Biomorphic ZnO Nanotubes for n-Pentanol Sensing

Abstract

It is of great practical significance to develop portable and conductometric sensors for detecting flammable and explosive high-energy n-pentanol vapor. In view of the very few reports on metal oxide-based n-pentanol sensors, herein, biomorphic ZnO nanotubes were synthesized through a zinc salt impregnation–calcination method using poplar branch as a biotemplate. The multistage porous ZnO-500 tube arrays obtained from calcination at 500 °C are cross-linked by small-size nanoparticles, which are beneficial to the rapid adsorption and diffusion of n-pentanol vapor with a long alkyl chain. A ZnO-500-based sensor presents high and fast response (S = 221.0; Tres = 4 s) to 100 ppm n-pentanol vapor at 252 °C, as well as a low detection limit (100 ppb) and a wide linear relationship. Under the synergistic effect of inherent characteristics of the biomorphic structure and biotemplate imprinting, the above comprehensive gas-sensing indicators are significantly superior to those of the reported metal oxide-based sensors. Thus, the porous ZnO-500 nanomaterials prepared by a simple, low-cost, and controllable biotemplate method have the potential to be fabricated as candidates for the rapid and accurate detection of trace amounts of n-pentanol.