Characterization of Chromium Cations in CrAPO-5 Metal Aluminophosphate

IF 2.4 4区材料科学 Q2 CRYSTALLOGRAPHY

Crystals Pub Date : 2024-08-26 DOI:10.3390/cryst14090758

Sergei A. Zubkov, Elena D. Finashina, Valery N. Zakharov, Leonid Kustov

引用次数: 0

Abstract

Chromium-substituted aluminophosphate (CrAPO-5) with the AFI crystal structure was prepared for the first time by using microwave conditions at the stage of gel formation and crystallization. This approach allowed the reduction of the time required for the synthesis of CrAPO-5 from 60–70 h to 6 h. CrAPO-5 metal aluminophosphate prepared by microwave-assisted synthesis is studied by UV-visible and IR spectroscopy and X-ray photoelectron spectroscopy. The material is characterized by the presence of Cr3+ and Cr2+ ions in the framework with predominating Cr3+ ions introduced via isomorphous substitution, as well as some minor amounts of extra-framework Cr3+ species, which are present presumably in the state of α-Cr2O3. The latter species can be partially reduced to Cr2+ species in the presence of CO or H2. XPS study of CrAPO-5 revealed the presence of Cr3+ ions in the framework. A TPR experiment showed that the reduction of chromium starts at about 450–500 °C.

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CrAPO-5 金属铝磷酸盐中铬阳离子的表征

首次在凝胶形成和结晶阶段利用微波条件制备了具有 AFI 晶体结构的铬代磷酸铝（CrAPO-5）。微波辅助合成法制备的 CrAPO-5 金属铝磷酸盐通过紫外-可见光谱、红外光谱和 X 射线光电子能谱进行了研究。该材料的特征是框架中存在 Cr3+ 和 Cr2+ 离子，其中主要的 Cr3+ 离子是通过同构取代的方式引入的，此外还存在少量的框架外 Cr3+ 物种，它们可能以 α-Cr2O3 的状态存在。后者在 CO 或 H2 的存在下可部分还原为 Cr2+ 物种。对 CrAPO-5 的 XPS 研究表明，框架中存在 Cr3+ 离子。TPR 实验表明，铬在大约 450-500 °C 时开始还原。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Crystals CRYSTALLOGRAPHYMATERIALS SCIENCE, MULTIDIS-MATERIALS SCIENCE, MULTIDISCIPLINARY

CiteScore

4.20

自引率

11.10%

发文量

1527

审稿时长

16.12 days

期刊介绍： Crystals (ISSN 2073-4352) is an open access journal that covers all aspects of crystalline material research. Crystals can act as a reference, and as a publication resource, to the community. It publishes reviews, regular research articles, and short communications. Our aim is to encourage scientists to publish their experimental and theoretical results in as much detail as possible. Therefore, there is no restriction on article length. Full experimental details must be provided to enable the results to be reproduced. Crystals provides a forum for the advancement of our understanding of the nucleation, growth, processing, and characterization of crystalline materials. Their mechanical, chemical, electronic, magnetic, and optical properties, and their diverse applications, are all considered to be of importance.