Enhanced ethylene glycol sensing using magnesium - modified ZnFe₂O₄ microspheres: A study on structure–performance correlation

The detection of volatile organic compounds (VOCs) such as ethylene glycol (EG) is critical due to their widespread use and associated toxicity. In this study, we synthesized magnesium-modified zinc ferrite (ZFM) nanostructures via a hydrothermal route to develop highly responsive chemiresistive gas sensors. The structural properties of the synthesized samples were optimized by varying the amount of magnesium (5 wt% and 10 wt%). Among the samples, ZFM5 exhibited excellent gas sensing performance with a maximum response of 60.56 toward 500 ppm EG with a fast response time of 4.5 s at an operating temperature of 255 °C. In addition, the ZFM10 sensing layer enabled good performance at a low temperature of 185 °C, which can highlight the tunable nature of the sensor through modifying. This performance improvement is attributed to the lattice distortion induced by magnesium and the modification of defect-related surface states, which enhance oxygen adsorption and surface redox activity. The sensors also showed excellent selectivity to EG over common VOCs such as ethanol, acetone and methanol. These findings indicate the potential of magnesium-modified ZnFe₂O₄ as a promising material for practical EG detection.