Microwave-assisted polyol synthesis of mesoporous Ta doped mixed TiO₂/SnO₂: Application for CO₂ capture

Tantalum-decorated mixed oxides (Ti_0.5Sn_0.5O₂) was successfully synthesized, using a microwave-assisted polyol process (MAP) and triethylene glycol as a solvent, in a much shorter time than conventional heating. The newly-synthesized nanocomposites materials were used to make resistive semiconductor gas sensors to detect CO₂. The powders were investigated using X-ray diffractometry, transmission electron microscopy and N₂ physisorption. The X-ray diffraction patterns of the samples confirm that TiO₂ is in the anatase phase and SnO₂ and Ti_0.5Sn_0.5O₂ are in the cassiterite phase. The TEM images showed uniform isotropic morphologies with average sizes close to 10 nm. The optimized sensor, based on TiO₂/SnO_2/Ta showed promising performances towards CO₂ capture, ensuring a high response and fast dynamics at an operating temperature of 20 °C. The CO₂ adsorption capacity was also remarkably increased from 0.58 mmol g⁻¹ for TiO₂ alone to 0.90 mmol g⁻¹ for the Ti_0.5Sn_0.5O₂. This work brings insights into a new way of limiting atmospheric pollution using mixed-oxide nanoparticles.