Heterostructured NixFe3-xO4 composites for sub-ppm acetone detection

Acetone is a crucial biomarker of diabetes diagnosis by breath analysis. However, the fabrication of metal oxide semiconductor-based sensors with the desired gas-sensing abilities for sub-ppm acetone detection remains a significant challenge. In this study, heterostructured Ni_xFe_3-xO₄ composites with varying Ni concentrations were effectively developed using a simple one-step solvothermal process followed by post-calcination treatment. The sensor based on Ni_xFe_3-xO₄ composites exhibited excellent gas sensing performance toward 50 ppm acetone due to the formation of unique microstructures and numerous active sites. Notably, the optimum Ni_0.8Fe_2.2O₄ sensor demonstrated remarkable sensitivity even at sub-ppm levels, showing good monotonically increasing response (R² = 0.994) within the concentration range of 0.1–5.0 ppm acetone. Moreover, distinct signal responses between exhaled breath samples from a healthy individual and a simulated diabetic patient were observed in the Ni_0.8Fe_2.2O₄ sensor, implying that the Ni_xFe_3-xO₄ composites provided an alternative novel strategy for the effective detection of acetone in actual breath analysis of diabetes diagnosis.