Biomimetic graphene-supported ultrafine platinum nanowires for colorimetric and electrochemical detection of hydrogen peroxide.

The detection of hydrogen peroxide (H 2 O 2 ) is of great significance in environmental monitoring, enzymatic reactions, and disease diagnosis. Here we present the peptide-mediated biomimetic synthesis of ultrafine platinum nanowires (PtNWs) on graphene oxide (GO) nanosheets for the formation of functional hybrids, which show high potential for the fabrication of colorimetric and electrochemical sensors for the detection of H 2 O 2 with high performance. A multifunctional peptide with the sequence KIIIIKYWYAF was designed to create peptide nanofibers (PNFs) via a controllable self-assembly process, which serves as a bridge between GO nanosheets and PtNWs to form PtNWs-PNFs/GO hybrids. On this basis, a dual-mode sensor platform for both colorimetric and electrochemical sensing of H 2 O 2 was fabricated successfully. The obtained results indicate that the synthesized PtNWs-PNFs/GO hybrids could catalyze the decomposition of H 2 O 2 to generate ˙OH radicals with a significant current response, and the ˙OH radicals are capable of overoxidizing 3,3',5,5',-tetramethylbenzidine (TMB), producing a blue-colored species with a distinct color change for colorimetric sensing. In addition, due to its high catalytic activity, the fabricated PtNWs-PNFs/GO hybrid-based electrochemical sensor exhibits a wider linear detection range of 0.05 μM-15 mM and a low detection limit of 0.0206 μM, which can be applied to detect H 2 O 2 with high selectivity and sensitivity. Our study provides a green and environmentally friendly synthetic strategy for the preparation of biomimetic materials from PtNWs, and the fabricated colorimetric/electrochemical dual-mode H 2 O 2 sensor platform will have a great impact in bioanalysis, environmental monitoring, and biomedicine.