Synthesis of Tin Dioxide Octahedral Nanoparticles with Exposed High-Energy {221} Facets and Enhanced Gas-Sensing Properties
Synthesis of Tin Dioxide Octahedral Nanoparticles with Exposed High-Energy {221} Facets and Enhanced Gas-Sensing Properties
复制标题
具有暴露的高能{221}面和增强的气敏性能的二氧化锡八面体纳米粒子的合成
DOI：
10.1002/anie.200903926
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发表时间：
2009-01-01
影响因子：
16.6
通讯作者：
Zheng, Lansun
中科院分区：
文献类型：
--
作者：
Han, Xiguang;Jin, Mingshang;Zheng, Lansun
二氧化锡（SnO 2）是一种n型半导体，具有3.6 eV的宽带隙，广泛应用于有机染料的光催化降解[1]、光伏器件[2]、可充电锂电池[3]等领域。特别是，SnO 2对气体环境变化的敏感性和优异的化学稳定性使其成为最知名的气敏材料。[4-9]在过去的几十年里，人们已经做出了相当大的努力来提高SnO 2基固态气体传感器的灵敏度和选择性，通过修改传感材料本身和制造技术，例如掺杂催化金属颗粒，[4]不同传感材料的杂化，[5，6]和优化工作温度。[7]原则上，通过金属氧化物半导体（如SnO 2）进行的气体感测是基于在半导体表面上发生的被检测气体的氧化还原反应，这导致传感器的电导发生突变。因此，金属氧化物半导体的气敏能力理论上对传感材料的晶面非常敏感。[10]从化学活性的观点来看，具有特定暴露的晶面（例如高折射率小面）的金属氧化物纳米晶体可以是良好的传感材料，因为具有高密度的原子台阶、凸缘、扭结和悬挂键的高折射率小面通常表现出高得多的化学活性。[11-13]然而，这种提高传感器灵敏度和选择性的策略至今尚未引起太多关注，本文报道了一种利用HCl和poly的配位吸附作用制备具有高折射率{221}晶面的八面体SnO 2的简单方法（乙烯基吡咯烷酮），PVP，在溶液中。SnO 2的{221}晶面具有比{221}晶面更高的相对表面能（2.28 Jm 2）。
Tin dioxide (SnO2), an n-type semiconductor with a wide band gap of 3.6 eV, has been widely used in photocatalytic degradation of organic dyes,[1] photovoltaic devices,[2] rechargeable lithium batteries,[3] and so on. In particular, remarkable receptivity to variations in gaseous environments and excellent chemical stability have made SnO2 the bestknown gas-sensing material.[4–9] Over the past decades, considerable efforts have been made to improve the sensitivity and selectivity of SnO2-based solid-state gas sensors through modifying the sensing material itself and the fabrication technique, such as doping of catalytic metal particles,[4] hybridization of different sensing materials,[5, 6] and optimization of working temperature.[7] In principle, gas sensing by metal-oxide semiconductors like SnO2 is based on the oxidation–reduction reaction of the detected gases occurring on the semiconductor surface, which leads to an abrupt change in conductance of the sensor. For this reason, the gas-sensing ability of metal oxide semiconductors is in theory very sensitive to the crystal faces of the sensing materials.[10] From the viewpoint of chemical activity, metaloxide nanocrystals with particular exposed crystal planes, such as high-index facets, may be good sensing materials, because high-index facets having high densities of atom steps, ledges, kinks, and dangling bonds usually exhibit much higher chemical activity.[11–13] However, such a strategy to improve sensitivity and selectivity of sensors has not attracted much attention up to now, possibly due to the difficulty of synthesizing metal-oxide nanocrystals with specific exposed crystal planes.Herein we report a simple method for the preparation of octahedron-shaped SnO2 with exposed high-index {221} facets by exploiting the coordinative-adsorption effect of HCl and poly (vinyl pyrrolidone), PVP, in solution. The {221} facets of SnO2 have a higher relative surface energy (2.28 JmÀ2) than