Lanthanum Phosphate-Incorporated Organosilane Nanocomposites for Gas-Phase CO₂ Detection

A facile, sol–gel method to produce fluorescent, organically modified silica (ORMOSIL)–lanthanum phosphate (LaPO4) hybrid nanocomposites suitable for gas-phase CO2 detection through a fluorescence-quenching mechanism is reported in the present work. ORMOSIL–LaPO4 hybrid nanocomposites are prepared from a hybrid nanocomposite composition derived from trifunctional silanes such as methyltrimethoxysilane (MTMS), glycidoxypropyltrimethoxysilane (GPTMS), and from LaPO4 nanorods, which act as fluorescent additives in the organically modified silane (ORMOSIL) matrix. Hybrid nanocomposite compositions containing MTMS and GPTMS were prepared in which the amount of LaPO4 was varied. The wet alcogels thus obtained were dried under ambient conditions for 7 days, resulting in nanocomposite powders, and were calcined at 400 °C. The prepared nanocomposites were further characterized for their structural and functional features. The functional ORMOSIL matrix together with a luminescent additive like LaPO4 makes the prepared ORMOSIL–LaPO4 nanocomposite highly photoluminescent. The hybrid nanocomposite with nanoporous features exhibited a room-temperature CO2 adsorption property and the photoluminescence intensity was found to quench with respect to CO2 adsorption, which demonstrates the potential of the material to be used as a viable CO2 sensor.