CeO2/NiO heterostructures for extremly-selective acetone detection: The critical role of the Ce3+/Ce4+ ratio in NiO nanodomes

초록

Exhaled breath analysis has emerged as a promising and non-invasive approach for diagnosing disease by detecting specific biomarkers. Acetone in exhaled breath can be used as a biomarker in diabetic patients, promoting the development of highly sensitive and selective acetone gas sensors. In this study, CeO2-decorated NiO nanodomes (NDs) were developed to enhance the response and selectivity for acetone detection. The optimal response was achieved using the NDs decorated with 5 nm thick CeO2, at 400 °C, affording about a 15.5-fold increase in the selective acetone response (Rgas/Rair − 1 = 25.4, 50 ppm). The enhanced gas response led to a ppb-level theoretical detection limit for the CeO2-decorated NiO NDs, even under humid conditions. This improvement is attributed to the formation of a p–n junction, as well as the increased contents of oxygen defects in sensing layers, driven by the higher Ce3+/Ce4+ ratio. These oxygen defects facilitate greater adsorption of oxygen ions on the CeO2 and NiO surface, thereby enhancing the gas sensing performance. These results demonstrate the potential of CeO2-decorated NiO NDs for highly selective acetone detection, paving the way for non-invasive breath-based diagnostics. © 2025 Elsevier B.V.

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