Synergistic dual-site enhancement in Pd/In2O3: Toward real-time detection for early electrical fire warning

For the early warning of electrical fire, it is of great significance to selectively and timely detect 2-ethylhexanol (2-EH), which is a key gaseous product released from the overheated PVC covered on cables. However, the detection of 2-EH is always hindered due to the weak adsorption and activation ability of the sensing materials. Herein, we constructed dual sites contained Pd-In 2 O 3 sensor for the detection of trace 2-ethylhexanol at ppb level. In this structure, hydroxyl oxygen in 2-EH forms significant bond with In atoms, while alkyl hydrogen generates strong interaction with Pd cluster. As a result, the 0.3 Pd-In 2 O 3 sensor exhibits high response (S = 42 at 11 ppm), low detection limit (0.11 ppm) and short response time (2 s). Band structure analysis reveals that the formation of Schottky junction and spontaneous electron transfer between In 2 O 3 and Pd, leading to the improved gas-sensing performance. This work not only offers new insights into the sensing mechanism by DFT calculations but also paves the way for designing high-performance gas-sensitive materials targeted at complex organic molecules.