Low-Temperature Ethylene Glycol Sensing by Zn-Modified SnO2 Nanosheet Assemblies: Experimental Characterization and DFT Analysis

Pure and nominally Zn-modified SnO2 nanostructures were synthesized by a one-step hydrothermal route and evaluated as chemiresistive sensors for ethylene glycol (EG). Zn addition was associated with a change from relatively thick nanoplates to finer nanosheet-like units, while X-ray diffraction retained the rutile SnO2 pattern. At 100 °C, the Zn-containing sensor gave responses of 81.19 toward 50 ppm EG and 208.07 toward 130 ppm EG; the latter was approximately 12 times the response of pure SnO2 within the same concentration series. At 50 ppm, its response and recovery times were 153 and 42 s, respectively. The EG response remained measurable from 20 to 80% relative humidity. Density-of-states calculations for pristine SnO2(110) and an idealized Zn-substituted slab showed a redistribution of orbital-projected states, offering a qualitative electronic perspective on the sensing behavior.