Electrospinning high-entropy oxide nanofibers for catalytic oxidation of ethyl acetate: unraveling the synergistic role of metal–oxygen bonds
Ethyl acetate (EA) is a stable oxygenated volatile organic compound (VOC) that is challenging to fully degrade due to its strong chemical bonds. High-entropy metal oxides (HEOs) with their active lattice oxygens and diverse metal–oxygen bonds hold great potential for efficient degradation of EA. However, synthesizing HEOs without phase separation remains a significant challenge. In this study, we developed an electrospinning method to synthesize spinel-type high-entropy (CoMnNiFeZn)Ox catalysts, achieving 90% EA conversion at 266 °C with a CO2 selectivity of 100%. The catalyst demonstrated a high turnover frequency of 101.5 ± 0.8 h−1 based on the total metal content. The optimal 1 mmol-HEO catalyst demonstrated excellent stability in both five-cycle and thermal stability tests. An 18O isotope-labelled experiment confirmed that the oxidation of EA follows the Mars-van-Krevelen mechanism, with high lattice oxygen mobility significantly enhancing catalytic activity. Furthermore, in situ diffuse reflectance infrared Fourier transform spectroscopy provided insights into the roles of different metal–oxygen bonds in the catalytic mechanism. This work deepens the understanding of metal–oxygen bond interactions in the oxidation of oxygenated VOCs and offers a viable approach for synthesizing HEOs.