Direct Electrodeposition of Bimetallic Nanostructures on Co-Based MOFs for Electrochemical Sensing of Hydrogen Peroxide

Hydrogen peroxide (H₂O₂) is the most significant reactive oxygen species in biological systems. Here, we reported an electrochemical sensor for the detection of H₂O₂ on the basis of bimetallic gold-platinum nanoparticles (Au₃Pt₇ NPs) supported by Co-based metal organic frameworks (Co-MOFs). First, Au₃Pt₇ NPs, with optimal electrocatalytic activity and accessible active surface, can be deposited on the surface of the Co-MOF-modified glassy carbon electrodes (Au₃Pt₇/Co-MOFs/GCE) by one-step electrodeposition method. Then, the electrochemical results demonstrated that the two-dimensional (2D) Co-MOF nanosheets as the supporting material displayed better electrocatalytic properties than the 3D Co-MOF crystals for reduction of H₂O₂. The fabricated Au₃Pt₇/2D Co-MOF exhibited high electrocatalytic activity, and the catalytic current was linear with H₂O₂ concentration from 0.1 μM to 5 mM, and 5-60 mM with a low detection limit of 0.02 μM (S/N = 3). The remarkable electroanalytical performance of Au₃Pt₇/2D Co-MOF can be attributed to the synergistic effect of the high dispersion of the Au₃Pt₇ NPs with the marvelous electrochemical properties and the 2D Co-MOF with high-specific surface areas. Furthermore, this sensor has been utilized to detect H₂O₂ concentrations released from the human Hela cells. This work provides a new method for improving the performance of electrochemical sensors by choosing the proper support materials from diverse crystal morphology materials.