Rationally designed titanium-based metal–organic frameworks for visible-light activated chemiresistive sensing

Abstract

Simultaneously realizing high sensitivity and high selectivity at room temperature is still a big challenge for designing chemiresistive gas sensing materials. In this work, the first visible-light active MOF sensing material was rationally designed and prepared to meet this challenge. Different from the reported MOFs, FIR-120 combines a high stability, permanent porosity and visible light active titanium-phenol functional motif in one structure through an interpenetrating structure strategy. These features endow FIR-120 with unique photo-physic/chemistry properties that enable the highest sensitivity, lowest experimental limit-of-detection (LOD) and excellent selectivity to NO₂ among all reported MOFs and MOF composite materials at room temperature. Moreover, the structure–sensing relationship is studied through experiments and theoretical calculations. This work provides guidance for the design and synthesis of high-performance visible-light active MOFs and leads to a new type of gas sensing material.