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

[Display omitted] •SnO2 is obtained by hydrothermal method, at different synthesis temperatures.•SnO2 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 %.•CO2 concentration varies between 400 and 5000 ppm CO2. This letter highlights the role of synthesis temperature over the morpho-structural properties of SnO2. 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 SnO2 in detecting CO2. The in-field conditions are ensured by dynamic synthetic air flow with variable relative humidity, a wide range of CO2 concentrations and potential interfering gases at their specific detection limits.