摘要
Spinel ferrite (MFe 2 O 4 ) has emerged as an ideal candidate material for non-invasive breath analysis acetone sensors in diabetes diagnostics due to its outstanding chemical stability and exceptional surface redox activity. However, existing MFe 2 O 4 -based gas sensors remain constrained by critical limitations, including high detection limits and low sensitivity to sub-ppm levels of acetone, which hinder their practical application in diabetes diagnosis. This study developed a simple and efficient strategy for successfully preparing ZnO/ZnFe 2 O 4 heterojunction composites by adjusting the pH of the solution. Specifically, leveraging the drastic solubility difference between Zn 2+ and Fe 3+ ions, we achieved controlled formation of ZnO/ZnFe 2 O 4 heterophases within a specific pH range (5.02–5.35). These structural features facilitate the adsorption of acetone molecules and boost the efficiency of charge transfer, thereby endowing the composites with superior acetone-sensing performance at the sub-ppm level. Notably, the as-synthesized ZnO/ZnFe 2 O 4 (pH = 5.02) heterogeneous composites exhibited exceptional gas-sensing performance toward 1.0 ppm acetone, including a low detection limit of 0.40 ppb, a high response (13.76), a fast response time of 6 s, excellent selectivity, long-term operational stability, and robust humidity tolerance. More importantly, the ZnO/ZnFe 2 O 4 sensor could successfully distinguish exhaled breath samples from healthy individuals and simulated diabetic patients, thus highlighting its potential for clinical breath analysis. The results demonstrate that the preparation of ZnO/ZnFe 2 O 4 heterojunction composites with tunable surface states and surface barriers through rational synthetic strategies provides a new paradigm for designing high-performance spinel ferrite-based composites, thereby advancing the development of non-invasive diabetes diagnostic tools.
危险品化学品经营许可证（带存储）