Highly enhanced gas-sensing properties of indium-doped mesoporous hematite nanowires
Highly enhanced gas-sensing properties of indium-doped mesoporous hematite nanowires
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高度增强的铟掺杂介孔赤铁矿纳米线的气敏性能
DOI：
10.1016/j.jpcs.2018.05.004
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发表时间：
2018-09-01
影响因子：
4
通讯作者：
Wang, X. Q.
中科院分区：
文献类型：
--
作者：
Chen, H. D.;Jin, K. L.;Wang, X. Q.
以介孔SBA-15 SiO2为硬模板，合成了介孔In掺杂的α-Fe 2 O3纳米线，并研究了In掺杂对纳米线结构和气敏性能的影响。通过透射电子显微镜、X射线衍射、紫外-可见光谱和氮气物理吸附实验进行表征，结果表明，平均晶粒尺寸增加至1摩尔% In掺杂剂，然后随着In掺杂剂含量的增加而减小，而表面积以相反的方式变化。由于In的熔点较低，当In含量较低时，In作为助熔剂进入α-Fe 2 O3晶格，平均晶粒尺寸增大。随着In含量的增加，In析出到晶界，晶粒尺寸减小。结果表明，晶格中的In增加了晶格畸变，而晶界处的In增加了比表面积和氧空位，这两种元素都有利于提高气敏性能。In掺杂的α-Fe_2 O_3纳米线的响应比纯的α-Fe_2 O_3纳米线提高了30%~ 50%。基于3 mol% In掺杂的α-Fe 2 O3纳米线的气敏元件在最佳温度下对乙醇具有最佳的气体响应和快速的响应-恢复时间。由于In的同价性，In掺杂只影响α-Fe 2 O3晶格的微观结构和组成，这是改善气敏性能所必需的。
Mesoporous indium (In)-doped hematite (alpha-Fe2O3) nanowires were synthesized with mesoporous SBA-15 silica as a hard template, and then the influence of In dopant on the microstructure and gas-sensing performance was investigated in detail. With characterization by transmission electron microscopy, X-ray diffraction, UV-vis spectroscopy, and nitrogen physisorption experiments, it was shown that the average grain size increased for up to 1 mol% In dopant and then decreased with increasing In dopant content, while the surface area changed in the inverse manner. Because of the low melting point of In, In acted as a fluxing agent and entered the alpha-Fe2O3 lattice when the In content was low, and the average grain size increased. With higher In content, In precipitated out the lattice and existed at the grain boundary, and the grain size decreased. It is concluded that In in the lattice increased lattice distortion and In at the boundary increased the surface area and oxygen vacancies, which were both beneficial for improving the gas-sensing performance. The response of In-doped alpha-Fe2O3 nanowires increased by about 30%-50% as compared with that of pure alpha-Fe2O3 nanowires. The gas sensor based on 3 mol% In-doped alpha-Fe2O3 nanowires exhibited the best gas response and a rapid response-recovery time toward ethanol at the optimum temperature. Owing to the same valence, In dopant affected only the microstructure and components of the alpha-Fe2O3 lattice, which was necessary to improve the gas-sensing behavior.