Danial Ahmed

Acetone necessitates reliable detection for the sake of both industrial and environmental safety. Metal oxides are widely used as functional materials for the development of gas sensors because techniques like nanostructure modification, doping, and solid solution formation can enhance their sensitivity and selectivity by tuning structural and electronic properties. This study developed PrFeTiO₅ nanostructures, synthesized via the solid-state reaction for acetone sensing. The sensor demonstrated a high response to acetone at an operating temperature of 400 °C, with a low influence of humidity, displaying outstanding selectivity towards acetaldehyde, NH₃, H₂, CO, and CO₂, making it suitable across various applications.

The development of effective, cost-efficient, and printable solid-state gas sensors for the detection of volatile organic compounds is of great interest due to their wide range of applications, spanning from real-time indoor monitoring to emerging fields such as non-invasive medical diagnostics. However, gas sensors encounter difficulties in discovering materials that have both good selectivity and sensitivity for numerous volatile organic compounds in both dry and humid settings. To expand the class of sensing materials, the current study investigates the sensing performance of solid solutions based on a rare-earth metal oxide. Pr, Fe, and Ti oxide solid solutions were produced using a solid-state technique, with thermal treatments at varied temperatures to tune their structural and functional properties. The powders were used, for the first time, to produce chemoresistive sensors, which showed promising sensing capabilities vs. ethanol, acetone, and acetaldehyde. The sensors were characterized by varying the concentration of the target gases from 1 to 50 ppm in a controlled environment, with the relative humidity ranging from 2 to 40%. The findings bring a turning point, leading to fruitful paths for the development of Pr-based solid solutions-based chemoresistive gas sensors for the detection of volatile organic compounds.

The study compares three metal oxide semiconductor (MOS) sensors based on diverse WO₃ nanostructures for ammonia detection: nanoparticles, nanoflakes, and WO₃-x nanoflowers. Among them, WO₃-x nanoflowers exhibited the highest response and low-power operation (300°C). The results highlight the crucial role of nanostructure morphology and lead to further optimization to enhance response in humid environments for selective ammonia sensor.

Noxious gases such as sulfur-containing compounds can inflict several different adverse effects on human health even when present at extremely low concentrations. The accurate detection of these gases at sub-parts per million levels is imperative, particularly in fields where maintaining optimal air quality is crucial. In this study, we harnessed the capabilities of nanostructured metal-oxide semiconducting materials to detect sulfur dioxide, since they have been extensively explored starting from the last decades for their effectiveness in monitoring toxic gases. We systematically characterized the sensing performance of seven chemoresistive devices. As a result, the SnO₂:Au sensor demonstrated to be the most promising candidate for sulfur dioxide detection, owing to its highly sensitivity (0.5–10 ppm), humidity-independent behavior (30 RH% onwards), and selectivity vs. different gases at an operating temperature of 400 °C. This comprehensive investigation facilitates a detailed performance comparison to other devices explored for the SO₂ sensing, supporting advancements in gas detection technology for enhanced workplace and environmental safety.