Evaluation of barium–strontium nanoferrite-based sensors for VOC detection: the case of ethanol and acetone

Abstract

Over the past few decades, traditional approaches to detecting volatile organic compounds (VOCs) have been transformed by the integration of data intelligence, allowing valuable insights into sensor behavior when exposed to different gases. In gas sensing, VOCs such as acetone and ethanol are commonly used to evaluate sensors due to their closely related chemical properties, which makes distinguishing between them particularly challenging. In this study, we evaluated the detection of ethanol and acetone gases using spinel nanoferrites Ba_0.5−xSr_xFe_2.5O₄ (x = 0.00, 0.25 and 0.50). The materials exhibit structural features that favor gas adsorption and surface reactivity. Electrical measurements confirmed their n-type semiconductor behavior, and sensing tests performed over a wide range of gas concentrations (500 ppb to 100 ppm) demonstrated high sensitivity, even at very low concentrations. All three compositions showed exceptionally low detection limits, which represents a key advantage for the rapid and efficient detection of acetone and ethanol. Furthermore, the sensors displayed high sensitivity, exceeding values previously reported in the literature, along with very short response and recovery times, highlighting their strong potential for real-time applications. Our results indicate that Ba²/Sr² substitution does not significantly affect VOC sensitivity, but emphasize the crucial role of the nanostructured architecture of the ferrites in enhancing gas sensing performance.