Sniffing Out Glutaraldehyde Disinfectants with Mesoporous Lanthanum-Doped Tin Dioxide Spheres

The electronic nose, an innovative system designed to emulate the olfactory capabilities of biological organisms, shows promising utility across various sectors, including environmental monitoring, disease diagnosis, public safety, and food engineering. The effectiveness of electronic noses largely depends on the sensitivity and selectivity of their gas sensors, which currently face challenges in these areas.

To address these limitations, a chemiresistive gas sensor was fabricated with a gas-sensitive material comprising mesoporous lanthanum-doped tin dioxide spheres, utilizing a self-templating approach coupled with direct thermal decomposition. The spheres had a uniform size (~77 nm in diameter), large pore size (~5.7 nm), and high specific surface area (52-59 m²/g). Based on these characteristics, the chemiresistive gas sensor exhibited exceptional performance in the detection of glutaraldehyde, with a high response value (13.5@10 ppm), rapid response time (28 s), remarkable stability, and a low detection limit (0.16 ppm). The observed sensitivity was threefold higher than that of sensors made from undoped mesoporous tin dioxide spheres. This enhancement could be attributed to lanthanum's ability to improve oxygen diffusion, adsorption, and ionization on the material's surface, thereby increasing the electron depletion layer's thickness and detection sensitivity. Density Functional Theory (DFT) calculations further confirmed that lanthanum doping enhanced the adsorption energy towards glutaraldehyde molecules, facilitating electron transfer and improving sensor performance.

By doping gas-sensitive materials with rare earth elements, it is possible to modulate the interaction between gas molecules and the material's surface interface, significantly improving gas sensing performance. This study not only advances the development of high-performance sensors for glutaraldehyde disinfectants but also lays the groundwork for designing advanced gas sensors and enhancing the capabilities of electronic noses.

This work has been published in ACS Sensors (https://pubs.acs.org/doi/10.1021/acssensors.3c00953) and has been selected as the Front Cover.