Sn doped ZnO layered porous nanocrystals with hierarchical structures and modified surfaces for gas sensors

In this paper, a simple solvothermal method is developed for the synthesis of Sn doped ZnO layered porous nanocrystal (Sn-ZLPC). Scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy are used to characterize the detailed structures and surface/near-surface chemical composition of the as-prepared products. Sn doping is found to be the key factor controlling the layered porous structure. The possible growth mechanism of Sn-ZLPC is also discussed. As the stability of target gas increases, the optimal operating temperature shifts from 300 degrees C to 500 degrees C and the highest response shifts to the sample with high atomic ratio of Sn. The later shift is attributed to the alternate key influence of the activation energy and adsorption/desorption of oxygen ions. 5.0 at% Sn-ZLPC exhibits the best sensing properties to VOCs due to the combined effect of low activation energy, adsorption/desorption of oxygen ions and the mesoporous hierarchical structure. (C) 2014 Elsevier B.V. All rights reserved.