Selectively enhanced gas-sensing performance to n-butanol based on uniform CdO-decorated porous ZnO nanobelts

Abstract

Due to its porous structure and synergetic sensing effect, the as-prepared CdO-decorated porous ZnO nanobelts exhibit a greatly enhanced sensing selectivity to n-butanol with a low detection limit of less than 5 ppb and excellent stability/repeatability. • CdO-decorated porous ZnO nanobelts were prepared through a cation-exchange reaction and subsequent calcination in air. • As-prepared porous nanobelts exhibited an enhanced selectivity to n-butanol with excellent stability/repeatability. • The excellent sensing performance is mainly ascribed to porous structure and synergetic sensing effect of CdO and ZnO. ZnO porous nanobelts decorated with different concentrations of CdO were precisely prepared via a two-step approach consisting of a cation-exchange reaction and subsequent calcination in air. After partially exchanged with Cd 2+ , the morphology of the ZnSe∙0.5N 2 H 4 precursor nanobelts was well preserved due to the spatial confinement effect. When thermally oxidized in air, the partially exchanged precursor nanobelts were changed into ZnO porous nanobelts decorated with CdO. Notably, CdO was uniformly distributed on the porous ZnO nanobelts. In contrast to bare porous ZnO nanobelts, the as-prepared CdO-decorated porous ZnO nanobelts exhibited a better sensing performance to volatile organic compounds. Moreover, an enhanced sensing selectivity to n-butanol was obtained. 9 at% CdO-decorated porous ZnO nanobelts displayed the best relative response of approximately 112 to 10 ppm of n-butanol. In addition, a low detection limit of less than 5 ppb was achieved with excellent stability and repeatability, suggesting that the fabricated gas sensors based on CdO-decorated porous ZnO nanobelts can be used for practical applications.