Two-Dimensional Bimetallic Phthalocyanine Covalent-Organic-Framework-Based Chemiresistive Gas Sensor for ppb-Level NO 2 Detection

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2023-05, Vol.13 (10)
• Main Authors: Chen, Xiyu, Zeng, Min, Yang, Jianhua, Hu, Nantao, Duan, Xiaoyong, Cai, Wei, Su, Yanjie, Yang, Zhi
• Format: Article
• Language: English
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano13101660

Two-dimensional (2D) phthalocyanine-based covalent organic frameworks (COFs) provide an ideal platform for efficient and rapid gas sensing-this can be attributed to their regular structure, moderate conductivity, and a large number of scalable metal active centers. However, there remains a need to explore structural modification strategies for optimizing the sluggish desorption process caused by the extensive porosity and strong adsorption effect of metal sites. Herein, we reported a 2D bimetallic phthalocyanine-based COF (COF-CuNiPc) as chemiresistive gas sensors that exhibited a high gas-sensing performance to nitrogen dioxide (NO ). Bimetallic COF-CuNiPc with an asymmetric synergistic effect achieves a fast adsorption/desorption process to NO . It is demonstrated that the COF-CuNiPc can detect 50 ppb NO with a recovery time of 7 s assisted by ultraviolet illumination. Compared with single-metal phthalocyanine-based COFs (COF-CuPc and COF-NiPc), the bimetallic structure of COF-CuNiPc can provide a proper band gap to interact with NO gas molecules. The CuNiPc heterometallic active site expands the overlap of -orbitals, and the optimized electronic arrangement accelerates the adsorption/desorption processes. The concept of a synergistic effect enabled by bimetallic phthalocyanines in this work can provide an innovative direction to design high-performance chemiresistive gas sensors.