SnO2 Nanoparticles Derived from Metal-Organic Precursors as an Acetaldehyde Gas Sensor with ppb-Level Detection Limit

Acetaldehyde gas sensors are highly important for protectinghumanhealth. However, it is challenging to achieve rapid acetaldehyde detectionat low concentrations and low operating temperatures. In this work,SnO2 nanoparticles were synthesized by the calcinationof amorphous metal-organic precursors prepared by hydrothermaltreatment. The effects of different molar ratios of pure terephthalicacid (PTA)/SnCl2 & BULL;2H(2)O on the microstructuresand gas-sensing properties of the synthesized particles were thoroughlyinvestigated. The results showed that the obtained SnO2 particles were crystalline with sizes between 8 and 20 nm. Althoughthe specific surface area of the SnO2 particles increasedslightly from 57.65 to 65.19 m(2)/g as the molar ratio ofPTA/SnCl2 & BULL;2H(2)O increased, prominent chemisorbedoxygen species and oxygen vacancies were only present in the SnO2-3 sample with a molar ratio of 1:1. Meanwhile, the sensorfabricated with SnO2-3 exhibited a high response value(10.69), an extremely fast response (3 s), and a good recovery (4s) time when exposed to 40 ppm of acetaldehyde at 100 & DEG;C. Moreinterestingly, it also exhibited a low limit of detection of 50 ppbfor acetaldehyde gas, as well as good selectivity and long-term stability.A promising sensor for low-temperature and low-concentration acetaldehydegas detection was developed, and the mechanism behind its sensingperformance was thoroughly explored.