A ZIF-8-based platform for the rapid and highly sensitive detection of indoor formaldehyde

Abstract

A rapid and highly sensitive sensor that can quantitatively detect indoor gaseous formaldehyde in 5 min based on Zeolitic Imidazolate Framework-8 (ZIF-8) is presented. ZIF-8 was synthesized from nontoxic zinc ions and 2-methylimidazole in aqueous solution at room temperature. The morphology, microstructure, stability and photoluminescence properties of the material were characterized by scanning electron microscopy, nitrogen adsorption–desorption, X-ray diffraction, thermogravimetric analysis and fluorometric analysis techniques. The results showed that the obtained material had a uniform particle size, possessed excellent thermal and structural stability and had good luminescent properties. Under the optimized conditions, the photoluminescent intensity of the guest-free phase ZIF-8 was linear with formaldehyde concentration in two intervals, 0–0.5 ppm and 0.5–20 ppm, with corresponding correlative coefficients of 0.9991 and 0.9819, respectively. The limit of detection for gaseous formaldehyde was calculated to be 0.057 ppm (3δ per slope criterion). Moreover, other indoor pollutants, such as benzene, toluene, methanol and ethanol, which can be emitted from indoor decorative materials, showed little interference with the photoluminescence intensity of this platform during the determination process. The material exhibits great potential in the field of rapid, convenient and highly sensitive detection of indoor gaseous formaldehyde.