Humidity-Mediated QCM Sensor Based on COF-5 for Carbon Dioxide Detection
Xiaoyi Xu, Linwei He, Shuang Cao, Bing Yu, Ning Sui, Duo Zhang, Tingting Zhou, Tong Zhang
Abstract
In this work, covalent organic frameworks (COF-5) are synthesized based on the dehydration reaction of organic ligands and serve as the sensitive layers to realize the reliable detection of CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . The as-prepared COF-5 based quartz crystal microbalance (QCM) sensor shows a humidity-enhanced CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> response. Under 80% RH, the response to 8000 ppm CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is 154 Hz at room temperature. In addition, the sensor also shows the great selectivity and repeatability. The large specific surface area and -OH group of COF-5 provide the great platform for the adsorption/desorption of CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> molecules on the sensitive membrane surface. This work paves the way for rational design of QCM CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> sensors with the high performances.