Halogen-doped CQDs as a modulation of fractional function sensing in ZIF composites

Abstract

This study draws inspiration from the partition-function sensing mechanism of plant cells for purifying harmful gas molecules. The size of the pore size of ZIF-8 sieving gas molecules was modulated by halogen-doped carbon quantum dots (CQDs) during the formation of ZIF-8. Notably, the difference in electronegativity of different halogens makes the sieving pore size of ZIF-8 tunable in the nanometer range, which greatly enhances the selectivity of the composite. In addition, the halogen-doped carbon quantum dots modulate the structure, band gap, and impedance of the composites, enabling the detection of specific gases on the order of ppb. Using X-ray photoelectron spectroscopy, simulation data and density-functional theory, we find that halogen-doped CQDs can fine-tune the pore size of ZIF-8 by influencing the chemical bond lengths by affecting the positions of atoms on the imidazole ring. Plants in nature are similarly characterized in that different components act as sensors for characteristic gas components and synergistically promote the adsorption and purification processes of gas molecules. This study provides an innovative means of modifying the structure and properties of ZIF materials and introduces the concept of plant-like gas multi-sensing in the field of gas sensing research.