Engineering FeCo alloy@N-doped carbon layers by directly pyrolyzing Prussian blue analogue: new peroxidase mimetic for chemiluminescence glucose biosensing

Abstract

Herein, we report the synthesis of FeCo alloy@N-doped carbon layers (FeCo@NC), a new peroxidase mimetic, by directly pyrolyzing the Fe^III–Co Prussian blue analogue (Fe^III–Co PBA). The FeCo@NC composite showed excellent peroxidase-like activity due to its highly active FeCo alloy, M–N species (Co–N and Fe–N) and N-doped carbon layers with hierarchical pore nanostructures, which were formed via simple heat treatment of Fe^III–Co PBA without additional C and N sources. In particular, the obtained FeCo@NC hybrid presented high CL activity with more than 85-fold enhancement in the CL emission of the H₂O₂–luminol system, and long-term stability compared with FeCo alloy nanoparticles. The CL response showed a linear range of 0.01–40 μM H₂O₂ with a limit of detection of 2.5 nM. When coupled with glucose oxidase, we developed a new CL sensing method for the detection of glucose in the linear range of 10 nM to 10 μM with a detection limit of 8.5 nM. This FeCo@NC-based glucose biosensor displayed rapidity, high precision and good reproducibility when utilized to analyze real biological samples. Expectedly, FeCo@NC, as a new peroxidase mimetic, exhibits great potential for monitoring glucose levels in clinical diagnosis.