Platinum dioxide activated porous SnO2 microspheres for the detection of trace formaldehyde at low operating temperature

•The PtO2/SnO2 composite sensor can detect trace amount of gaseous formaldehyde.•The PtO2/SnO2 composite give good selectivity towards formaldehyde.•The optimal working temperature is around 100 °C.

Great efforts have been devoted on the detection of the volatile organic compounds indoor for human health. The detection of formaldehyde is one of the most important and popular issues for the wide usage of formaldehyde and its toxic. However, it is a challenge to monitor trace gaseous formaldehyde at lower working temperature. Herein, we present a sensor with a significantly improved sensing response and dramatically decreased operating temperature based on porous PtO2/SnO2 microspheres. And the PtO2/SnO2-5 mol% composite shows the most outstanding sensing performance among all products. What's more, the above sensor can detect gaseous formaldehyde in the ppb level (100 ppb) at low operating temperature (100 °C). The excellent sensing performance should be attributed to the high catalytic activity of PtO2 nanoparticles decorated on the surface of SnO2 microspheres and the porosity of the composite.