Oxygen vacancy dual regulation strategy realizes wide humidity range monitoring of UIO-66(Ce)-derived CeO2 for intelligent food manufacturing

Abstract

High-performance humidity sensors have significant potential applications in areas such as smart homes and digital healthcare, but the limited humidity sensing performance of materials hinders their practical application. One major challenge in enhancing the sensing performance of humidity-sensitive materials is the effective regulation of oxygen vacancy content within their crystal structures. In this study, we propose a dual regulation strategy of “ligand induced-pyrolysis synergy” to control the oxygen vacancy content effectively. Specifically, Metal–Organic Framework (MOF) materials containing oxygen vacancies were synthesized using a monocarboxylic acid conditioning method. We further increased the oxygen vacancy content in the MOF derivatives by adjusting the heat treatment temperature. The prepared U6C-20-400 sensor demonstrated excellent performance across a wide humidity range of 3–97% relative humidity (RH), with a rapid response/recovery time of just 0.5 s and 1.2 s. Furthermore, it effectively monitored food as it transitioned from raw to cooked and even burnt during cooking. This study offers valuable insights for developing high quality humidity sensors tailored for next-generation smart home applications.