Acetone sensing properties and mechanism of nano-LaFeO3 thick-films
Acetone sensing properties and mechanism of nano-LaFeO3 thick-films
复制标题
纳米LaFeO3厚膜的丙酮传感特性及机理
DOI：
10.1016/j.snb.2016.05.059
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发表时间：
2016-11-01
影响因子：
8.4
通讯作者：
Hu, Jifan
中科院分区：
文献类型：
--
作者：
Chen, Yanping;Qin, Hongwei;Hu, Jifan
采用Sol-Gel法制备的LaFeO_3纳米晶粉末，经800℃、4h的热处理后，可以灵敏地检测到低浓度的丙酮。当暴露在0.5ppm丙酮中时，LaFeO_3厚膜在260℃下的响应为2.068，响应时间为62 S，恢复时间为107 S。用第一性原理计算研究了LaFeO_3传感器可能的丙酮传感机理。计算结果表明，丙酮能将电子释放到预吸附氧物种O和O-2的LaFeO_3(010)表面。丙酮分子通过以下方式与氧物种反应：(1)吸附在氧物种O-上或(2)取代Fe位上弱预吸附的氧物种O-2(-)，伴随着氧分子的形成。这两个过程可能在丙酮对LaFeO_3的传感中起重要作用。我们还发现丙酮分子可以直接吸附在Fe位上，将一些电子转移到LaFeO_3(010)表面。后一种工艺也可能对丙酮传感做出额外贡献。(C)2016爱思唯尔B.V.保留所有权利。
LaFeO3 nanocrystalline powders prepared by sol-gel method with annealing at 800 degrees C for 4h can sensitively detect low concentration of acetone. When exposed to 0.5 ppm acetone, the response of LaFeO3 thick film at 260 degrees C is 2.068 with response time of 62 s and recovery time of 107 s, respectively. The possible acetone sensing mechanisms for LaFeO3 sensor are investigated with first principles calculations. Calculated results demonstrate that acetone could release electrons to the surface of LaFeO3 (010) pre-adsorbed with oxygen species O and O-2. The acetone molecule reacts with oxygen species in the following ways: (1) adsorbs on oxygen species O- or (2) replaces of the weakly pre-adsorbed oxygen species O-2(-) on Fe site, accompanying the formation of oxygen molecule. These above two processes may play important roles in acetone sensing for LaFeO3. We also find that the acetone molecule can be directly adsorbed on Fe site, transferring some electrons to the LaFeO3 (010) surface. The latter processes may also provide additional contribution to acetone sensing. (C) 2016 Elsevier B.V. All rights reserved.