Co3O4-ZnO Nanocomposites: from Plasma Synthesis to Gas Sensing Applications

Herein, we describe the design, fabrication and gas sensing tests of p-Co 3O 4/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 Co 3O 4 nanograins. Structural, morphological and compositional analyses evidenced the successful formation of pure and high-area nanocomposites with a tailored overdispersion of Co 3O 4 particles on ZnO and an intimate contact between the two oxides. Preliminary functional tests for the detection of flammable/toxic analytes (CH 3COCH 3, CH 3CH 2OH, NO 2) indicated promising sensing responses and the possibility of discriminating between reducing and oxidizing species as a function of the operating temperature.