PdCu@rGO-based Electrochemical Sensor for Rapid Detection of Catechol

Catechol, a prevalent phenolic pollutant in food products, poses a significant threat to food safety, necessitating the development of rapid and sensitive detection methods. To overcome the limitations of conventional analytical techniques, such as expensive equipment and operational complexity, electrochemical sensors have gained considerable attention owing to their rapid response and facile miniaturization. However, the rational design of sensing materials that exhibit both high sensitivity and selectivity remains a significant challenge. Herein, a series of PdCu bimetallic nanoparticles supported on reduced graphene oxide (PdCu@rGO) composites with varying Pd/Cu molar ratios was synthesized via a one-step liquid-phase reduction method. Owing to the synergistic electronic effects between Pd and Cu and the high electrical conductivity of the rGO support, the resulting nanocomposites exhibited excellent electrocatalytic activity toward catechol oxidation. At the optimal Pd/Cu molar ratio of 1:2, the fabricated Pd1Cu2@rGO/SPE sensor demonstrated a broad linear range of 0.5–500 μM, a low limit of detection of 200 nM (S/N = 3), good repeatability (RSD = 4.9%), and robust anti-interference capability. Furthermore, the proposed sensor was successfully applied to the detection of catechol in spiked green tea and fruit juice samples without complex pretreatment, achieving satisfactory recoveries of 91.0–101.4% and 98.6–104.8%, respectively. This work provides a reliable platform for the rapid, on-site screening of catechol in food matrices and offers valuable experimental insights into the rational design of bimetallic alloy–graphene heterostructures.