Department of Engineering, University of Messina, 98122 Messina, Italy.
Sensors (Basel). 2022 Oct 1;22(19):7465. doi: 10.3390/s22197465.
In the present study, the development of a conductometric gas sensor based on Al,Ca-doped zinc oxide composite which is finalized to the detection of formaldehyde (HCHO) at a low concentration in air is investigated. The electrical and sensing properties of the composite based on ZnO doped with different loadings of Al and/or Ca (from 0 up to 5 at%) were evaluated. The gas-sensing mechanism of Al,Ca-doped zinc oxide nanocomposite-based sensors was also discussed. The optimized 3%Al,3%Ca-ZnO sensor displayed a formaldehyde response of 3.5 (@ 4 ppm HCHO/air) and an experimental low detection limit of 125 ppb HCHO/air, at the operating temperature of 400 °C. The sensor was also shown to be selective to HCHO with respect to many interferent indoor gases, but NO changed the baseline resistance in an opposite way compared to the target gas. The developed device for monitoring HCHO in indoor and workplace environments has the advantage of a simple planar structure and can be easily fabricated for mass production by using low-cost materials and easy fabrication methods.
在本研究中，我们开发了一种基于掺铝钙氧化锌复合材料的电导式气体传感器，旨在检测空气中低浓度的甲醛（HCHO）。评估了基于 ZnO 的复合材料的电性能和传感性能，其中 ZnO 掺杂了不同负载量的 Al 和/或 Ca（从 0 到 5 at%）。还讨论了掺铝钙氧化锌纳米复合材料基传感器的气体传感机制。优化后的 3%Al、3%Ca-ZnO 传感器在 400°C 的工作温度下对 4 ppm HCHO/空气的甲醛响应为 3.5，实验检测下限低至 125 ppb HCHO/空气。与许多室内干扰气体相比，该传感器对 HCHO 具有选择性，但与目标气体相比，NO 以相反的方式改变了基线电阻。用于监测室内和工作场所环境中 HCHO 的开发设备具有结构简单的优点，并且可以使用低成本材料和简单的制造方法通过易于制造的方法进行大规模生产。
