Pt修饰MoO3纳米线的室温甲醛传感特性研究

Room－temperature formaldehyde gas sensing performance of Pt－decorated MoO_3 nanowire s

采用水热合成技术生长MoO_3纳米线,利用化学还原法在MoO_3纳米线表面进行了Pt纳米颗粒的表面修饰。在室温情况下,检测了Pt/MoO_3纳米线材料对不同浓度甲醛蒸气的传感响应。结果表明,Pt的表面修饰并未对MoO_3纳米线的物相和形貌产生影响。Pt修饰后,利用纳米线所构建的气体传感器的导电性显著提升,电阻值由修饰前的175.75 MΩ降低至53.22 MΩ。气敏测试结果表明,当空气中甲醛体积分数为100×10^(-6)时,器件的响应度约为51.7%,响应时间和恢复时间分别为6.9 s和97.8 s。此外,随着甲醛浓度的增加,响应度和响应时间逐渐增加,恢复时间逐渐降低。这种电阻型甲醛响应主要来自Pt催化下MoO_3表面吸附氧与空气中甲醛分子的氧化还原反应,该过程释放了束缚态电子,使器件电阻显著降低。

In this work,the MoO3 nanowires were synthesized by hydrothermal method,which was decorated by Pt nanoparticles on the surface through chemical reduction method.The sensing response of Pt/MoO3 nanowires to different concentrations of formaldehyde vapor were measured at room temperature.The results show that the Pt-decoration does not change the phase and morphology of the MoO3 nanowires.After the Pt-decoration treatment,the conductivity of the gas sensors is significantly improved.The resistance value is reduced from 175.75 MΩbefore modified to 53.22 MΩ.The gas sensitivity test results show that the sensing response of Pt/MoO3 to 100×10-6 of HCHO is about 51.7%,and the response and recovery time are 6.9 s and 97.8 s,respectively.In addition,as the concentration of formaldehyde increases,the responsibility and response time gradually increase,while the recovery time gradually decreases.Such resistance-type HCHO response could be mainly attributed to the redox reaction between the absorbed oxygen species on the surface of MoO3 and the HCHO molecular under the catalytic effect of Pt nanoparticles,which results in the release of bound electrons and decreases the resistance of the devices.