Covalent-organic framework/carbon nanotubes for electrochemical detection of o-nitrophenol

Abstract

Covalent organic frameworks (COFs) have aroused much attention as candidate materials for constructing electrochemical sensors. However, their inherent low conductivities have limited their sensing applications. Here, a novel COF/carbon nanotubes (CNTs) composite is prepared via a straightforward ultrasonic method, incorporating amino-functionalized CNTs (NH2-CNTs) into COF composed of 1, 3, 5-benzenetricarboxaldehyde and 1,4-diaminobenzene. The resulting COF/NH2-CNTs composite exhibits high specific surface area, improved conductivity, fast electron transfer capability due to the high porosity of COF, the introduction of NH2CNTs, and the conjugate interaction between CNTs and COF. The proposed COF/NH2-CNTs-based sensor offers an amplified current toward the electrochemical sensing of o-nitrophenol (o-NP). Notably, the sensor exhibits a wide linear detection range (0.1-100 and 100-1000 mu M), a high sensitivity (8.66 and 1.44 mu A/(mu M cm2)), and a very low detection limit (0.03 mu M). Moreover, it is successfully applicable in the quantitative analysis of o-NP in lake water samples with satisfactory recoveries (97.0-105.3 %). This work not only demonstrates the viability of COF-based sensors for the trace-level detection of nitrobenzene contaminants but also enriches the variety of COF-based sensing materials.