Novel synthesis and gas sensing performances of CuO-TiO2 nanocomposites functionalized with Au nanoparticles

CuO-TiO2 nanocomposites were synthesized on Al2O3 substrates by a novel chemical vapor deposition (CVD) route, based on the sequential growth of CuO matrices (550°C) and the overdispersion of TiO2 (400°C), both performed under O2 + H2O 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-TiO2 and CuO-TiO2-Au nanosystems were tested as resistive gas sensors for toxic and flammable gases (CH3CH2OH, H2, and O3), 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-TiO2-Au nanosystems as appealing candidates in view of technological applications.