Department of Electrical and Computer Engineering, George Washington University, 800 22nd Street, NW, Washington, DC 20052, USA.
Centre for Advanced Materials Processing, CSIR-Central Mechanical Engineering Research Institute, Durgapur-, 713209, India.
Chempluschem. 2019 Apr;84(4):387-391. doi: 10.1002/cplu.201900036.
A semiconducting metal oxide (SMO) chemiresistor (ZnFe O ) is used for discriminating two isomeric volatile organic compounds (VOCs), namely 1- and 2-propanol. The transient current of the SMO chemiresistor is correlated with the aerobic oxidation of organic vapors on its surface. The changes in transient current of the ZnFe O chemiresistor are measured at different temperatures (260-320 °C) for detecting equal concentrations (200 ppm) of the two structural isomers of propanol. The transient current of ZnFe O reflects a faster oxidation of 2-propanol than 1-propanol on the surface. First-principles calculations and kinetic studies on the interaction of 1- and 2-propanol over ZnFe O provide further insight in support of the experimental evidence. The calculations predict more spontaneous adsorption of 2-propanol on the (111) surface of ZnFe O than 1-propanol. Kinetic parameters for the oxidation of isomeric vapors are estimated by modelling the transient current of ZnFe O using the Langmuir-Hinshelwood reaction mechanism. The faster oxidation of 2-propanol and comparatively lower activation energy for the respective process over ZnFe O is justified in accordance to the chemical structures of vapors. The findings have strong implications in exploring a new technique for discriminating isomeric VOCs, which is significant for environmental monitoring and medical applications.
一种半导体金属氧化物（SMO）化学电阻（ZnFe O ）用于区分两种同分异构体挥发性有机化合物（VOCs），即 1-和 2-丙醇。SMO 化学电阻器的瞬态电流与表面上有机蒸气的有氧氧化有关。在不同温度（260-320°C）下测量 ZnFe O 化学电阻器的瞬态电流，以检测两种丙醇结构异构体的相等浓度（200ppm）。ZnFe O 的瞬态电流反映了表面上 2-丙醇比 1-丙醇更快的氧化。ZnFe O 上 1-和 2-丙醇相互作用的第一性原理计算和动力学研究为实验证据提供了进一步的支持。计算预测，2-丙醇在 ZnFe O 的（111）表面上的自发吸附比 1-丙醇更自发。通过使用 Langmuir-Hinshelwood 反应机制对 ZnFe O 的瞬态电流进行建模，估算了异构蒸气氧化的动力学参数。2-丙醇的快速氧化和相应过程在 ZnFe O 上的较低活化能符合蒸气的化学结构。这些发现对探索区分同分异构体 VOCs 的新技术具有重要意义，这对于环境监测和医疗应用具有重要意义。
