ZnO nanocrystals with a high percentage of exposed {4 (2)over-bar(2)over-bar (3)over-bar} reactive facets for enhanced gas sensing performance

Zinc oxide single crystals with a high percentage of exposed {4 (2) over bar(2) over bar(3) over bar reactive facet were prepared by a facile hydrothermal route. X-ray diffraction, field emission scanning electron microscopy, and high resolution transmission microscopy confirmed the faceted single crystal structure. Through the density functional theory (DFT) calculations, it is validated that the [4 (2) over bar (2) over bar (3) over bar surface of ZnO crystals has high surface energy. When used as a sensing material in gas sensors, ZnO crystals with dominating exposed {4 (2) over bar(2) over bar(3) over bar} planes exhibited a superior sensitivity toward toxic and flammable gases. (C) 2013 Elsevier B.V. All rights reserved.