Facile fabrication of chromium oxide micro/nanospheres and enhanced ethanol gas sensing performances

Chromium oxide (Cr2O3) micro/nanospheres are skillfully designed and successfully synthesized by a facile route without any templates or surfactants. Morphology and structure characterizations reveal that Cr2O3 micro/nanospheres are assembled by irregular nanoparticles as primary building blocks and present loose hierarchical architecture. The Cr2O3 micro/nanospheres sensors exhibit rapid response and recovery kinetics (5 s and 6 s), good selectivity and remarkable repeatability to ethanol gas at 220 °C, and the sensitivity to 100 ppm ethanol is about 4 times higher than that of the collapsed Cr2O3 micro/nanospheres based sensors. The enhanced gas sensing performances are predominantly attributed to the synergistic effect of the unique sphere-like architecture and highly loose structure, thus providing beneficial conditions to greatly improve gas diffusion, adsorption and surface reaction.