FeNi@NCNT derived from MOF-on-MOF pyrolysis for simultaneous electrochemical detection of dihydroxybenzene isomers

Abstract

The development of efficient technologies capable of rapid and selective sensing of toxic hydroquinone (HQ) and catechol (CC) in water systems represents an urgent priority for environmental monitoring. Herein, we established a novel electrochemical sensor for HQ and CC sensing using a structure of FeNi alloyed nanoparticles interconnected by N-doped carbon nanotubes (FeNi@NCNT). This composite was prepared through the pyrolysis of a MOF-on-MOF structure (i.e., FeNi MOF@ZIF-8), in which the formation of CNT was caused by the selfcatalysis of metallic Zn. Synergy between bimetallic nanoparticles and N-dope CNT contributes to enhanced electrical conductivity, greater electrocatalytic activity, and improved sensing capability for HQ and CC, gaining two well-defined and distinguishable peaks. Featuring high selectivity and a wide linear range, the fabricated FeNi@NCNT electrocatalyst also achieves a remarkably low detection limit of 3 nM and 69 nM for HQ and CC, respectively. As a comparison, a recently reported CoP/N,P-C-based electrochemical sensor exhibited LODs of 10 nM and 150 nM for HQ and CC, respectively, demonstrating high improvements in sensitivity with our system. The practical applicability of this method was validated by good recovery in real water sample, highlighting their highly accurate, precise, and robust potential for environmental analysis. This work thus presents a simple method to fabricate FeNi@NCNT with hierarchical structure with exceptional electrocatalytic activity for selective dihydroxybenzene electrochemical sensors.