Microwave assisted hydrothermal synthesis of well-dispersed and thermally stable Ag@SnO₂ core–shell nanocomposites for propane sensing applications

A simple microwave assisted hydrothermal precipitation (M–H) technique for the synthesis of Ag@SnO₂ core–shell structure nanoparticles (NPs) is reported. Ag NPs were synthesized via chemical reduction of metal salt followed by M–H deposition of tin dioxide shell for fabrication of monodispersed core–shell particles. The phase and morphology has been investigated by X-ray diffraction technique (XRD) and transmission electron microscopy (TEM) respectively. Ag@SnO₂ core–shell nanocomposites have shown distinct surface Plasmon spectrum in the range of 407–440 nm. The core–shell morphology is confirmed from the TEM images. XRD patterns have suggested the formation of silver and tin dioxide in the face-centered cubic and Cassiterite form respectively. Our investigations suggested that the formation of core–shell structure results in the enhanced thermal stability of the system. Synthesized material is used for the detection of propane gas. To understand the multi gas sensing ability and selectivity for detection of propane gas by Ag@SnO₂ core–shell materials based devices, Sinha–Tripathy soft-sensor model has been proposed.