Co3O4/ZnO Nanocomposites: From Plasma Synthesis to Gas Sensing Applications

Herein, we describe the design, fabrication and gas sensing tests of p-Co3O4/n-ZnO nanocomposites. Specifically, arrays of <001> oriented ZnO nanoparticles were grown on alumina substrates by plasma enhanced−chemical vapor deposition (PECVD) and used as templates for the subsequent PECVD of Co3O4 nanograins. Structural, morphological and compositional analyses evidenced the successful formation of pure and high-area nanocomposites with a tailored overdispersion of Co3O4 particles on ZnO and an intimate contact between the two oxides. Preliminary functional tests for the detection of flammable/toxic analytes (CH3COCH3, CH3CH2OH, NO2) indicated promising sensing responses and the possibility of discriminating between reducing and oxidizing species as a function of the operating temperature.