VOC gas sensor based on hollow cubic assembled nanocrystal Zn2SnO4 for breath analysis

Hollow cubic assembled nanocrystal Zn2SnO4 was synthesized via one-step hydrothermal method for VOC gas sensing applications. The obtained Zn2SnO4 materials had a uniformly hollow cubic structure with an average size of approximately 1 mu m and a wall thickness of about 150 nm formed from nanocrystals of around 14 nm. The X-ray absorption near-edge structure results showed no structural disorder and/or lattice damage around the Zn-absorbing atoms and the Zn oxidation state of 2+ in the host lattice of the hollow cubic Zn2SnO4. The gas sensing characteristics of the prepared Zn2SnO4 material were tested to C3H6O, C2H5OH, CH3OH, NH3, H-2, and CO at 350 degrees C-450 degrees C and results showed that the sensors exhibited a good response to acetone and ethanol gases. The highest response values were 47.80 for 125 ppm of acetone and 7.52 for 10 ppm of ethanol at 450 degrees C. The Zn2SnO4 hollow cubic sensor demonstrated high sensitivity and selectivity to acetone with good stability and a detection limit of 175 ppb. The VOC sensing mechanism of the hollow cubic Zn2SnO4-based sensor was also discussed. The findings indicated that hollow cubic Zn2SnO4 is a promising material for use in excellent VOC gas sensing application towards breath analysis. (C) 2020 Elsevier B.V. All rights reserved.