SnO2–Co3O4 pores composites for CO2 gas sensing at low operating temperature

SnO2 coexisted with Co3O4 was synthesized by using sol gel spin coating technique to enhance the CO2 sensing ability of SnO2–Co3O4 nanocomposites at lower operating temperature range. The structural properties of SnO2–Co3O4 were characterized by X-ray diffraction (XRD) and diffraction peaks at (110), (101), (222), (220), (422), and (511) show tetragonal rutile and cubic structures. The scanning electron micrograph revealed that spherical and rectangular morphology was formed for the DN1, DN4, DN2 samples and on increasing Co3O4 volume ratio porous morphology (like spherical) was found for sample DN3. The optical band-gap was found varying with Co3O4 contents. The SnO2–Co3O4 thin films of volume ratio 1:2 exhibited a relatively highly sensitive response to carbon dioxide gas at 30 °C. The existing studies are novel and encouraging for the understanding of SnO2:CO3O4 nanocomposites based sensor for carbon dioxide gas sensing at low operating temperatures synthesized by low cost simple spin coating techniques. [Display omitted] •SnO2–Co3O4 nanocomposite thin films were synthesized by sol-gel spin coating method fot their structural, electrical, and optical properties and CO2 gas sensing behaviour at low temperature.•The optical band gap was found 2.0, 2.1, 3.3 and 3.4 eV for thin films DN1, DN2 DN3 and DN4 samples, respectively.•The highest sensor response for samples DN1 (SnO2), DN2 (2:1), DN3 (1:2), DN4 (Co3O4) were 0.19, 0.60, 13.68 and 0.17, respectively.•The response time and recovery time of DN3 (1:2) sample were 2 s and 12 s, respectively at 30 °C.