A high sensitivity gas sensor for formaldehyde based on CdO and In(2)O(3) doped nanocrystalline SnO(2)

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Formaldehyde is a common indoor air pollutant with significant health implications.
• Developing sensitive and selective gas sensors is crucial for effective formaldehyde monitoring.

Purpose of the Study:

• To investigate the gas-sensing properties of nanocrystalline tin dioxide (SnO(2)) doped with indium(III) oxide (In(2)O(3)) and cadmium oxide (CdO) for formaldehyde detection.
• To evaluate the performance of these doped SnO(2) sensors at various operating temperatures.

Main Methods:

• Fabrication of indirect-heating sensors using SnO(2)-In(2)O(3)-CdO compounds on an alumina tube with gold electrodes.
• Characterization of material phases using X-ray Diffraction (XRD) and surface morphology using Scanning Electron Microscopy (SEM).
• Gas-sensing measurements were conducted at operating temperatures ranging from 100 to 180°C.

Main Results:

• All prepared SnO(2)-In(2)O(3)-CdO sensor samples demonstrated good gas-sensing responses to formaldehyde.
• The sensors exhibited high sensitivity at a relatively low operating temperature of 133°C.
• The combination of In(2)O(3) and CdO doping enhanced the formaldehyde sensing performance of nanocrystalline SnO(2).

Conclusions:

• The In(2)O(3) and CdO doped SnO(2) sensors are effective for formaldehyde detection.
• The high sensitivity at low operating temperatures makes these sensors promising for practical formaldehyde monitoring applications.
• Further research could optimize doping concentrations and sensor architecture for improved performance.