WS2 quantum dots modified In2O3 hollow hexagonal prisms for conductometric NO2 sensing at room-temperature

The fabrication and investigations of a novel NO2 gas sensor based on a 1T and 2H mixed phase WS2 quantum dots (QDs) modified MOF-derived hollow In2O3 (WS2 QDs@In2O3) heterostructure were documented. The proposed gas sensor based on WS2 QDs@In2O3 hollow hexagonal prisms was simple, sensitive, cost-effective and worked at room temperature (25 +/- 2 degrees C). The response value of 3 wt% WS2 QDs@In2O3 (W3In) towards 100 ppm NO2 could reach to 2034, which was an ultra-high value and almost 7.7 times higher than that of pure In2O3. Besides, our sensor showed excellent selectivity to NO2 and could detect concentration down to 100 ppb. The enhanced NO2 sensing performance was observed due to the synergistic effect between WS2 and In2O3. Furthermore, the compensation response values to NO2 based on the response to water vapor under different humidity of W3In were calculated and their fluctuations are within 7.8 % compared with the response under 25 % RH, which could provide a new strategy for accurately detecting NO2.