Chromogenic-Functionalized Silica Nanoflower Composites for the Detection of Carbon Dioxide

Herein, we report the fabrication of chromogenic nanocomposites through the functionalization of silica nanoflowers for the detection as well as the quantification of CO2 using an optical spectroscopic technique. Silica nanoflowers have a large specific surface area and good thermal stability along with tunable surface chemistry that facilitate to produce chromogenic nanocomposites using phenolphthalein as a chromogen, for CO2 adsorption with high uptake capacity. Concentration-dependent CO2 adsorption by the chromogenic nanocomposites can be visualized through the naked eye via gradual fading of the intense pink color. We then develop a spectroscopy-based optical device (CapNanoScope) for the quantification of CO2 using the synthesized chromogenic nanocomposite, demonstrating the efficacy of the developed device for the estimation of CO2. The nanocomposites are very selective to CO2 with insignificant interference from a number of environmentally relevant gases during CO2 uptake. The present findings may open up the possibility of exploring this indigenously developed optical device for the detection and estimation of CO2.