Synthesis, characterization and gas sensing properties of Ag@α-Fe2O3 core–shell nanocomposites

Ag@alpha-Fe2O3 nanocomposite having a core-shell structure was synthesized by a two-step reduction-sol gel approach, including Ag nanoparticles synthesis by sodium borohydride as the reducing agent in a first step and the subsequent mixing with a Fe+3 sol for alpha-Fe2O3 coating. The synthesized Ag@alpha-Fe2O3 nanocomposite has been characterized by various techniques, such as SEM, TEM and UV-Vis spectroscopy. The electrical and gas sensing properties of the synthesized composite towards low concentrations of ethanol have been evaluated. The Ag@alpha-Fe2O3 nanocomposite showed better sensing characteristics than the pure alpha-Fe2O3. The peculiar hierarchical nano-architecture and the chemical and electronic sensitization effect of Ag nanoparticles in Ag@alpha-Fe2O3 sensors were postulated to play a key role in modulating gas-sensing properties in comparison to pristine alpha-Fe2O3 sensors.