Novel Synthesis and Gas Sensing Performances of CuO–TiO2 Nanocomposites Functionalized with Au Nanoparticles

CuO–TiO 2 nanocomposites were synthesized on Al 2 O 3 substrates by a novel chemical vapor deposition (CVD) route, based on the sequential growth of CuO matrices (550 °C) and the overdispersion of TiO 2 (400 °C), both performed under O 2 + H 2 O atmospheres. The obtained supported materials were subsequently functionalized with gold nanoparticles (NPs) by means of radio frequency (rf) sputtering. The system structure, nano-organization, and chemical composition were characterized by a multitechnique approach, using glancing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS). For the first time, both CuO–TiO 2 and CuO–TiO 2 –Au nanosystems were tested as resistive gas sensors for toxic and flammable gases (CH 3 CH 2 OH, H 2, and O 3 ), revealing attractive performances even at moderate working temperatures. Interestingly, the functional response could be appreciably enhanced upon introduction of gold NPs, highlighting the present CuO–TiO 2 –Au nanosystems as appealing candidates in view of technological applications.