浓度的铜掺入基质中。合成的样品通过X射线衍射(XRD),傅立叶变换红外(FTIR),能量色散X射线光谱,扫描电子显微镜,X射线光电子光谱(XPS),紫外(UV),27 Al魔角旋转核磁共振波谱,以及氮吸附分析。使用程序升温的氨解吸(NH 3 -TPD)和吡啶吸附,再进行FTIR,系统地研究了Cu‐ZSM-5表面的酸位。从XRD研究获得的衍射图证实了典型的美孚5号。NH3- TPD揭示了铜实现的酸性增强。吡啶解吸样品的FTIR光谱表明,相应于路易斯酸度的条带强度通过修饰而增加。ZSM-5沸石样品呈现球形MFI晶体结构。UV光谱表明,铜已经以阳离子形式或氧化物形式被掺杂。XPS分析证实铜以Cu(I)和Cu(II)的形式存在。氮吸附等温线揭示改性样品本质上是中孔的。发现通过改性提高了孔体积和直径。Cu‐ZSM‐5具有更好的质构性质和酸性性质,使其适合催化有机反应。