Dual-sensitized hollow SnO₂ nanospheres with rGO and Pd for highly sensitive detection of acetone in exhaled breath

Detecting acetone in human breath is crucial for the early diagnosis of metabolic disorders such as diabetes. Metal oxide semiconductor (MOS) based acetone breath sensors have received considerable attention due to their compactness and noninvasive nature. However, their limited sensitivity and interference from humidity present challenges in selectively detecting acetone. Herein, we propose sensors based on tin oxide hollow spheres dual-sensitized with reduced graphene oxide and ultrafine palladium nanoparticles (rGO-Sn-HS-Pd) for enhanced and selective detection of acetone. The Sn-HS are synthesized using a spray pyrolysis technique, followed by a hydrothermal process to achieve the rGO-Pd-NPs dual-sensitized SnO₂ hollow spheres. The rGO-Sn-HS-Pd sensor demonstrate high sensitivity to acetone, exceptional selectivity, and fast response/ recovery. Furthermore, by utilizing a linear fitting approach on the experimental response data for acetone concentrations, it is estimated that the rGO₂-Sn-HS-Pd₂ sensor can detect acetone as low as 220 ppb. The optimized rGO₂-Sn-HS-Pd₂ sensor demonstrates performance that is 7.35, 5.38, 3.87, 4.57, 1.27, and 1.15 times higher compared to the bare Sn-HS, rGO₁-Sn-HS, rGO₂-Sn-HS, rGO₃-Sn-HS, rGO₂-Sn-HS-Pd₁, and rGO₂-Sn-HS-Pd₃ sensors. Sensor arrays incorporating rGO₂-Sn-HS-Pd₂ can distinguish breath patterns between healthy and simulated diabetic breath through principal component analysis, presenting a promising avenue for noninvasive diabetes screening and monitoring.