(CoCrFeMnNi)3O4 high-entropy oxide acetone sensor: Ultra-fast response and highly sensitive detection

• One-step synthesis of high-entropy oxide (CoCrFeMnNi) 3 O 4 by coprecipitation method. • Achieved a high selectivity response of 1.97 to 200 ppm acetone. • The first breakthrough of sub-second response in high-entropy oxide sensors(8 s). • The multi-cation synergy enhancement mechanism. This work, cubic spinel-structured (CoCrFeMnNi) 3 O 4 high-entropy oxide (HEO) was synthesized through the co-precipitation method. The material’s microstructure and composition were analyzed using SEM, TEM, XRD, and XPS techniques, while its gas sensitivity performance was evaluated. The results indicated that the material exhibited outstanding selectivity (1.97) to 200 ppm acetone at 260 °C, with response/recovery times of 8 s and 44 s respectively. It demonstrated excellent repeatability and long-term reliability. The excellent gas sensitivity results from high entropy effect: multiple cations enhance active sites and oxygen vacancies for better acetone adsorption and oxidation; the entropy-stabilized spinel phase prevents phase separation, keeping performance fluctuations below 3 % over four weeks at 260 °C, indicating remarkable stability.