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 x Fe 3-x O 4 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 x Fe 3-x O 4 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 0.8 Fe 2.2 O 4 sensor demonstrated remarkable sensitivity even at sub-ppm levels, showing good monotonically increasing response (R 2 = 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 0.8 Fe 2.2 O 4 sensor, implying that the Ni x Fe 3-x O 4 composites provided an alternative novel strategy for the effective detection of acetone in actual breath analysis of diabetes diagnosis.