A Designed ZnO@ZIF-8 Core-Shell Nanorod Film as a Gas Sensor with Excellent Selectivity for H 2 over CO

The development of H gas sensors is important for H 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 H 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 H 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 H 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 (