Metal–Organic Framework-Derived Porous Hollow Co<sub>3</sub>O<sub>4</sub>/ZnO Nanofibers for H<sub>2</sub>S Sensing
Xiaoyan Song, Zhaoyang Pan, Zhipeng Wang, Wanchun Huang, Jinfeng Xing
Abstract
Metal–organic framework (MOF) materials with various shapes and sizes are recognized as outstanding templates for preparing porous metal oxides used as gas-sensitive materials. Here, a facile synthetic strategy is developed to assemble ZIF-67 and ZIF-8 into Co 3 O 4 /ZnO hollow porous nanofibers with an MOF-on-MOF heterojunction for gas-sensing applications. The fabricated sensor using this innovative MOF-on-MOF nanomaterial demonstrates high gas sensor response, low limit of detection, remarkable selectivity, and excellent stability to H 2 S gas. Notably, the Co 3 O 4 /ZnO nanofibers show a maximum response of 50 and 1080 at 200 ppb and 5 ppm of H 2 S under optimal conditions, respectively. Furthermore, the gas-sensing mechanism is proposed in detail, and theoretical calculations based on first-principles further reveal the performance of Co 3 O 4 /ZnO nanofibers in enhancing the sensing of H 2 S. This study offers an approach for fabricating dual MOF-based nanostructures with abundant pores and high surface area for high-performance gas-sensing applications.