Fe-pCOFs/MoS2-MWCNTs nanocomposite with enzyme-like activity for efficient electrochemical detection of hydrogen peroxide from living cells

Hydrogen peroxide (H 2 O 2 ) is an important reactive oxygen species, and its abnormal concentration can cause cell distortion and apoptosis, leading to occurrence of various diseases. Therefore, real-time and sensitive monitoring of H 2 O 2 is essential for early disease diagnosis and pathological research. Herein, a novel nanocomposite of Fe-porphyrin covalent organic frameworks decorated with molybdenum disulfide and multi-walled carbon nanotubes (Fe-pCOFs/MoS 2 -MWCNTs), which had glorious enzyme-like activity, was reported for efficient electrochemical detection of H 2 O 2 . The prepared Fe-pCOFs nanosheets with a large specific surface area and fully dispersed Fe 2+ active sites, could enhance mass transfer and atomic utilization, thereby contributing to excellent catalytic efficiency toward H 2 O 2 . The flower-like MoS 2 nanoflakes not only could catalyze the reduction reaction of H 2 O 2 , but also could serve as co-catalyst and form a catalytic cycle with Fe 2+ of Fe-pCOFs, contributing the continuous emergence of catalytic active sites. The highly conductive MWCNTs was employed to promote electron transfer rate. Ultimately, the obtained Fe-pCOFs/MoS 2 -MWCNTs exhibited excellent electrocatalytic activity and conductivity, significantly amplifying the H 2 O 2 response signal. Under the optimal conditions, the sensor had a wide detection range from 20 to 2650 μΜ for H 2 O 2 with a detection limit as low as 2.2 μΜ. Moreover, the sensor successfully recorded trace amounts of H 2 O 2 released from RAW264.7 cells, showing promising application for real-time and sensitive monitoring of H 2 O 2 in clinic or pathological research.