Tin dioxide (SnO2) nanoparticles were straightforwardly synthesized using an easily scaled-up liquid route that involves the hydrothermal treatment, either under acidic or basic conditions, of a commercial tin dioxide particle suspension including potassium counter-ions. After further thermal post-treatment, the nanomaterials have been thoroughly characterized by FTIR and Raman spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen sorption porosimetry. Varying pH conditions and temperature of the thermal treatment provided cassiterite SnO2 nanoparticles with crystallite sizes ranging from 7.3 to 9.7 nm and Brunauer-Emmett-Teller surface areas ranging from 61 to 106 m2.g-1, acidic conditions favouring potassium cation removal. Exposed to reducing gas (H2, CO and volatile organic compounds such as ethanol and acetone) or oxidizing gas (NO2), layers of these SnO2 nanoparticles led to highly sensitive, reversible and reproducible responses. The sensing results were discussed in regard to crystallite size, specific area, valence band energy, Debye length and chemical composition. Results highlight the impact of the counter-ion residuals, which affect the gas-sensing performance to an extent much higher than size and surface area effects. Tin dioxide nanoparticles prepared under acidic conditions and calcined in air showed the best sensing performances due to lower potassium cation amount and higher crystallinity, despite the lower surface area.
Finely tuned SnO2 nanoparticles for efficient detection of reducing and oxidizing gases: the influence of alkali metal cation on gas sensing properties
Galstyan, Vardan;Ponzoni, Andrea;
2018-01-01
Abstract
Tin dioxide (SnO2) nanoparticles were straightforwardly synthesized using an easily scaled-up liquid route that involves the hydrothermal treatment, either under acidic or basic conditions, of a commercial tin dioxide particle suspension including potassium counter-ions. After further thermal post-treatment, the nanomaterials have been thoroughly characterized by FTIR and Raman spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen sorption porosimetry. Varying pH conditions and temperature of the thermal treatment provided cassiterite SnO2 nanoparticles with crystallite sizes ranging from 7.3 to 9.7 nm and Brunauer-Emmett-Teller surface areas ranging from 61 to 106 m2.g-1, acidic conditions favouring potassium cation removal. Exposed to reducing gas (H2, CO and volatile organic compounds such as ethanol and acetone) or oxidizing gas (NO2), layers of these SnO2 nanoparticles led to highly sensitive, reversible and reproducible responses. The sensing results were discussed in regard to crystallite size, specific area, valence band energy, Debye length and chemical composition. Results highlight the impact of the counter-ion residuals, which affect the gas-sensing performance to an extent much higher than size and surface area effects. Tin dioxide nanoparticles prepared under acidic conditions and calcined in air showed the best sensing performances due to lower potassium cation amount and higher crystallinity, despite the lower surface area.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
