Two-Dimensional Conjugated Metal-Organic Frameworks with Large Pore Apertures and High Surface Areas for NO2 Selective Chemiresistive Sensing

The emergence of two-dimensional conjugated metal-organic frameworks (2D c-MOFs) with pronounced electrical properties (e.g., high conductivity) has provided a novel platform for efficient energy storage, sensing, and electrocatalysis. Nevertheless, the limited availability of suitable ligands restricts the number of available types of 2D c-MOFs, especially those with large pore apertures and high surface areas are rare. Herein, we develop two new 2D c-MOFs (HIOTP-M, M=Ni, Cu) employing a large p-& pi; conjugated ligand of hexaamino-triphenyleno[2,3-b:6,7-b & PRIME;:10,11-b & PRIME;& PRIME;]tris[1,4]benzodioxin (HAOTP). Among the reported 2D c-MOFs, HIOTP-Ni exhibits the largest pore size of 3.3 nm and one of the highest surface areas (up to 1300 m(2) g(-1)). As an exemplary application, HIOTP-Ni has been used as a chemiresistive sensing material and displays high selective response (405 %) and a rapid response (1.69 min) towards 10 ppm NO2 gas. This work demonstrates significant correlation linking the pore aperture of 2D c-MOFs to their sensing performance.

Automated summary

The development of two-dimensional conjugated metal-organic frameworks (2D c-MOFs) with remarkable electrical properties has created a new platform for efficient energy storage, sensing, and electrocatalysis. However, the availability of suitable ligands is limited, especially for 2D c-MOFs with large pore apertures and high surface areas. In this study, two new 2D c-MOFs (HIOTP-M, M=Ni, Cu) are successfully synthesized using a large conjugated ligand HAOTP. Among the reported 2D c-MOFs, HIOTP-Ni exhibits the largest pore size of 3.3 nm and one of the highest surface areas (up to 1300 m(2) g(-1)). As a demonstration, HIOTP-Ni shows promising chemiresistive sensing properties towards 10 ppm NO2 gas with high selectivity (405%) and a rapid response (1.69 min). This work highlights the significant correlation between the pore aperture of 2D c-MOFs and their sensing performance.