COF-derived multicore-shell FeCo nanoalloys@N-doped carbon for sensitive electrochemical detection of caffeic acid

Caffeic acid is a key indicator of wine quality, but its sensitive and accurate detection remains challenging due to the lack of high-performance sensing materials. Metal/N-doped porous carbon (M/NPC) electrocatalysts with abundant catalytic sites are promising to address this issue. Herein, a FeCo nanoalloy encapsulated in NPC (FeCo@NPC) was designed and synthesized via a "covalent organic framework (COF) adsorption-pyrolysis" strategy. The COF template enabled homogeneous dispersion and stabilization of FeCo. The resulting FeCo@NPC exhibited hierarchical porosity, abundant metal-N_x sites, and strong bimetallic synergetic effects, leading to exceptional electrocatalytic activity towards caffeic acid oxidation. The constructed sensor achieved high sensitivity (5.195 and 0.895 μA μM^-1) and selectivity. It was successfully applied for caffeic acid detection in commercial tablets and wines, and further tracked changes in caffeic acid concentration in red wine over post-opening time. This work provides a general design strategy for designing high-performance electrocatalysts for food quality control.