Graphene/Intermetallic PtPb Nanoplates Composites for Boosting Electrochemical Detection of H₂O₂ Released from Cells

Rational design and construction of electrocatalytic nanomaterials is vital for improving the sensitivity and selectivity of nonenzymatic electrochemical sensors. Here, we report a novel graphene supported intermetallic PtPb nanoplates (PtPb/G) nanocomposite as an enhanced electrochemical sensing platform for high-sensitivity detection of H₂O₂ in neutral solution and also released from the cells. The intermetallic PtPb nanoplates are first synthesized via a simple wet-chemistry process and subsequently assembled on graphene via a solution-phase self-assembly approach. The obtained nanocomposite exhibits excellent electrocatalytic activity for the electrochemical reduction of H₂O₂ in a half-cell test and can detect H₂O₂ with a wide linear detection range of 2 nM to 2.5 mM and a very low detection limit of 2 nM. Under the same conditions, the sensitivity of PtPb/G for the detection of H₂O₂ is more than 12.7 times higher than that of commercial Pt/C. The high-density of electrocatalytic active sites on the unique PtPb nanoplates and the synergistic effect between PtPb nanoplates and graphene appear to be the main factors in contributing to the outstanding electroanalytical performance. The PtPb/G can be also used for the practical detection of H₂O₂ released from Raw 264.7 cells.