Improving the gas-sensing performance of SnO2 porous nanosolid sensors by surface modification

The gas-sensing performance of SnO2 porous nanosolid (PNS) sensors was modulated via a surface modification strategy by calcining the sensors in different atmospheres. It was found that the response of SnO2 PNS sensors greatly improved (the maximum sensor response to 1000 ppm CO is 45.6) after being calcined in atmospheric-pressure nitrogen. However, the sensor response firstly decreased to a large extent after being calcined in 0.1-10 MPa oxygen, reaching a minimum value of ∼5.1 at 4.0 MPa and followed by a slight increase with the oxygen pressure further increasing. Contrarily, the SnO2 PNS sensors exhibited monotonically deteriorating gas-sensing performance after being calcined in nitrogen of ever-increasing pressure. The mechanism related to the above phenomena was preliminarily explained by using the corresponding Hall effect and XPS measurement results.