Template Free Synthesis of Hollow Ball-Like Nano-Fe2O3 and Its Application to the Detection of Dimethyl Methylphosphonate at Room Temperature

• Published in: Sensors (Basel, Switzerland) Vol. 12; no. 4; pp. 4594 - 4604
• Main Authors: Fan, Guokang, Wang, You, Hu, Meng, Luo, Zhiyuan, Zhang, Kaihuan, Li, Guang
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.04.2012; Molecular Diversity Preservation International (MDPI)
• Subjects: dimethyl methylphosphonate (DMMP); gas sensor; nano-Fe2O3; quartz crystal microbalance (QCM); Scanning electron microscopy; Sensors; China; gas sensor; nano-Fe2O3; dimethyl methylphosphonate (DMMP); quartz crystal microbalance (QCM)
• DOI: 10.3390/s120404594
• ISSN: 1424-8220

This paper is focused on the template-free synthesis of nanosized ferric oxide (nano-Fe2O3) and its application in quartz crystal microbalance (QCM) resonators to detect dimethyl methylphosphonate (DMMP), a simulant of Sarin. The X-ray diffraction (XRD) patterns confirm that the synthesized samples are made of Fe2O3 and the scanning electron microscopy (SEM) pictures show that the samples have ball-like shapes. The DMMP sensors with a sensing film of hollow ball-like and solid ball-like Fe2O3 are fabricated and their sensing characteristics are compared. The sensitivity of the hollow ball-like Fe2O3 sensor is more than 500% higher than the one of the solid ball-like Fe2O3 sensor. The hollow ball-like nano-Fe2O3 can be synthesized by a novel low temperature hydrothermal method. The sensors with the hollow ball-like Fe2O3 film perform well in a range of 1 to 6 ppm, with a sensitivity of 29 Hz/ppm at room temperature, while the appropriate recoverability and selectivity are maintained. In addition, the performance of different thicknesses of the sensing film of the hollow ball-like nano-Fe2O3 is investigated and the optimized relative film thickness of the hollow ball-like nano-Fe2O3 is found to be 20 μg/mm2.