Construction of hierarchical Tourmaline@ZnO/MWCNT micro-nanostructured composite and its conductometric gas sensibility for N-butanol detection

Abstract

Modification of traditional metal oxides to prepare gas sensors with excellent response and high selectivity for monitoring air pollution, is a pivotal indicator for the development of gas sensing technologies. In this research, the core-shell Tourmaline@ZnO/MWCNT micro-nanostructured composite was successfully constructed and prepared by the uniform co-precipitation and hydrothermal methods, which effectively achieved the high sensitivity to n-butanol. The structure, morphology and surface electron valence state were characterized by employing important analytical techniques. With tourmaline as the inner-core and MWCNT-interspersed ZnO nanosheets as the outer-shell, the uniquely hierarchical micro-nanostructure covered a larger specific surface area, which provided more active sites during the reaction. Meanwhile, the performance assessments demonstrated that the proposed micro-nano structure exhibited exceptional gas-sensing properties, while Tourmaline@ZnO/ 0.9%MWCNT sensor reaching the highest response value to 185.8–100 ppm n-butanol far exceeding other detected gases, additionally with a faster response-recovery time. The presence of tourmaline and the interspersion of MWCNT played a synergistic effect on the enhancement of the properties for ZnO-based gas sensors, which brought about a beneficial impact on the carrier transport. This technical strategy should be of certain significance in the intelligent preparation and extensive application of high-performance sensing devices in the future.