Synergistic Ru/Co sites in N-doped carbon framework for simultaneous electrochemical detection of hydroquinone and...

Hydroquinone (HQ) and catechol (CC) are two representative dihydroxybenzene isomers commonly detected in environmental water. Their highly similar molecular structures and redox behaviors often lead to severe signal overlap and mutual interference during simultaneous electrochemical detection. Owing to its high sensitivity, rapid response, operation simplicity, and cost effectiveness, electrochemical sensing is widely regarded as an effective strategy for HQ and CC detection. In this regard, the development of electrocatalytic materials with high activity and strong signal discrimination capability is essential for the selective and simultaneous analysis of these two toxic phenolic pollutants.

In this work, a bimetallic MOF-derived Ru/Co catalyst embedded in an N-doped carbon framework (Ru/Co-NC) is prepared and applied as an electrocatalytically active interface for the simultaneous detection of HQ and CC. Structural characterization verifies the successful incorporation of Ru and Co species into the N-doped carbon framework and reveals a porous architecture with abundant accessible active sites. Owing to the combined effects of bimetallic coupling and the conductive carbon support, the Ru/Co-NC-modified electrode shows improved interfacial charge transfer and enhanced electrochemical oxidation responses toward both analytes. Under the optimized conditions, the Ru/Co-NC-based sensor delivers wide linear ranges and low detection limits of 0.151 μM for HQ and 0.128 μM for CC, together with well-resolved oxidation signals. In addition, the sensing platform displays good selectivity, reproducibility, repeatability, and storage stability. Its practical applicability is further demonstrated by satisfactory recoveries obtained for tap water and river water sample analysis.

The superior sensing performance of Ru/Co-NC originates from the synergistic interaction of bimetallic active sites with the porous N-doped carbon framework, which promotes charge transfer and improves analyte discrimination. This work demonstrates the promise of bimetallic MOF-derived electrocatalysts for building high-performance electrochemical sensing interfaces for toxic phenolic pollutants.