A Designed ZnO@ZIF-8 Core–Shell Nanorod Film as a Gas Sensor with Excellent Selectivity for H2 over CO

4 years ago

A Designed ZnO@ZIF-8 Core–Shell Nanorod Film as a Gas Sensor with Excellent Selectivity for H2 over CO

Shunshun Xiong, Zhenghao Mao, Xiaonan Wu, Sheng Hu, Xinggui Long

The development of H2 gas sensors is important for H2 production as a fuel. In this work, a ZnO@ZIF-8 core–shell nanorod film is designed and synthesized as a gas sensor through a facile solution deposition process. This film shows an excellent selective response for H2 over CO. By fine-tuning the reaction conditions, a ZnO@ZIF-8 core–shell structure with a thin, fine-grain, porous ZIF-8 shell is obtained. Owing to the facile H2 penetration through the ZIF-8 thin shell (≈110 nm) and the increased oxygen vacancies for the complex film, the ZnO@ZIF-8 nanorod film shows a higher H2 sensitivity than a raw ZnO nanorod film. More importantly, the ZnO@ZIF-8 nanorod film shows no response for CO at 200 °C. Because of the fine-grain confinement of the porous ZIF-8 shell (<140 nm), the molecular sieving effect is strengthened, which allows the effective separation of H2 over CO. This work provides a promising strategy for the design of high-performance H2 sensors. Fabricating gas sensors: A ZnO@ZIF-8 core–shell nanorod film is fabricated through a solution deposition process. Fine-tuning the reaction conditions allows a ZnO@ZIF-8 core–shell structure with a thin, fine-grain, porous ZIF-8 shell to be obtained. The penetration of H2 through the ZIF-8 layer is easy because of the thin shell thickness, whereas passing of CO is hindered owing to the fine-grain confinement of the porous ZIF-8 shell (see figure). Selectivity for H2 over CO is realized using this ZnO@MOF complex.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201700320