Bimetallic co-growth of In2O3/Co3O4 porous nanorods for rapid detection of acetone gas

Acetone, a critical biomarker in exhaled breath for the diagnosis of diabetes, necessitates the development of high-performance gas sensors for real-time monitoring. In this work, bimetallic In₂O₃/Co₃O₄ porous nanorods with tunable In/Co molar ratios were synthesized via a hydrothermal approach. The optimized sensor 3-ICO (In:Co = 3:10, molar ratio), exhibited remarkable acetone-sensing performance with a high response of 125.6–10 ppm acetone at 250 °C, ultrafast response/recovery times (45 s/19 s), outstanding selectivity, and long-term stability. The integration of materials characterization with density functional theory (DFT) simulations demonstrated that the p-n heterojunction formed between Co₃O₄ and In₂O₃ facilitates interfacial charge transfer, enhancing both the oxygen vacancy concentration and specific surface area. These synergistic effects significantly improve acetone adsorption energy and electron transport efficiency. This work highlights the pivotal role of heterojunction engineering in optimizing the detection performance of metal-oxide semiconductors for low-concentration volatile organic compounds (VOCs), offering promising applications in non-invasive diabetes diagnosis.