3D Cuprous Iodide Cluster-Covalent Organic Framework for Ultrasensitive and Highly Selective Trace HF Detection at...

Hydrofluoric acid (HF) poses a serious and irreversible threat to human health necessitating the development of highly sensitive and selective detection materials. Herein, a three-dimensional cuprous iodide cluster-based covalent organic framework (CuI-MCOF), with diamond topology has been successfully prepared, which shows an ultrafast and highly sensitive response to HF gas. At room temperature, CuI-MCOF displays an exceptional response of 7188% toward 100 ppm HF, with remarkably rapid response/recovery times of 3 s/2 s at 4 ppm. Notably, the sensor achieves an ultralow detection limit of 21 ppb, outperforming previously reported HF sensors. Moreover, it demonstrates outstanding selectivity and anti-interference performance, maintaining stable responses to 4 ppm HF even in the presence of 16 interfering gases (100 ppm each). Experiments combined with density-functional theory calculations reveal that the imine-linker N atoms serve as reversible HF adsorption-desorption sites, while the electron-rich CuI clusters enhance dipole interactions and facilitate charge transfer. Leveraging these properties, an on-chip miniaturized perceptron system integrated with evaluation algorithms is developed for anti-interference HF discrimination, spatiotemporal distribution estimation, and leakage source prediction. This work provides a new strategy for designing high-performance HF sensors and expands the application of cluster-based COFs in gas sensing.