Effects of ZnO crystal facet on the ethanol detection by the Au/ZnO sensors

In this paper, Au nanoparticles loaded ZnO nanocones with the dominant {10 (1) over bar1} facet, nanoflakes with the dominant {0001} facet, and nanorods with the dominant {10 (1) over bar0} facet were synthesized and the crystal facet effects of the ZnO on the ethanol-sensing property of the Au/ZnO sensors were investigated. The size of gold nanoparticles and the ethanol-sensing response strongly depended on the facet structures of the ZnO supports. The high surface energy of {10 (1) over bar1} facet led to the strong interaction between the Au nanoparticles and the ZnO nanocones, which was beneficial to the stability of Au nanoparticles and the increase of the catalytic activity of the Au/ZnO nanocones. Temperature-programmed surface reaction results indicated that the high activity of the Au/ZnO nanocones accelerated the ethanol-sensing reaction. The acceleration resulted in the remarkable change of depletion layer and high ethanol-sensing response.