Humidity‐Resistant CeO 2 /In 2 O 3 Nanocomposite‐Based Chemiresistor for Selective Detection of Formaldehyde

Abstract Formaldehyde is a frequent indoor pollutant that poses a risk to human and environmental health and is suspected to be a carcinogen. However, achieving high sensitivity and selectivity for real‐time applications remains challenging. In this study, a room‐temperature operated formaldehyde chemiresistor is developed by cerium dioxide/indium oxide (CeO 2 /In 2 O 3 ) nanocomposite for exclusive detection. The nanocomposite is synthesized using hydrothermal, forming CeO 2 nanospheres grown on In 2 O 3 nanocubes. This unique structure enhances the sensing capabilities of CeO 2 /In 2 O 3 , allowing it to detect formaldehyde in the 1–50 ppm range, and a 0.157 ppm detection limit is earned. The sensor exhibits an impressive response of 175.05 at 50 ppm at room temperature and shows responsiveness to various other substances, for instance, methanol, ethanol, aniline, benzene, toluene, acetone, and ammonia. Additionally, the CeO 2 /In 2 O 3 sensor demonstrated moderate to high selectivity, sensitivity, stability, speedy response/recovery times, and resilience to humidity. This work presents a promising strategy for the detection of formaldehyde.