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 (Ra/Rg = 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.