Anchoring Sn-Containing High-Entropy Alloy PtFeCoNiCuSn on SnO₂ for Improving Acetone Detection Ability

Accurate detection of acetone (C₃H₆O) is essential for both environmental monitoring and noninvasive diabetes diagnosis. High-entropy alloys (HEAs) have been demonstrated as effective catalysts to replace noble metals for enhancing the gas-sensing performance of semiconductor metal oxides. However, HEAs tend to agglomerate at high temperatures, which severely limits their long-term stability and performance. To address this issue, a PtFeCoNiCuSn HEA was developed as a functional sensitizer for SnO₂-based C₃H₆O sensors. The existence of Sn in the HEA structure enhances the interaction of HEA with SnO₂ and prevents agglomeration under high-temperature conditions (≥300 °C), leading to improved stability and catalytic activity for C₃H₆O detection. The PtFeCoNiCuSn-SnO₂-300 sensor exhibited increased sensitivity than its Sn-free HEA counterpart, along with shorter response and recovery times (6.5 s/10.5 s) at a working temperature of 230 °C, a clear response (R_a/R_g = 4.59@2 ppm), and a low detection limit down to 4 ppb for C₃H₆O. Moreover, it demonstrated stable long-term stability, with no significant response degradation (σ = 0.056) observed over a 63-day continuous test. The enhanced performance is attributed to the synergistic effects of the HEA's multielement composition and strong metal-support interaction, which strengthens electronic interaction and the activation of surface oxygen species. This study provides a framework for enhancing the interaction between HEAs and semiconductor metal oxides to further improve the gas-sensing properties of the latter.