SnO2 QDs sensitized ZnFe2O4 spheres with enhanced acetone sensing performance.

Herein, SnO2 QDs (<10 nm) with small size instead of conventional nanoparticles was employed to modify ZnFe2O4to synthesize porous and heterogeneous SnO2/ZnFe2O4(ZFSQ) composites for gas sensing. By an immersion process combined with calcination treatment, the resultant porous ZFSQ composites with different contents of SnO2 QDs were obtained and their sensing properties were investigated. Compared with that of bare ZnFe2O4 and SnO2 QDs, porous ZFSQ composites based sensors showed much improved sensor response to acetone. For contrast, the sensor performance of ZFSQ composites was also compared with that of ZnFe2O4 sphere modified with SnO2 nanoparticles. The porous ZFSQ composite with 5 wt% SnO2 QDs (ZFSQ-5) showed better acetone sensing response than that of other ZFSQ composites, and it exhibited a high response value of 110 to 100 ppm of acetone and a low detection limit of 0.3 ppm at 240℃ . In addition to the rich heterojunctions and porous structure, SnO2 QDs with large surface area and quantum effect was another indispensable reason for the improved sensor performance. Finally, the ZFSQ-5 composite sensor was attempted to be applied for acetone sensing in exhaled breath, suggesting its great potential in monitoring of acetone.&#xD.