Solid state NMR characterization of NaNbO3 and LiNbO3 nanoparticles obtained by microwave-assisted combustion

IF 2.624
Guilherme O. Siqueira , Geraldo M. de Lima , Francielle C. Araújo , Fabrício V. de Andrade , Tiago B. Moraes , Marcos de Oliveira Jr.
{"title":"Solid state NMR characterization of NaNbO3 and LiNbO3 nanoparticles obtained by microwave-assisted combustion","authors":"Guilherme O. Siqueira ,&nbsp;Geraldo M. de Lima ,&nbsp;Francielle C. Araújo ,&nbsp;Fabrício V. de Andrade ,&nbsp;Tiago B. Moraes ,&nbsp;Marcos de Oliveira Jr.","doi":"10.1016/j.jmro.2022.100088","DOIUrl":null,"url":null,"abstract":"<div><p>Nanoparticles of LiNbO<sub>3</sub> and NaNbO<sub>3</sub> were obtained for the first time by microwave-assisted combustion. Preliminary experiments reveal that the synthetic conditions influence their microstructure and optoelectronic features. Therefore, there is a need for performing the structural characterization of these materials, obtained by this new route. In the case of NaNbO<sub>3</sub>, there are two polimorphs which are stable at room temperature, space groups P2<sub>1</sub>ma and Pbma. Powder x-Ray diffraction experiments were not capable to identify the crystalline phases present in the nanoparticles. Therefore, we have performed a detailed structural characterization of the nanoparticles by 1D and 2D solid state <sup>23</sup>Na and <sup>93</sup>Nb Nuclear Magnetic Resonance (NMR) techniques. <sup>23</sup>Na results reveal the presence of both phases, Pbma and P2<sub>1</sub>ma, for samples prepared using NaNO<sub>3</sub> precursor in a 1:1 Na:Nb ratio or NaCl in excess. On the other hand, the P2<sub>1</sub>ma polymorph could be isolated in the synthesis using NaCl salt in 1:1 Na:Nb ratio. On the other hand, LiNbO<sub>3</sub> nanoparticles display the usual rhombohedral structure R3c. <sup>7</sup>Li MAS NMR results reveal the presence of two types of Li species, with distinct dynamics. Highly mobile Li<sup>+</sup> ions are found at the surface of the nanoparticles, while bulk Li<sup>+</sup> show restricted movement. Finally, as a proof of principle, the photocatalytic activity of these niobates was tested for the degradation of methylene blue dye, a common organic-water contaminant.</p></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"14 ","pages":"Article 100088"},"PeriodicalIF":2.6240,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Magnetic Resonance Open","FirstCategoryId":"1","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2666441022000589","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0

Abstract

Nanoparticles of LiNbO3 and NaNbO3 were obtained for the first time by microwave-assisted combustion. Preliminary experiments reveal that the synthetic conditions influence their microstructure and optoelectronic features. Therefore, there is a need for performing the structural characterization of these materials, obtained by this new route. In the case of NaNbO3, there are two polimorphs which are stable at room temperature, space groups P21ma and Pbma. Powder x-Ray diffraction experiments were not capable to identify the crystalline phases present in the nanoparticles. Therefore, we have performed a detailed structural characterization of the nanoparticles by 1D and 2D solid state 23Na and 93Nb Nuclear Magnetic Resonance (NMR) techniques. 23Na results reveal the presence of both phases, Pbma and P21ma, for samples prepared using NaNO3 precursor in a 1:1 Na:Nb ratio or NaCl in excess. On the other hand, the P21ma polymorph could be isolated in the synthesis using NaCl salt in 1:1 Na:Nb ratio. On the other hand, LiNbO3 nanoparticles display the usual rhombohedral structure R3c. 7Li MAS NMR results reveal the presence of two types of Li species, with distinct dynamics. Highly mobile Li+ ions are found at the surface of the nanoparticles, while bulk Li+ show restricted movement. Finally, as a proof of principle, the photocatalytic activity of these niobates was tested for the degradation of methylene blue dye, a common organic-water contaminant.

Abstract Image

微波辅助燃烧制备纳米bo3和LiNbO3纳米颗粒的固体核磁共振表征
采用微波辅助燃烧的方法首次制备了纳米LiNbO3和NaNbO3。初步实验表明,合成条件会影响其微观结构和光电特性。因此,有必要对通过这种新途径获得的这些材料进行结构表征。以NaNbO3为例,存在两种室温稳定的聚晶:P21ma和Pbma空间基团。粉末x射线衍射实验无法识别纳米颗粒中存在的结晶相。因此,我们通过1D和2D固态23Na和93Nb核磁共振(NMR)技术对纳米颗粒进行了详细的结构表征。对于使用NaNO3前驱体以1:1 Na:Nb比或NaCl过量制备的样品,23Na结果显示Pbma和P21ma两相的存在。另一方面,在1:1 Na:Nb比的NaCl条件下,可以分离到P21ma多晶体。另一方面,纳米LiNbO3呈现出常见的R3c菱形结构。7Li MAS NMR结果显示存在两种类型的Li,具有不同的动力学。高流动性的Li+离子在纳米颗粒的表面被发现,而大块Li+表现出有限的运动。最后,作为原理证明,测试了这些铌酸盐对亚甲基蓝染料(一种常见的有机水污染物)的光催化活性。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
CiteScore
1.90
自引率
0.00%
发文量
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信