N-doped Na2Ti6O13@TiO2 core–shell nanobelts with exposed {1 0 1} anatase facets and enhanced visible light photocatalytic performance
N-doped Na2Ti6O13@TiO2 core–shell nanobelts with exposed {1 0 1} anatase facets and enhanced visible light photocatalytic performance
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DOI：
10.1016/j.apcatb.2015.01.026
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发表时间：
2015-07
影响因子：
22.1
通讯作者：
Chao-Jun Liu;Tao Sun;Liang Wu;Ji-yuan Liang;Huang Qianjin;J. Chen;W. Hou
中科院分区：
文献类型：
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作者：
Chao-Jun Liu;Tao Sun;Liang Wu;Ji-yuan Liang;Huang Qianjin;J. Chen;W. Hou
首先将Na2Ti3O7与异丙醇钛混合，然后在空气中用尿素焙烧，成功地合成了N掺杂的Na2Ti6O13@TiO2核壳纳米带。由于Na2Ti6O13中的TiO6八面体更加规则，发生了由Na2Ti3O7相向Na2Ti6O13相的结构演化。由于锐钛矿型TiO2和Na2Ti6O13中TiO6八面体的共同结构特征，在Na2Ti6O13纳米带的外表面沉积了具有特定暴露的{1，0，1}面的锐钛矿型TiO2纳米颗粒，形成了两组分之间紧密接触的界面。还原的{1+0+1}面可能是光生电子的储存库，为O2-O2自由基点−的还原提供了一个高活性的表面，从而降低了光生电子-空穴对的复合速率。得到的复合材料中各向异性形状的钛酸盐纳米带具有较高的载流子迁移率，并为后续反应提供了电荷载流子沿纵向快速传输到不同反应位置的途径。掺杂的N原子主要位于二氧化钛的晶格中，产生可见光响应。由于杂化、形态工程和氮掺杂的综合作用，得到的复合材料在可见光照射下对亚甲基蓝(MB)溶液的光降解表现出很高的稳定性和增强的催化活性。此外，研究还发现，合适的二氧化钛与钛酸盐的质量比和合适的掺杂氮量是获得优异性能的关键。本工作对制备高性能的微细复合光催化剂具有一定的参考价值。
N-doped Na2Ti6O13@TiO2core–shell nanobelts have been successfully synthesized by first mixing Na2Ti3O7with titanium isopropoxide, and then calcinating with urea in air. A structural evolution from the phase Na2Ti3O7to Na2Ti6O13occurred as the TiO6octahedra in Na2Ti6O13is more regular. Anatase TiO2nanoparticles (NPs) with specifically exposed {1 0 1} facets were deposited on the external surface of Na2Ti6O13nanobelts, forming the closely contacted interface between two components due to the common structural features of TiO6octahedra in anatase TiO2and Na2Ti6O13. The reductive {1 0 1} facets could be acted as a possible reservoir of the photogenerated electrons, yielding a highly reactive surface for the reduction of O2–O2radical dot−and thus, lowering the recombination rate of photogenerated electron–hole pairs. The anisotropically shaped titanate nanobelts in the obtained composites possessed a higher charge carrier mobility and provided the pathway for quick transport of charge carriers throughout the longitudinal direction to different reaction sites for subsequent reactions. The doped N atoms were mainly located in the crystal lattices of TiO2, giving rise to the visible light response. Owing to the combined effects of hybridization, morphology engineering, and N doping, the obtained composite showed a high stability and an enhanced catalytic activity for the photodegradation of methylene blue (MB) solution under visible light irradiation. In addition, it was found that both an appropriate mass ratio of TiO2to titanate and a suitable content of doped N were essential for achieving an excellent performance. The present work may provide an insight for the fabrication of delicate composite photocatalysts with a high performance.