Ag decorated SnO2 nanoparticles to enhance formaldehyde sensing properties

Silver, as a cheaper and good conductivity noble metal, has successfully been decorated on SnO2 nanoparticles to structure the Ag-SnO2 composites by a facile hydrothermal and in situ reduction method. The difference of structure and properties between SnO2 and composite was characterized by XRD, FESEM, elemental mapping, UV-vis spectroscopy, BET and XPS surface analysis. The sensing performance of SnO2 and composite to formaldehyde were also examined. The composite of 3.7 wt% Ag decorated SnO2 not only exhibits the high response to 10 ppm of formaldehyde but also has better stability and selectivity at an operating temperature of 125 degrees C. Moreover, the detection limit of the composite was determined to be 0.53 ppm, which is lower than that of pure SnO2 nanoparticles. The response mechanism of the composite to formaldehyde was also discussed in detail, which is attributed to the catalytic effect and the spillover effect of Ag nanoparticles.