^(93)Nb核磁共振研究铌酸纳米棒的水热晶化机理  

Hydrothermal Crystallization of Niobium Oxide Nanorods Studied by^(93)Nb Nuclear Magnetic Resonance

作　　者：申长志 张琳琳 李新[1] 申万岭[1] SHEN Changzhi;ZHANG Linlin;LI Xin;SHEN Wanling(College of Chemistry and Chemical Engineering,Henan University of Technology,Zhengzhou 450001,China)

机构地区：[1]河南工业大学化学化工学院,河南郑州450001

出　　处：《波谱学杂志》2023年第4期376-384,共9页Chinese Journal of Magnetic Resonance

基　　金：国家自然科学基金资助项目(21773056,21703056);河南省科技攻关项目(212102210608,202102110289);河南工业大学青年骨干教师项目(0503/21420046,0503/21420110);河南工业大学创新基金支持计划专项资助(2021ZKCJ01)。

摘　　要：氧化铌(Nb_(2)O_(5))及其水合物铌酸(Nb_(2)O_(5)·n H_(2)O)代表了一类重要的多相催化剂,然而其水热合成过程和机理尚不明确.本文采用^(93)Nb NMR,结合X射线粉末衍射、透射电镜等技术和量化计算,研究了以草酸铌铵为前驱体水热生成铌酸纳米棒的晶化过程.结果表明草酸铌铵水热晶化过程中发生了水解-聚合反应,先是草酸铌铵水解,接着铌氧单体之间发生缩水聚合反应,最终生成了层内无序、层间有序结构的固体铌酸纳米棒.晶化过程符合“液相成核”机理,层状结构铌酸纳米棒在180℃下1 h内即可生成,后续水热处理并未使其明显长大,新的固体产物不断由溶液中独立生成.The crystallization process of hydrothermally synthesizing niobium oxide nanorods with ammonium niobium oxalate precursor was investigated using^(93)Nb NMR,combined with X-ray powder diffraction,transmission electron microscopy and quantum chemistry calculations.The results showed that the hydrothermal crystallization of ammonium niobium oxalate underwent a hydrolysis-polymerization reaction,starting with the hydrolysis of ammonium niobium oxalate,followed by the polymerization of the niobium-oxide monomers by condensation,resulting in dimers,trimers and multimers,and finally generating solid niobium oxide nanorods with disordered intra-layer and ordered inter-layer structures.The mechanism of crystallization process is"liquid phase nucleation",with the layer-structured niobium oxide nanorods being produced within 1 h at 180℃.The subsequent hydrothermal treatment does not lead to significant growth of the nanorods,and new solid products are continuously generated independently from the solution.

关 键 词：^(93)Nb核磁共振 纳米氧化铌 草酸铌铵 水热 晶化机理 

分 类 号：O482.53[理学—固体物理]