Facile synthesis of porous ZnO nanowires consisting of ordered nanocrystallites and their enhanced gas-sensing property

Porous ZnO nanowires were obtained by a facile chemical solution route combined with subsequent calcination. Calcination of the precursors produced porous ZnO nanowires, which consist of numerous ordered nanocrystallites with high porosity resulting from the thermal decomposition of the as-prepared precursors, i.e., wire-like zinc hydroxide carbonate. Moreover, the nanostructures were characterized through X-ray diffraction, field emission scanning electron microscopy, thermogravimetric-differential thermal analysis, and Brunauer-Emmett-Teller N2 adsorption-desorption analyses, among others. The BET surface area of the porous ZnO nanowires can be calculated to be 39.1 m2 g−1. Furthermore, the gas sensing properties of the as-prepared porous ZnO nanowires were investigated using volatile organic compounds. Compared with the ZnO monocrystalline nanowires, the porous ZnO nanowires exhibited higher response with certain organic vapors, such as toluene, 2-propanol, and acetone. The responses to 100 ppm toluene, 2-propanol and acetone were 29.1, 53.7, and 57.2, respectively, at a working temperature of 300 °C. These results showed that the porous ZnO nanowires consisting of nanocrystallites are highly promising candidates for gas sensing applications.