Synthesis of transition metal sulfide functionalized hierarchically porous carbons and their application as colorimetric-electrochemical dual-mode nanozyme sensing platform for dopamine

Transition metal sulfide functionalized hierarchically porous carbons as colorimetric-electrochemical dual-mode nanozyme sensing platform for the visual qualitative colorimetric and quantitative electrochemical detection of dopamine (DA) are synthesized by hydrothermal method using Chinese fevervine herb rich in sulfur as the carbon source and sulfur source, and different transition metal chlorides as the metal sources. The introduction of FeCl3 is more favorable to the generation of micropores, while the introduction of other transition metal chlorides is beneficial to the generation of mesopores and macropores. FeS2 functionalized hierarchically porous carbon (FSPC) with large specific surface area shows better conductivity, more excellent electrocatalytic ability, and higher peroxidase-like and oxidase-like activities. The inhibitory colorimetric assay for DA designed by the oxidase-like properties of FSPC without the intervention of H2O2, making the reaction system more stable. FSPC displays excellent electrochemical responses for DA with about 50-fold peak current compared with bare electrode, and possesses a low detection limit of 0.015 μM (S/N = 3) in a wide linear range of 0.05–1000 μM. This work will provide a new idea for the nanozyme sensing of DA with colorimetric-electrochemical dual-mode and a new possibility for application in clinical medicine.