ppb-Level Triethylamine Gas Sensor Based on Ag-Decorated CuO Nanosheets with Lowered Operating Temperature

The development of high-performance triethylamine (TEA) gas sensors operating at reduced temperatures remains a challenge for practical applications. Here, we address this by decorating CuO nanosheets with Ag nanoparticles at controlled molar ratios (0.1:1, 0.2:1, and 0.3:1). Compared with pure CuO, the optimal Ag/CuO sensor (0.2:1) achieves a 13.3-fold higher response to 100 ppm TEA and lowers the operating temperature by 60 °C, while also enabling ppb-level detection. Experimental and density functional theory (DFT)-based mechanistic studies reveal that Ag nanoparticles act as catalytic centers that not only promote surface reactions but also enhance electron transfer, collectively accounting for the observed improvement. This work provides a simple and effective design strategy for practical gas sensors via rational noble metal loading.