Confining Fe nanoparticles within N-doped carbon nanotubes for boosting electrochemical sensing of 4-aminophenol

Abstract

4-Aminophenol (4-AP) is a main synthetic raw material of great significance, and it has been found that excessive 4-AP in human body might lead to a variety of health problems. Developing a reliable electrochemical sensor of 4-AP is necessary for protecting public health and environmental quality. Carbon nanotubes confined metallic nano-catalysts feature plenty of active sites, large surface area and high-speed electron transfer, which endowed them with high catalytic performance, good electroconductibility and considerable potential in electronic sensor applications. In the present work, Fe nanoparticles confined in carbon nanotubes doped with nitrogen (Fe-N-CNTs) were synthesized by pyrolysis of a composite of Fe-MIL-101 and ZIF-8. The synthesized Fe-N-CNTs functioned as a modifier for boosting electrocatalytic performance, allowing for the highly sensitive determination of 4-AP, which is mainly due to the superior electrical conductance and abundant active sites of Fe-N-CNTs. Moreover, the established Fe-N-CNTs electrochemical sensor owned a limit of detection (LOD) of 75 nM and linear ranges of 0.2 to 50 μM for detecting 4-AP. This sensor owned high recovery rates ranged from 102.2 % to 105.9 % for 4-AP detection in actual samples, highlighting its practicable applicability. This work not only paves a way to design metal nano-catalyst confined in carbon nanotubes but also presents a novel technique for sensitive electrochemical sensors.