A highly sensitive and selective formaldehyde gas sensor using a molecular imprinting technique based on Ag–LaFeO3

Abstract

A novel formaldehyde gas sensor has been developed for the first time using a molecular imprinting technique (MIT) in semiconductor oxides to recognize small organic molecules. For specific recognition, the as-prepared molecularly imprinted nanoparticles exhibit good selectivity for formaldehyde. The molecularly imprinted nanoparticles were mixed with Ag–LaFeO₃ to form a compound. The compound with small dimensions and good dispersity possesses an extremely high surface-to-volume ratio. Therefore the compound exhibits even better formaldehyde-sensing properties. At 40 °C, the response to 0.5 ppm formaldehyde based on the compound is 24.5, and is lower than 3.0 to the other test gases. The response time and recovery time are 67 s and 104 s, respectively.