From Zn4(CO3)(OH)6·H2O curling nanopetals to ZnO stretching porous nanosheets: Growth mechanism and gas sensing property

Flower-like ZnO microspheres constructed by multilayered porous nanosheets were obtained through a hydrothermal preparation and a thermal decomposition. The products before and after thermal decomposition have been characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and room-temperature photoluminescence. The growth mechanism of Zn4(CO3)(OH)6·H2O curling nanopetals to ZnO stretching porous nanosheets was also proposed in this paper. The existence of a large number of oxygen vacancies improved by the adsorption of oxygen in these porous nanosheets enhanced the gas sensing property which was demonstrated by the photoluminescence spectra. The gas sensing experiments were carried out under different concentrations of ethanol and acetone at 623 K. Results showed that the porous ZnO had high response value and short response time to our testing gases. We also suggested that the sensors based on the flower-like porous ZnO microspheres are more suitable for the detection of acetone in low concentration.

► Facile preparation of ZnO microspheres was constructed by layered porous nanosheets.
► Mechanism of Zn4(CO3)(OH)6*H2O nanopetals turning into ZnO nanosheets is explained.
► Gas sensing was enhanced by large density of oxygen vacancies in the porous nanosheets.
► Porous ZnO has high response value and short response time to our testing gases.