Low cost ternary metal oxide based nanocomposites as a room temperature formaldehyde sensor

To protect human health from hazardous gases, it is necessary to rapid detection of toxic gases utilizing gas sensors. Though there are various gas sensors, despite that, they endure inaccuracy in selectivity and sensitivity in the real-time monitoring of the low concentration of gases. In this context, the practical design for developing a cost-effective formaldehyde (HCHO) sensor using a hetero-type ternary nanocomposite ZnO/CdO/CuO (ZCCO) metal oxide (MOX) materials with porous structure is an ideal choice. In this study, ZCCO heterostructures demonstrated rapid selectivity towards HCHO compared with other volatile organic compounds and exhibited excellent long-term stability for up to 80 d. The sensor capability has been further improved with the heterostructures' porous morphology, greater specific surface area, huge reaction sites, and electron sensitization effects of highly dispersed nanocomposite material. This work reports the Lowest Detection Limit (LDL) towards HCHO at room temperature as 250 ppb. These heterostructures enable the charge transport mechanism between the interparticle ZnO/CdO (n-n junctions) and the ZnO/CuO (n-p junctions) that can simultaneously enhance the sensitivity of the gas molecule's reactions.