Ir doping improved oxygen activation of WO3 for boosting acetone sensing performance at low working temperature

Thermally excited oxygen activation is the key to realize gas sensing by semiconductor. However, the relevant strategies and mechanisms are rarely studied. Herewith, the model material of highly oxygen catalytic active Ir doped WO3 (Ir-WO3) is prepared to elucidate the impact of enhanced oxygen activation on sensing performance. Interestingly, the 0.5 wt% Ir doped WO3 successfully reduced the working temperature of WO3 from 370 to 260 degrees C and significantly enhanced the response from 25.1 to 127.9 (at 50 ppm) for acetone. Meanwhile, the sensor also has fast response/recovery times (similar to 8.3/3.8 s), long-term stability, low detection limit (19 ppb) and high selectivity. Gas sensitive performance tests, in situ-DRIFTS and DFT calculations reveal that the Ir doping facilitates the oxygen adsorption and activation, which can significantly weaken the activation energy of acetone at low temperatures and contribute to enhance sensing performance. Our work paves a new pathway to improving metal oxide-based gas sensors at lower operating temperatures.