The impact of the synthesis temperature on SnO2 morphology and sensitivity to CO2 under in-field conditions

• SnO 2 is obtained by hydrothermal method, at different synthesis temperatures. • SnO 2 crystalline nanoparticles are faceted, with regular morphologies. • Main crystallographic planes (001), (101), (110) contain oxygen positions. • The sensing properties are evaluated under in-field conditions, RH=0-50% • CO 2 concentration varies between 400 and 5000 ppm CO 2. This letter highlights the role of synthesis temperature over the morpho-structural properties of SnO 2 . Specific crystalline nanoparticles with quasi-tetragonal and quasi-hexagonal morphologies are faceted, suggesting a high reactivity to atmospheric oxygen. This is a premise for the sensing ability of SnO 2 in detecting CO 2 . The in-field conditions are ensured by dynamic synthetic air flow with variable relative humidity, a wide range of CO 2 concentrations and potential interfering gases at their specific detection limits.