Effect of crystallinity of TiO₂ in Au@TiO₂ core-shell nanoparticles on CO sensing properties

Au@TiO₂ core-shell nanoparticles (NPs) were synthesized by microwave-assisted hydrothermal method. Au NPs with 40±5 nm size were synthesized by colloidal method. TiO₂ shell layer with 60±10 nm shell thickness was deposited on Au NPs by microwave-assisted hydrothermal method. The average particle size of TiO₂ NPs was ∼13 nm and particle size increased with increasing reaction temperature without considerable change in shell thickness. The crystallite size increased with increasing synthesis temperature as well as time. The response of Au@TiO₂ core-shell NPs was increased with increasing synthesis temperature as well as time due to increase in crystallinity of TiO₂.