Dual-metal sites synergy in Fe/V-N-C catalyst: Boosting ECL signals for ultrasensitive detection of aflatoxin B1 in corn and peanut.

Abstract

Single-atom catalysts maximize atomic utilization efficiency but suffer from limited activity and stability. Bimetallic alternatives overcome these limitations via synergistic interactions between adjacent metal sites. Herein, we synthesized a bimetallic single-atom catalyst with Fe and V uniformly distributed in N-doped porous carbon (Fe/V-N-C) via one-step pyrolysis. Synergistic electron transfer between the binary metals optimized active-site electron density, cooperatively activating H2O2 to boost reactive oxygen species generation and enhance ECL efficiency. The Fe/V-N-C catalyst showed 6.50-fold ECL enhancement, surpassing monometallic Fe-N-C (3.43 times) and V-N-C (2.05 folds). The alternating-current voltammetry (ACV)-ECL coupling and supplementary techniques confirmed that enhanced H2O2 affinity drives the improved catalytic performance, coupled by clarifying the ECL mechanism. The "signal on-off-on" ECL aptasensor was designed for ultra-sensitive aflatoxin B1 detection, achieving a dynamic linear range of 0.05-100 ng mL-1 and a low detection limit of 0.0025 ng mL-1. This work advances single-atom catalyst design for stable ECL sensing platforms.