SnO2 QDs loaded α-Fe2O3 hollow cubes for H2S room temperature detection and insights into their gas sensing mechanism

Since H2S gas is flammable and explosive, it has significance to realize H2S detection at room temperature. In this work, different amounts of SnO2 quantum dots (QDs) were loaded on Prussian blue derived α-Fe2O3 hollow cubes, which exhibits an uneven porous granular surface structure evidenced by characterization of TEM and SEM. Aiming H2S as target gas, the α-Fe2O3/SnO2 composites demonstrate greatly improved gas sensing performance at room temperature. Specifically, the response value of S1 to S4 (different SnO2 QDs loads) to 5 ppm H2S at room temperature are 4.97, 5.76, 8.21 and 6.69 respectively, which has a trend from rise to decline as the SnO2 QDs increases. Optimum sensitivity is achieved by 10 wt% SnO2 loading. Finally, characterizations such as BET, XPS and DRIFTS et al. reveal that the effective electron transfer from SnO2 to α-Fe2O3 via energy band match promotes the chemisorption oxygen and density and mobility of charge carriers, which is beneficial to H2S gas sensing.